An Illustrated Guide to Common Stream Diatom Species from Temperate Australia

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An Illustrated Guide to Common Stream
Diatom Species from Temperate
Australia
Jason A. Sonneman1, Adam Sincock2, Jennie Fluin1,
Michael Reid1, Peter Newall3, John Tibby1and Peter Gell2
1. Monash University, Clayton, 3800, Victoria, Australia
2. Adelaide University, Adelaide, 5005, South Australia, Australia
3. Environmental Protection Agency, Melbourne, 3000, Victoria, Australia.
Cooperative Research Centre for Freshwater Ecology
Identification Guide No 33
Presented at the 2nd Australian Algal Workshop
Adelaide University
17-19th April, 2000.
A project supported by the Land & Water Resources Research & Development Corporation.

ii
ãCopyright. Cooperative Research Centre for Freshwater Ecology,
Albury.
Illustrations may not be used in any publications without the proper written
permission of the copyright owner.
Identification Guide Series edited by John H. Hawking.
First published 1999 by the Cooperative Research Centre for Freshwater
Ecology, Ellis Street, Thurgoona, NSW 2640.
National Library of Australia Cataloguing-in-Publication
Sonneman, Jason A.
An illustrated guide to common stream diatom species from
temperate Australia.
Bibliography.
ISBN 1 876144 35 1.
ISSN 1321-280X.
1. Diatoms –Australia. 2. Diatoms –Australia -Identification.
I. Murray-Darling Freshwater Research Centre. II. Title. (Series :
Identification guide (Cooperative Research Centre for Freshwater
Ecology (Australia)). ; no. 33).
579.850994
Front Cover:
Colour photographs: Top left: Cyclotella stelligera
Bottom left: Surirella robusta var. splendida
Top right: Striatella/Polysiphonia? sp.
Bottom right: Licmophora sp.
Photographs by Peter Tyler
Background photographs:Top left:
Bottom left:
Top right:
Bottom right:
Photographs by Jeremy Pickett-Heaps

5
COMMON DIATOM SPECIES FROM TEMPERATE STREAMS
Genus Achnanthidium and related genera
Key to the common species
1a. Valves < 5 mm wide ............................................................................................................................ 2
1b. Valves > 5 mm wide ............................................................................................................................ 6
2a. Length to width ratio > 4, striae density usually >20/10 mm ................................................................ 3
2b. Length to width ratio < 4 .................................................................................................................... 4
3a. Striae density > 25/10 mm, ends slightly drawn, rostrate or subcapitate .Achnanthidium minutissimum
3b. Striae density < 25/10 mm, ends broadly rounded, valves strongly linear ............ Rossithidium pusillum
4a. Central area of raphid valve a transverse fascia, median striae shortened or missing on one or both sides
of the axial area of the araphid valve. Striae density 20-30/10 mm ....................................................... 5
4b. Valves otherwise formed ....................................................... Other species not included in this guide
5a. Ends rostrate to capitate, striae density < 30/10 mm ................................................. Achnanthes exigua
5b. Ends wedge shaped to subrostrate, striae density > 30/10 mm............................. Achnanthes subexigua
6a. Striae coarse (usually < 15/10 mm), obviously not punctate .................................................................. 7
6b. Striae finer: if coarse (< 15/10 mm), then appearing punctate ............................................................... 9
7a. Araphid valve having a horseshoe-shaped clear area on one side of the central area ............................. 8
7b. Araphid valve lacking a horseshoe-shaped clear area ................................... Planothidium delicatulum
8a. Central horseshoe-shaped area with a distinct marginal line ................. Planothidium frequentissimum
8b. Central horseshoe-shaped area without such a line ...................................... Planothidium lanceolatum
9a. Striae clearly punctate ....................................................................................................................... 10
9b. Striae not punctate or only indistinctly so ........................................................................................... 11
10a. Valves elliptical to linear elliptical, only araphid valve striae clearly punctate, 10-14/10 mm ...................
............................................................................................... Achnanthes oblongella (araphid valve)
10b. Valves lanceolate to rhombic-lanceolate, striae of both valves clearly punctate ............ Karayevia clevei
11a Central area of raphid valve a transverse fascia reaching margin of valve ........................................... 12
11b Central area of raphid valve tranversely widened but rarely reaching the valve margin, valve elliptical
to linear elliptical with very broadly rounded ends .................... Achnanthes oblongella (raphid valve)
12a Valve ends wedge-shaped to broad-rounded. Tranverse fascia on raphid valve usually distinctly larger
on
one side. Larger forms, usually > 15 mm long, striae density < 24/10 mm .......... Achnanthes hungarica
12b Valves ends subrostrate to capitate. Smaller forms usually < 15 mm long, striae density 20-30/10 mm .....
...........................................................................................................................................................13
13a. Striae density > 30/10 mm on both valves, ends subrostrate to rostrate Achnanthes cf. subexigua (part)
13b Striae density < 25/10 mm on araphid valve, up to 30/10 mm on raphid valve, ends rostrate to capitate ....
..................................................................................................................... Achnanthes exigua (part)

6
Achnanthes exigua
Grunow in Cleve & Grunow 1880 (Figs 2a-d)
Synonyms: Refer to individual variety descriptions.
Description: Valve linear, linear-elliptical to elliptical, sometimes appearing rectangular, with broadly
rounded, rostrate to subcapitate ends. Raphid valve: axial area narrow, widening towards the centre. Raphe
filiform. Central area transverse, forming a fascia that reaches the valve margins. Striae radial throughout,
becoming denser and tending to parallel at the ends. Araphid valve: axial area (pseudoraphe) narrow,
widening towards the centre. Central area absent, or one-sided, expanding to the valve margin due to the
absence of medial striae. Striae almost parallel in the centre, tending radial towards the ends. Length 12.5-14
(5-20) µm, width 4-5 (4-10) µm, striae density 20-25 (24-30)/10 µm.
Key references: Foged 1978, p. 25.
Holland & Clark 1989, p. 9, pl. 1, fig. 13.
John 1983, p. 70, pl. 30, figs 5, 6.
Krammer & Lange-Bertalot 1991, p. 38, figs 6: 4, 23: 1-27.
Patrick & Reimer 1966, p. 257, pl. 16, figs 21, 22.
Thomas 1983, p. 18, pl. 3, figs 17, 18.
Common varieties:
var. exigua
Syn: Stauroneis exilis Kützing 1833
Nominate variety, refer to description above.
var. constricta (Grunow) Hustedt 1922
Syn: Cocconeis exigua var. constricta Torka 1909
Valve constricted in the central region.
var. heterovalva Krasske 1930
Striae on raphid valve more dense, valve margins ± constricted.
Similar species: Achnanthes cf. subexigua(p. 9)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and moderately abundant,
particularly in upland areas. Preference for
circumneutral, clean water environments. Found in
epipelic and epilithic assemblages.
Fig. 2. Achnanthes exigua: (a-b) raphid valves: (a) Goulburn River, VIC, x1500; (b) Warren River, WA,
x1500; (c-d) araphid valves: (c) Franklin River, WA, x1500; (d) Ovens River, VIC, x1500.

7
Achnanthes hungarica
(Grunow) Grunow in Cleve & Grunow 1880 (Fig. 3)
Synonyms: Achnanthidium hungaricum Grunow 1863 (sensu Gell et al., 1999)
Achnanthes andicola (Cleve) Hustedt 1911
Achnanthes pseudohungarica Cholnoky-Pfannkuche 1966
Description: Valve linear-elliptical to lanceolate-elliptical with broadly-rounded to acutely-rounded ends.
Raphid valve: axial area narrow to broad, linear, sometimes slightly widened proximally. Raphe filiform,
distal raphe ends bent to opposite sides. Central area a transverse fascia, almost reaching margins, often
appearing wider on one side. Transapical striae weakly radial throughout the valve. Araphid valve: axial area
narrow, linear. Central area absent or extremely small, formed by a few slightly shortened medial striae.
Transapical striae weakly radiaal throughout the valve. Length 10-32 (6-45) µm, width 4-6 (4-8) µm, striae
density 18-22 (16-23)/10 µm.
Key references: Foged 1978, p. 26, pl. 14, figs 18, 19.
John 1983, p. 71, pl. 30, figs 11-14.
Germain 1981, p. 112, pl. 41, figs 38-45.
Holland & Clark 1989, p. 9, pl. 1, fig. 5.
Krammer & Lange-Bertalot 1991, p. 33, fig. 19: 1-15.
Patrick & Reimer 1966, p. 26, pl. 14, figs 18, 19.
Vyverman et al. 1995, p. 15, pl. 5. fig. 9.
Common varieties: None
Similar species: Achnanthidium minutissimum (p. 10)
Rossithidium pusillum (p. 16)
Sellaphora seminulum (p. 138)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 3. Achnanthes hungarica, Mullum
Mullum Creek, VIC, x1450.
Notes: Widespread but usually not abundant. Recorded
in epipelic and epilithic assemblages. Also epiphytic,
often in association with Lemna and Azolla roots.

8
Achnanthes oblongella
Ostrup 1902 (Figs 4a-h)
Synonyms: Achnanthes saxonica Krasske ex Hustedt 1933
Description: Valve elliptical to linear-elliptical with broadly rounded ends. Raphid and araphid valves
clearly distinct. Raphid valve: axial area narrow, linear, raphe filiform. Central area broad transversely
(fasciate), almost reaching margins. Striae extremely dense, weakly radial in the centre becoming strongly
radial at the valve ends. Araphid valve: axial area narrow to broad, linear to slightly lanceolate. Central area
absent. Striae conspicuously coarse (sometimes visibly punctate), widely spaced, parallel to weakly radial
(occasionally irregular) in the centre, becoming radial at the valve ends. Length 13-18 (7-20) µm, width 5.5-
8 (4-8) µm, striae density (raphid valve) 24-25 (23-27)/10 µm, striae density (araphid valve) 10-12(10-14)/10
µm.
Key references: Foged 1978, p. 29, pl. 14, figs 13-17.
Hodgson et al. 1997, p. 31, pl. 4, fig. 1.
Holland & Clark 1989, p. 9, pl. 1, fig. 12.
John 1983, p. 74, pl. 32, figs 5-8.
Krammer & Lange-Bertalot, p. 29, fig. 16: 1-14.
Vyverman et al. 1995, p. 18, pl 22, fig. 7.
Common varieties: None
Similar species: Achnanthes conspicua Mayer 1919 (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread, particularly in upland streams, and
can dominate a community. Most commonly recorded
in epilithic assemblages.
Fig. 4. Achnanthes oblongella: (a-c) raphid valves: (a) Blackwood River, WA, x1800; (b) Sheepwash Creek,
WA, x1800; (c) Dawesley Creek, SA, x1800; (d-h) araphid valves: (d) Sheepwash Creek, WA, x1800; (e)
Bremer River, SA, x1800; (f) Tookayerta Creek, SA, x1800; (g) Blackwood River, WA, x1800; (h)
Dawesley Creek, SA, x1800;

9
Achnanthes cf. subexigua
Hustedt 1934 (Figs 5a-f)
Synonyms: None
Description: Valve linear, with wedge-shaped, bluntly rounded ends. Raphid valve: axial area narrow and
linear. Raphe filiform, distal ends deflected to opposite sides. Central area widened transversely (appearing
almost fasciate), reaching the valve margins. Transapical striae highly dense and radial throughout the valve.
Araphid valve: axial area (pseudoraphe) conspicuously lanceolate. Central area transverse, rhomboid shaped,
almost reaching the valve margins. Transapical striae strongly radial throughout the valve. Length 12-16 (10-
16) µm, width 3-4 (3-4.5) µm, striae density 30-34 (32)/10 µm.
Key references: Krammer & Lange-Bertalot 1991, p. 40, fig. 23: 28-32.
Vyvermanet al. 1995, p. 20, pl. 8, fig. 1, pl. 22, figs 8-14, pl. 23, fig. 7.
Common varieties: None
Similar species: Achnanthes abundans Manguin 1954 (not described in this guide)
Achnanthes hungarica (p. 7)
Achnanthidium minutissimum (p. 10)
Eolimina minima (p. 136)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread in alpine areas, often found with
Rossithidium pusillum. Mostly recorded in epilithic
assemblages. Largely found in waters with low
nutrient and ionic concentrations. Many Achnanthes cf.
subexigua valves that we encounter are very similar to
Achnanthes abundans, and there is clearly need for
further taxonomic revision of these taxa.
Fig. 5. Achnanthes cf. subexigua, (a-f) Kiewa River, VIC, x2200.

10
Achnanthidium minutissimum
(Kützing) Czarnecki 1994 (Figs 6a-h)
Synonyms: Achnanthidium microcephalum Kützing 1844
Achnanthidium lineare W. Smith 1855
Achnanthes minutissima var. cryptocephala Grunow in Van Heurck 1880
Achnanthes minutissima var. inconspicua Ostrup 1910
Achnanthes minutissima var. scotica (Carter) Lange-Bertalot in Krammer &
Lange-Bertalot 1989
(Achnanthidium minutissima Kutzing sensu Gell et al. 1999)
Description: Valve linear-elliptical to linear-lanceolate, with drawn out, bluntly rounded, subrostrate to
capitate ends. Raphid valve: axial area narrow and linear, often slightly arcuate, raphe filiform. Central area
has various forms due to shortened medial striae, ranging from one or two shortened striae on either side of
the central nodule, to a wide transverse band (almost fasciate) that often reaches the margins. Transapical
striae highly dense, radial throughout the valve. Araphid valve: axial area (pseudoraphe) extremely narrow to
broad lanceolate. Central area usually absent, occasionally transverse due to shortened medial striae.
Transapical striae with same arrangement as the raphid valve. Length 10-23 (5-25) µm, width 2.5-4 (2.5-4)
µm, striae density 28 (30)/10 µm.
Key references: Foged 1978, p. 28.
Hodgson et al. 1997, p. 29.
Holland & Clark 1989, p. 9, pl. 1, figs 14-17.
John 1983, p. 74, pl. 32, figs 3, 4.
Germain 1981, p. 109, pl. 41, figs 12-19.
Krammer & Lange-Bertalot 1991, p. 56, figs 32: 1-61, 33: 1-22, 34: 1-22, 35: 1-3.
Patrick & Reimer 1966, p. 253, pl. 16, figs 9-10.
Thomas 1983, p. 19, pl. 3, fig. 10.
Vyverman et al. 1995, p. 17, pl. 7, fig. 5, pl. 23, figs 3-5, 8-9, 12.
Common varieties:
'var. inconspicua'
Syn: Navicula strenzkei Hustedt 1962
Achnanthes strenzkei (Hustedt) Simonsen 1987
Valve much shorter, almost linear-elliptical, with bluntly rounded ends.
NB: We are not aware that Achnanthes minutissima var. inconspicua has been transferred to
Achnanthidium, and therefore must be considered in the context above as an informal variety of A.
minutissimum.
'var. scotica'
Syn: Achnanthes microcephala f. scotica Carter in Carter & Bailey-Watts 1981
Valve linear to linear-lanceolate, with elongated, broadly capitate ends. Valve margins may appear
weakly undulate.
NB: We are not aware that Achnanthes minutissima var. scotica has been transferred to Achnanthidium,
and therefore must be considered in the context above as an informal variety of A. minutissimum.

11
Achnanthidium minutissimum cont.
Similar species: Achnanthes hungarica (p. 7)
Achnanthes subexigua (p. 9)
Achnanthidium affine (Grunow) Czarnecki 1994 (a previous variety of A. minutissima -
not described in this guide)
Achnanthidium altergracillima (Lange-Bertalot) Round & Bukhtiyarova 1996
(a previous variety of A. minutissima -not described in this guide)
Achnanthidium saprophila (Kobayasi & Mayama) Round & Bukhtiyarova 1996
(a previous variety of A. minutissima -not described in this guide)
Rossithidium pusillum (p. 16)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be extremely abundant,
often completely dominating an assemblage. Recorded
in epipelic and epilithic assemblages, possibly
aerophilous. Slightly sensitive to organic pollution.
The most common variety recorded is Achnanthidium
minutissimum var. minutissimum.
Fig. 6. Achnanthidium minutissimum: (a-f) raphid valves: (a) Wimmera River, VIC, x1800; (b) Bremer
River, SA, x2200; (c) Tookayerta Creek, SA, x2200; (d) Blackwood River, WA, x2200; (e) Dawesley Creek,
SA, x1950; (f) Blackwood River, WA, x2280; (g-h) girdle view: (g) Sheepwash Creek, WA, x2300; (h)
Dawesley Creek, SA, x2300.

12
Karayevia clevei
(Grunow in Cleve & Grunow) Round & Bukhtiyarova 1996 (Figs 7a-b)
Synonyms: Achnanthes clevei Grunow in Cleve & Grunow 1880
Achnanthidium clevei (Grunow in Cleve & Grunow) Czarnecki 1995
Achnanthes clevei var. rostrata Hustedt 1930
Description: Valve elliptical-lanceolate, with narrowly rounded ends. Raphid and araphid valve clearly
distinct. Raphid valve: narrow linear axial area, raphe filiform. Central area small or absent, with alternating
longer and shorter striae on either side. Striae strongly radiate and distinctly punctate. Araphid valve: narrow,
linear, axial area (pseudoraphe). Undifferentiated central area. Striae coarsely punctate, almost parallel in the
central region becoming slightly radial distally. Length 15-16 (8-32)µm, width 6 (4.5-10 )µm, (raphid valve)
striae density 16-20 (16-27)/10 µm, (araphid valve) striae density 13 (9-16)/10 µm.
Key references: Foged 1978, p. 23.
Germain 1981, p. 114, pl. 42, figs 8, 9.
Hodgson et al. 1997, p. 26.
Krammer & Lange-Bertalot 1991, p. 35, fig. 21: 1-17.
Patrick & Reimer 1966, p. 267, pl. 17, figs 21,22.
Common varieties:
'var. rostrata'
Syn: Achnanthidium clevei var. rostratum (Hustedt) Edlund 1995
Distinct protracted, rostrate ends (Patrick & Reimer, 1966).
NB: We are not aware that Achnanthes clevei var. rostrata has been transferred to Karayevia, and
therefore must be considered in the context above as an informal variety of K. clevei.
Similar species: None
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but rarely abundant. Recorded in
epipelic and epilithic assemblages.
Fig. 7. Karayevia clevei, Wild Duck Creek, VIC,
x2600; (a) raphid valve; (b) araphid valve.

13
Planothidium delicatulum
(Kützing) Round & Bukhtiyarova 1996 (Figs 8a-c)
Synonyms: Achnanthidium delicatulum Kützing 1844
Achnanthes delicatula (Kützing) Grunow in Cleve & Grunow 1880
Achnanthes delicatula subspecies hauckiana (Grunow in Cleve & Grunow) Lange-Bertalot &
Ruppel 1980
Description: Valve lanceolate-elliptical with pointed, subrostrate ends. Valve ends deflected to one side of
apical axis in larger forms. Raphid valve: narrow, linear axial area and rounded central area. Striae weakly
radial throughout valve. Araphid valve: narrow, linear axial area (pseudoraphe), central area undifferentiated.
Striae weakly radial. Length 17-18 (7-20) µm, width 6.5-8 (4-8) µm, striae density 13-14 (9-20)/10 µm.
Key references: Foged 1978, p. 24, pl. 15, figs 11a,b.
Germain 1981, p. 114, pl. 42, figs 10-15.
Hodgson et al. 1997, p. 26.
Holland & Clark 1989, p. 9, pl. 1, figs 6-8.
John 1983, p. 70, pl. 30, figs 3,4.
Krammer & Lange-Bertalot 1991, p. 70, figs 39; 1-19, 40: 1-13.
Vyverman et al. 1995, p. 14, pl. 6, fig. 4, pl. 8, fig. 3, pl. 23, figs 13-14.
Common subspecies:
subspecies hauckiana (Grunow in Cleve & Grunow) Lange-Bertalot & Ruppel 1980
Syn: Achnanthes hauckiana Grunow in Cleve & Grunow 1880
Achnanthes fonticola Hustedt 1945
Achnanthes delicatula spp. hauckiana (Grunow in Cleve & Grunow)
Lange-Bertalot & Ruppel 1980
Valves elliptical to elliptical-lanceolate, ends broadly rounded.
Similar species: Planothidium lanceolatum (araphid valve) (p. 15)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread, common in urban streams, can be
abundant. Recorded in epipelic and epilithic
assemblages. Occurs across a broad range of
ecological conditions and, as such, is a poor indicator
species.
Fig. 8. Planothidium delicatulum: (a) raphid
valve, Mount Barker Creek, SA, x2200; (b-c)
araphid valves: (b) Echunga Creek, SA, x2200;
(c) Dawesley Creek, SA, x2100.

14
Planothidium frequentissimum
(Lange-Bertalot) Round & Bukhtiyarova 1996 (Figs 9a-g)
Synonyms: Achnanthes lanceolata var. dubia f. minuta Grun. in Van Heurck 1880-1887
Achnanthes lanceolata var. frequentissima Lange-Bertalot 1991
Description: Valves widely elliptical to elliptical-lanceolate and lanceolate, with widely rounded ends.
Raphid and araphid valves clearly distinct. Raphid valve: axial area narrow and linear, raphe filiform and
straight. Central area broadly transverse, rectangular. Striae radial throughout the valve. Araphid valve: axial
area narrow to broad lanceolate. Central area distinctly one-sided, appearing as a complete, distinct,
depressed, horseshoe-shaped clear area which extends to the valve margin. Striae weakly radial throughout
the valve. Length 11-22 (6-40) µm, width 5-7 (4.5-10) µm, striae density 10-14 (10-15)/10 µm.
Key references: Foged 1978, p. 26, pl. 15, figs 4, 5, 7, 8.
Germain 1981, p. 115, pl. 44, figs 1-18.
Hodgson et al.1997, p. 28, pl. 4, figs 6, 7, 15, 16, pl. 6, fig. 28.
Holland & Clark 1989, p. 9, pl. 1, figs 9, 10.
John 1983, p. 73, pl. 31, figs 13-16.
Krammer & Lange-Bertalot 1991, p. 75, figs 41: 1-25, 42: 1-8, 43: 1-40, 44: 1-38.
Patrick & Reimer 1966, p. 269, pl. 18, figs 1-21.
Similar species: Planothidium lanceolatum (Brébisson) Round & Bukhtiyarova 1996 (p. 15)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and frequently abundant in
streams subject to nutrient and / or organic pollution.
Recorded in epipelic and epilithic assemblages.
Fig. 9. Planothidium frequentissimum: (a-c) raphid valves; Dandenong Creek, VIC, x2300; (d-g) araphid
valves; (d) Dandenong Creek, VIC, x2300; (e) Surrey River, VIC, x2090; (f) Surrey River, VIC, x2090; (g)
Adelong River, NSW, x2100.

15
Planothidium lanceolatum
(Brébisson) Round & Bukhtiyarova 1996 (Figs 10a-d)
Synonyms: Achnanthes lanceolata (Brébisson) Grunow in Cleve & Grunow 1880
Achnanthidium lanceolatum (Brébisson) Grunow in Cleve & Grunow 1880
(Achnanthidium lanceolata (Brébisson) Grunow sensu Gell et al 1999)
Description: Valve shape extremely variable, elliptical, rhomboid-elliptical to lanceolate elliptical, with
broadly rounded, subcapitate, capitate or drawn out, sharply rounded, subrostrate ends. Raphid and araphid
valves clearly distinct. Raphid valve: axial area narrow and linear, raphe filiform and straight. Central area
broadened transversely, rectangular. Striae radial throughout the valve. Araphid valve: axial area narrow to
broad lanceolate. Central area distinctly one-sided, appearing as a horseshoe-shaped, depressed, clear area
which extends to the valve margin. Striae weakly radial throughout the valve. Length 23-27 (6-40) µm,
width 6-7 (4.5-10) µm, striae density 12 (10-15)/10 µm.
Key references: Foged 1978, p. 26, pl. 15, figs 4, 5, 7, 8.
Germain 1981, p. 115, pl. 44, figs 1-18.
Hodgson et al. 1997, p. 28, pl. 4, figs 6, 7, 15, 16, pl. 6, fig. 28.
Holland & Clark 1989, p. 9, pl. 1, figs 9, 10.
John 1983, p. 73, pl. 31, figs 13-16.
Krammer & Lange-Bertalot 1991, p. 75, figs 41: 1-25, 42: 1-8, 43: 1-40, 44: 1-38.
Patrick & Reimer 1966, p. 269, pl. 18, figs 1-21.
Similar species: Planothidium frequentissimum (p. 14)
Planothidium delicatulum (raphid valve) (p. 13)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and frequently abundant.
Recorded in epipelic and epilithic assemblages.
Generally found in waters of lower nutrient
concentrations than P. frequentissima though the two
can co-occur.
Fig. 10. Planothidium lanceolatum: (a-b)
raphid valves: (a) Surrey River, VIC,
x2090; (b) Surrey River, VIC, x2040; (c-
d) araphid valves; (c) Surrey River, VIC,
x2040; (d) Dandenong Creek, VIC,
x2200.

16
Rossithidium pusillum
(Grunow) Round & Bukhtiyarova 1996 (Figs 11a-e)
Synonyms: Achnanthes linearis var. pusilla Grunow in Cleve & Grunow 1880
Achnanthes pusilla (Grunow) De Toni 1891
Achnanthidium pusillum (Grunow) Czarneki 1995
Description: Valve linear to linear-elliptical with broadly rounded ends. Raphid valve: axial area narrow
and linear, raphe filiform. Central area widely transverse, formed by one or two slightly shortened and more
widely spaced medial striae. Transapical striae weakly radial throughout the valve. Araphid valve: axial area
(pseudoraphe) narrowly linear to slightly lanceolate. Central area absent, although medial striae may be
arranged irregularly. Transapical striae with same arrrangement as the raphid valve. Length 11-16
(8.5-18) µm, width 3-3.5 (3.5-4.5) µm, striae density 22-24 (18-23)/10 µm.
Key references: Krammer & Lange-Bertalot 1991, p. 67, fig. 37: 9-18.
Patrick & Reimer 1966, p. 252, pl. 16, figs 5, 6.
Common varieties: None
Similar species: Achnanthes hungarica (p. 7)
Achnanthidium minutissimum (p. 10)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread in alpine areas. Mostly recorded in
epilithic assemblages. Largely confined to waters with
low nutrient and ionic concentrations.
Fig. 11. Rossithidium pusillum, Sevens Creeks, VIC, x3300; (a-b) raphid valves; (c-e) araphid valves.

17
Actinocyclus normanii
(Gregory) Hustedt 1967 (Figs 12a-b)
Synonyms: Refer to individual variety descriptions.
Description: Cell shallow disc shaped. Valve face circular, slightly undulate and ornamented with rows of
areolae arranged radially. Areolae form wedge shaped patterns called fascicles. Valve margin ornamented
with smaller areolae. Valve also with a single isolated pseudonodulus (small hole through the valve face) on
the valve margin. Diameter 16-20 (16-110) µm.
Key references: John 1983, p. 28, pl. IX, figs 6-9.
Krammer & Lange-Bertalot 1991, p. 88, figs: 80: 3-5, 81: 1-5, 82: 1-7.
Common varieties:
var. normanii
Syn: Coscinodiscus normanii Gregory ex Greville 1859
Nominate variety, refer to description above.
var. subsalsus (Juhlin-Dannfelt) Hustedt 1957
Syn: Coscinodiscus subsalsus Juhlin-Dannfelt 1882
Coscinodiscus subtilis var. fluviatilis (Gregory) Van Heurck 1885
Coscinodiscus rothii var. subsalsum (Juhlin-Dannfelt) Hustedt 1928
Valves smaller, diameter generally less than 60 mm.
Similar species: Large Aulacoseira species (pp. 23-24)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: A. normanii var. subsalsus is widepsread in
lowland, slow flowing streams but not usually
abundant. Planktonic taxon but can be found in
epipelic and epilithic assemblages.
Fig. 12. Actinocyclus normanii var subsalsus: (a-b) Loddon River, VIC, x2250.

18
Genus Amphora
Key to the common species
1a. Dorsal side of valve with hyaline (clear) area above proximal raphe ends ........................................... 2
1b. No area evident ................................................................................................................................... 3
2a. Valve small (< 5 mm wide); raphe ±straight ........................................................... Amphora pediculus
2b. Valve larger (> 5 mm wide); raphe clearly arched ......................................................... Amphora libyca
3a. Dorsal striae clearly more widely spaced near centre ................................................... Amphora veneta
3b. Dorsal striae appear more equally spaced ......................................................... Amphora coffeaeformis
Amphora coffeaeformis
(Agardh) Kützing 1844 (Figs 13a-d)
Synonyms: Refer to individual species descriptions
Description: Valve semi-lanceolate, with convex dorsal margin and straight to slightly concave ventral
margin. Valve generally narrowly elongate, with drawn out, rostrate to capitate ends. Numerous intercalary
bands usually present on the dorsal side. Axial area narrow and linear, wide on the ventral side, narrow on
the dorsal side, located close to the ventral margin. Raphe straight and filiform, proximal ends close together
and slightly deflected dorsally. Central area one-sided, extending to the ventral margin due to an interruption
in the ventral striae. Absent on the dorsal side. Dorsal striae parallel to weakly radial, slightly more widely
spaced in the centre than at the ends. Ventral striae appear as short marginal dashes (often as single punctae),
which are often difficult to distinguish under LM. Length 25-31 (13-60) µm, width 5 (10-19) µm, striae
density (centre) 18-19 (17-26)/10 µm, striae density (ends) (20-30)/10 µm.
Key references: Germain 1981, p. 296, pl. 109, figs 8, 9.
Hodgson et al. 1997, p. 34.
John 1983, p. 149, pl. 61, figs 8-11.
Krammer & Lange-Bertalot 1986, p. 347, fig. 151: 1-6.
Vyverman et al. 1995, p. 24.

19
Amphora coffeaeformis cont.
Common varieties:
var. coffeaeformis
Syn: Frustulia coffeaeformis Agardh 1827
Amphora salina W. Smith 1853
Nominate variety, description above.
var. acutiscula (Kützing) Rabenhorst 1864
Syn: Amphora acutiscula Kützing 1844
Raphe more dorsally positioned. Striae highly punctate, with parallel, hyaline, longitudinal band on the
dorsal side.
var. borealis (Kützing) Cleve 1896
Generally smaller, with noticeably punctate striae.
Similar species: Amphora veneta (p. 22)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but rarely abundant. Confined to
high conductivity waters. Mostly recorded in epipelic
assemblages.
Fig. 13. Amphora coffeaeformis: (a) Wild Dog Creek, SA, x2250; (b) Hopkins River, VIC, x2300; (c)
Hopkins River, VIC, x2300; (d) Amphora coffeaeformis var. borealis, Salt Creek, SA, x2200.

20
Amphora libyca
Ehrenberg 1840 (Fig. 14)
Synonyms: Amphora affinis Kützing 1844
Amphora ovalis var. affinis (Kützing) Van Heurck 1880
Amphora ovalis var. libyca (Ehrenberg) Cleve 1895
Amphora ovalis var. pediculus (Kützing) Cleve 1895
Description: Valve dorsi-ventral, more or less lunate, with smooth, convex dorsal margin and weakly
concave ventral margin. Valve ends acutely rounded. Intercalary bands absent. Axial area narrow and linear,
weakly arched dorsally either side of the valve centre. Raphe filiform, dorsally arched, with proximal ends
deflected dorsally and distal ends deflected ventrally. Central area prominent, extending onto the dorsal
surface as a rectangular to circular hyaline area, and to the ventral margin due to an interuption in the ventral
striae. Dorsal striae weakly radial throughout, ventral striae radial in the centre becoming parallel to
convergent at the ends. Striae coarsely punctate. Length 27-39 (20-80) µm, width 7-12 (14-35) µm, striae
density 14-15 (11-15)/10 µm.
Key references: Foged 1978, p. 33, pl. 36, fig. 11.
Hodgson et al. 1997, p. 35, pl. 5, figs 1, 2.
John 1983, p. 152, pl. 62, figs 11, 12.
Krammer & Lange-Bertalot 1986, p. 345, fig. 149: 3-11.
Patrick & Reimer 1975, p. 69, pl. 13, figs 3, 4.
Common varieties: None
Similar species: Amphora pediculus (p. 21)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but generally not abundant. A
heavily silicified frustule. Recorded mostly in epilithic
assemblages but also found on the epipelon.
Fig. 14. Amphora libyca, Ovens River, VIC, x2300.

21
Amphora pediculus
(Kützing) Grunow ex A. Schmidt 1875 (Figs 15a-c)
Synonyms: Cymbella pediculus Kützing 1844
Amphora ovalis var. pediculus (Kützing) Van Heurck 1885
Amphora perpusilla Grunow sensu Patrick & Reimer 1975
Description: Valve lunate/semi-elliptical, with convex dorsal margin, and straight to sometimes slightly
concave ventral margin. Valve ends subacute to smoothly rounded. Axial area narrow and straight, located
close to the ventral margin. Proximal raphe ends deflected to the dorsal side. Central area broad, extending
dorsally as a rectangular blank space, fully extending ventrally to the margin. Dorsal striae often coarsely
punctate, parallel to slightly radial, becoming more dense towards the ends. Ventral striae absent opposite the
central area, radial in the centre, convergent distally. Length 10-14 (5-18) µm, width 3 (2-4) µm, striae
density 16 (18-25)/10 µm.
Key references: Foged 1978, p. 34.
Germain 1981, p. 295, pl. 108, figs 3-5.
Holland & Clark 1989, p. 10, pl. 1, fig. 23.
John 1983, p. 153, pl. 62, figs 13, 14.
Krammer & Lange-Bertalot 1986, p. 346, fig. 150: 8-13.
Patrick & Reimer 1975, p. 69, pl. 13, figs 5, 6.
Common varieties: None
Similar species: Amphora veneta (p. 22)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be very abundant.
Recorded mostly in epilithic assemblages. Valves are
often in girdle view with both valves attached.
Moderate to high tolerance of both high electrical
conductivities and TP.
Fig. 15 Amphora pediculus, Jacksons Creek, VIC,
x3500.

22
Amphora veneta
Kützing 1844 (Figs 16a-d)
Synonyms: Amphora gouwsii Cholnoky 1953
Description: Valve crescent shaped, ventral margin straight to slightly concave, with ventrally turned,
drawn out, capitate to truncate ends. Axial area slightly convex, broader on the ventral side. Raphe filiform,
sinuous, and close to the ventral margin. Striae punctate and radial. Dorsal central striae more widely spaced
and noticeably punctate. Ventral striae appearing marginal or not at all. Length 17-28 (5-60) µm, width 5-6
(7-18) µm, striae density (ends) 24-26 (26-32)/10 µm, striae density (central area) 18 (16-26)/10 µm.
Key references: Foged 1978, p. 34, pl. 36, figs 7, 8.
Hodgson et al. 1997, p. 36, pl. 4, fig. 19.
Holland & Clark 1989, p. 10, pl. 1, figs 19, 20.
John 1983, p. 157, pl. 66, figs 3-5.
Krammer & Lange-Bertalot 1986, p. 348, fig. 151: 7-17.
Patrick & Reimer 1975, p. 72, pl. 14, figs 2-3.
Vyverman et al. 1995, p. 24, pl. 13, fig. 1, pl. 35, figs 1-3.
Common varieties: None
Similar species: Amphora coffeaeformis (p. 18)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and occasionally abundant. Mostly
recorded in epipelic assemblages. Tolerant of organic
pollution.
Fig. 16. Amphora veneta: (a) Deep Ck, VIC, x2100;
(b) Warren River, WA, x2020; (c) Plenty River, VIC,
x2100; (d) Genoa River, VIC, x1900.

23
Genus Aulacoseira
Key to the common species
1a. Valve height ³diameter; pervalvar striae > 22/10 mm ................. Aulacoseira subarctica f. subborealis
1b. Valve height usually >diameter; valve mantle more coarsely areolate ................................................. 2
2a. Valves with an internal canal (sulcus) at junction between the mantle and the valve surface; pervalvar
striae and areolae > 15/10 mm; linking spines short and not prominent ................. Aulacoseira ambigua
2b. No canal visible, although an indistinct “sulcus” (pseudosulcus) may be present; areolae usually more
coarsely distributed. ............................................................................................................................ 3
3a. ‘Separation’ cells1present in population (the proportion may vary from around 10% up to around 30%);
linking spines usually not prominent ................................................................................................... 4
3b. No ‘separation’ cells in population; linking spines usually prominent .....................................................
............................................................................................. Other species not included in this guide2
4a. Valves > 4 mm; mantle height : diameter < 5:1; pervalvar striae and areolae usually < 10/10 mm
(although densities of up to 15/10 mm may occur) ............................................. Aulacoseira granulata
4b. Valves < 4 mm in diameter; mantle height : diameter up to 10:1; pervalvar striae and areolae > 12/10 mm
...............................................................................................................................................................
............................................................................................. Aulacoseira granulata var. angustissima
Aulacoseira ambigua
(Grunow) Simonsen 1979 (Figs 17a-d)
Synonyms: Melosira crenulata var. ambigua Grunow in Van Heurck 1882
Melosira ambigua (Grunow) O. Müller 1903
Description: Cell cylindrical. Valve mantle width and length extremely variable. Valve face finely punctate,
mantle margin with a row of bifid connection spines that interlock with an adjacent valve. Valve mantle
ornamented with spiralling rows of pervalvar striae, diagonal to the pervalvar axis. Striae coarsely areolate.
Valve with an internal canal at the junction of the mantle and the pervalvar surface, which, when using phase
contrast or DIC, appears as a distinct 'pore' on either side of the valve mantle margin (when focusing through
the valve). Cells forming long chains up to ten cells long. Valve diameter 6.5-8 (4-17) µm, valve mantle
height 8-9 (5-13) µm, pervalvar striae density 18 (16-25)/10 µm, areolae (17-22)/10 µm.
Key references: Germain 1981, p. 26, pl. 4, figs 5-7.
Krammer & Lange-Bertalot 1991, p. 25, figs 1:5, 2: 3, 21: 1-16.
Common varieties: None
Similar species: Aulacoseira granulata (p. 24)
Aulacoseira subartica (p. 26)
1Separation cells are distinguished from normal cells by the presence of long (up to the length of the valve mantle)
spines and corresponding grooves along the valve mantle and by the alignment of areolae in more or less straight lines
along the mantle (as opposed to the spiraling arrangement found on normal cells)
2Several other species of Aulacoseira may be encountered. Most have prominent linking spines (A. italica, A.
crenulata, A. valida) -see Krammer and Lange -Bertalot (1991a)

24
Aulacoseira ambigua cont.
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread in lowland, slow flowing rivers.
Planktonic taxon but can be deposited in epipelic and
epilithic habitats. Abundant in the Murray River and
can be confused with Aulacoseira granulata.
Fig. 17. Aulacoseira ambigua: (a) Mullaroo Creek, VIC, x2300; (b) Goulburn River, VIC, x2150; (c)
Torrens River, SA, x2400; (d) Torrens River, SA, x2150.
Aulacoseira granulata
(Ehrenberg) Simonsen 1979 (Figs 18a-e)
Synonyms: Refer to individual variety descriptions.
Description: Cell cylindrical. Valve face flat with randomly arranged punctae, mantle margin with a row of
connection spines that interlock with spines of the adjacent valve. Valve with deep mantle ornamented with
spiralling rows of pervalvar striae, diagonal to the pervalvar axis. Connection cells with a conspicuously
elongate connecting spine and with striae parallel to the pervalvar axis. Striae coarsely areolate. Cells
regularly forming long filamentous chains. Valve diameter 2.5-5 (4-30) µm, valve mantle height 9.5-13.5 (5-
24) µm, pervalvar striae density 6-15 (7-10)/10 µm, areolae 8-16 (5-9)/10 µm.
Key references: Foged 1978, p. 81, pl. 1, figs. 4-7, 9.
Germain 1981, p. 24, pl. 3, figs 1-6.
Holland & Clark 1989, p. 18, pl. 14, figs 1-5.
John 1983, p. 14, pl. 1, figs 3-5.
Krammer & Lange-Bertalot 1991, p. 22, figs 16: 1, 2, 17: 1-10, 18: 1-14, 19: 1-9.
Thomas 1983, p. 47, pl. 2, figs 7-15.
Vyverman et al. 1995, p. 25.

25
Aulacoseira granulata cont.
Common varieties:
var. granulata
Syn: Gallionella granulata Ehrenberg 1843
Gallionella decussata Ehrenberg 1843
Orthosira punctata W. Smith 1856
Melosira granulata (Ehrenberg) Ralfs in Pritchard 1861
Melosira lineolata Grunow in Van Heurck 1881
Nominate variety, description as above.
var. angustissima (O. Müller) Simonsen 1979
Syn: Melosira granulata var. angustissima O. Müller
Valve extremely narrow, length:width ratio relatively higher, up to 10 (Krammer & Lange-Bertalot,
1991). Striae more finely areolate. Cells forming curved filaments.
Similar species: Aulacoseira ambigua (p. 23)
Aulacoseira italica (Ehrenberg) Simonsen 1979 (not described in this guide)
Aulacoseira subarctica (p. 26)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread in lowland, slow flowing rivers.
Planktonic taxon but can be deposited in epipelic and
epilithic habitats. Valves can be very variable. Seems
to prefer turbulent environments.
Fig. 18. Aulacoseira granulata, Loddon River, VIC; (a-b) separation cells, x2000; (c-d) x2100.

26
Aulacoseira subarctica
(O. Müller) Haworth 1988 (Figs 19a-c)
Synonyms: Refer to individual variety and form descriptions.
Description: Cell cylindrical. The valve face is finely punctate, often restricted to the margins. Clearly
defined ringleiste can be seen in valve view.. Valve mantle margin with a row of short connection spines
emerging from two pervalvar striae, interlocking with the adjacent valve. Valve mantles relatively short
(Valve mostly appearing squat) and ornamented with spiralling rows of highly dense pervalvar striae,
diagonal to the pervalvar axis. Striae finely areolate. Valve diameter 5-6.5 (3-15) µm, valve mantle height
2.5-4 (2.5-18) µm, pervalvar striae density 20-30 (17-21)/10 µm, areolae density 18-30 (17-22)/10 µm.
Key references: Krammer & Lange-Bertalot 1991, p. 28, figs 2: 1, 3: 3, 23: 1-11.
Common varieties and forms:
var. subarctica
Syn: Melosira italica subsp. subartica O. Müller 1906
Aulacoseira italica subspecies subartica (O. Müller) Simonsen 1979
Nominate variety, description above. Very similar to A. granulata in length and width.
var. subarctica f. subborealis Nygaard 1966
Cells appearing more squat.
Similar species: Aulacoseira ambigua (p. 23)
Aulacoseira granulata (p. 24)
Aulacoseira italica (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but not as abundant as A. ambigua
and A. granulata. Planktonic taxon but can be
deposited in epipelic and epilithic habitats. Valves can
be very variable. Form subborealis is the most
common variety, the nominate form is rarely
encountered.
Fig. 19. Aulacoseira subartica f. subborealis, Murray River, Mildura, VIC; (a) x2600; (b) x2000; (c) valve
view, x2600.

27
Bacillaria paxillifer
(Müller) Hendey 1951(Figs 20a-b)
Synonyms: Vibrio paxillifer Müller 1786
Nitzschia paradoxa (Müller) Grunow 1880
Bacillaria paradoxa Gmelin 1791
Description: Valve linear to linear-lanceolate (spindle-shaped), with drawn out rostrate or capitate ends.
Raphe canal central to eccentric, with conspicuous, irregularly spaced fibulae which convey a 'ladder'
appearance. Striae punctate and parallel. Punctae difficult to distinguish under LM. Cells are often arranged
in linear colonies via attachment of the raphe. Length 64-75 (60-150) µm, width 5.5-6 (4-8) µm, fibulae
density (5-9)/10 µm, striae density 22-23(20-25)/10 µm.
Key references: Foged 1978, p. 36, pl. 46, fig. 1.
Holland & Clark 1989, p. 10. pl. 2, figs 7, 8, 13.
John 1983, p. 163, pl. 68, figs 4, 5.
Krammer & Lange-Bertalot 1988, p. 8, fig. 87: 4-7.
Common varieties: None
Similar species: Nitzschia dissipata (p. 110)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be very abundant. Can
sometimes be planktonic but mostly recorded in
epipelic and epilithic assemblages. Very tolerant of
high nutrient concentrations. Unique gliding motion
when live colonies are viewed (often forming a zigzag
pattern).
Fig. 20. Bacillaria paxillifer: (a) Gardiners Creek, VIC, x2000; (b) Loddon River, VIC, x2200.

28
Cocconeis placentula
Ehrenberg 1838 (Figs 21a-e)
Synonyms: Refer to individual variety descriptions.
Description: Valve elliptical, sometimes tending towards linear-elliptical. Valve flat or slightly arched.
Raphid and araphid valves clearly distinct. Raphid valve: axial area narrow and straight, with a small oval
central area. Proximal raphe ends located very close to each other. Striae finely punctate, radial, increasingly
radial distally. Striae interupted near the valve margin by a longitudinal hyaline area. Araphid valve: narrow
pseudoraphe, striae radial and punctae. Punctae forming many longitudinal, undulate lines on the valve face.
Length 24-41(7.5-98) µm, width 11-24 (8-40) µm, striae density (raphid valve) 20-22 (20-23)/10 µm, striae
density (araphid valve) 18-20 (24-26)/10 µm.
Key references: Foged 1978, p. 42, pl. 13, figs. 5, 7-9.
Germain 1981, p. 102, pl. 38-39.
Hodgson et al. 1997, p. 41, pl. 6, fig. 1.
Holland & Clark 1989, p. 11, pl. 3, figs 1-6.
John 1983, p. 79, pl. 34, figs 11, 12, pl. 35, fig. 1.
Krammer & Lange-Bertalot 1991, p. 86, figs 49: 1-4, 50: 1, 2, 5, 51: 1-9, 52; 1-13, 54:
1-12.
Patrick & Reimer 1966, p. 240, pl. 15, fig. 7.
Thomas 1983, p. 24, pl. 3, figs 19-21.
Vyverman et al. 1995, p. 31.
Common varieties:
var. placentula
Syn: Cocconeis punctata Ehrenberg 1841
Cocconeis elongata Ehrenberg 1841
Cocconeis pumila Kützing 1844.
Nominate variety, description as above.
var. euglypta (Ehrenberg) Grunow 1884
Syn: Cocconeis euglypta Ehrenberg 1854
Striae density on the araphid valve much coarser than nominate variety, punctae forming 2-4
conspicuous, longitudinal, hyaline lines.
var. lineata (Ehrenberg) Van Heurck 1880-1885
Syn: Cocconeis lineata Ehrenberg 1843
Striae density on the araphid valve coarser than var. placentula but less coarse than var. euglypta,
punctae forming up to 10-12 longitudinal, hyaline lines.
Similar species: Navicula cocconeiformis Gregory ex Greville 1856 (Not described in this guide)
Navicula pseudoscutiformis Hustedt 1930 (Not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and very abundant, often
competely dominating a sample, particularly
artificial substrates. Found in circumneutral to
alkaline waters in a range of conductivities.

29
Cocconeis placentula cont.
Fig. 21. Cocconeis placentula: (a) Dandenong Creek, VIC, x1650; (b) Surrey River, VIC, x2200; (c)
Tookayerta Creek, SA, x1700; (d) Gardiners Creek, VIC, x1600; (e-f) Goulburn River, VIC, x2100.

30
Genus Craticula
Key to the common species
1a. Valve elliptical lanceolate; central striae more widely spaced .................................Craticula accomoda
1b. Valve lanceolate; striae appear evenly spaced throughout ....................................... Craticula halophila
Craticula accomoda
(Hustedt) Mann 1990 (Fig. 22)
Synonyms: Navicula accomoda Hustedt 1950
Description: Valve lanceolate to elliptical-lanceolate, with short, narrow, rostrate to sub-capitate ends. Axial
area narrow, raphe filiform and straight. Proximal raphe ends distant from each other, distal raphe ends
curved to the same side. Central area indistinct, slightly transapically widened. Striae almost parallel and
more widely spaced at the centre, becoming more dense and slightly convergent distally. Longitudinal lines
close to the valve margins may be occasionally present. Length 18-23 (17-25) µm, width 5-7.5 (4.5-11.5)
µm, striae density (centre) 18-21 (17-25)/10 µm, striae density (distally) (20-28)/10 µm.
Key references: Foged 1978, p. 83.
Germain 1981, p. 170, pl. 63, fig. 5.
Patrick & Reimer 1966, p. 468, pl. 44, fig. 7.
Krammer & Lange-Bertalot 1986, p. 128, fig. 45: 13-20.
Common varieties: None
Similar species: Craticula halophila (p. 31)
Navicula gregaria (p. 91)
Navicula molestiformis (p. 95)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but rarely abundant. Recorded in
both epipelic and epilithic assemblages. Presence in
moderate to high abundances can indicate organic
pollution.
Fig. 22. Craticula accomoda, Dawesley Creek, SA, x2100.

31
Craticula halophila
(Grunow ex Van Heurck) Mann 1990 (Figs 23a-b)
Synonyms: Navicula cuspidata var. halophila Grunow in Van Heurck 1885
Navicula halophila (Grunow ex Van Heurck) Cleve 1894
Description: Valve rhomboid to rhomboid-lanceolate, usually drawn out, acute, rounded to subcapitate
ends. Axial area narrow, raphe filiform to broad, and straight. Central area indistinct, occasionally
transapically widened. Transapical striae parallel to sometimes slightly radial in the centre, generally
becoming convergent distally. Fine longitudinal lines may be present. Length 26-29 (7-140) µm, width 7.5-8
(4.5-18) µm, striae density 18-22 (15-24)/10 µm.
Key references: Foged 1978, pl. 27, figs. 5, 7.
Germain 1981, p. 172, pl. 65.
Patrick & Reimer 1966, p. 467, pl. 44, figs 4, 5.
Krammer & Lange-Bertalot 1986, p. 126, figs 44: 1-11, 14-18, 43: 9.
Common varieties: None
Similar species: Craticula accomoda (p. 30 )
Navicula gregaria (p. 91)
Navicula molestiformis (p. 95)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but not usually abundant.
Recorded in both epipelic and epilithic
assemblages. Large specimens may be confused
with Craticula cuspidata (not described in this
guide). This taxon is polymorphic and may
comprise several species.
Fig. 23. Craticula halophila: (a) Heathfield Stream, SA, x2350; (b) Dawesley Creek, SA, x2230.

32
Ctenophora pulchella
(Ralfs ex Kützing) Williams & Round 1986 (Figs 24a-c)
Synonyms: Synedra pulchella Ralfs ex Kützing 1844
Exilaria pulchella Ralfs ex Kützing 1844
Synedra familiaris Kützing 1844
Fragilaria pulchella (Ralfs ex Kützing) Lange-Bertalot 1980
Description: Valve linear-lanceolate with broadly rounded to attenuated sub-capitate ends. Axial area
(pseudoraphe) narrow and straight, occasionally widened towards the central region, generally not visible.
Central area large, rectangular to circular in shape, extending to the valve margins and often swollen laterally
to form a central 'nodule'. Transapical striae distinctly punctate, parallel in the central region, sometimes
becoming slightly radial at the valve ends. Length 28-181 (20-200) µm, width 5-7 (5-8.5) µm, striae density
12-14 (9-17)/10 µm.
Key references: Foged 1978, p. 131, pl. 8, figs 21, 22, pl. 9, fig. 4.
Germain 1981, p. 78, pl. 26, figs 1-4.
Hodgson et al. 1997, p. 74.
Holland & Clark 1989, p. 27, pl. 25, fig. 3, pl. 26, fig. 2.
John 1983, p. 61, pl. 25, figs 9-15.
Patrick & Reimer 1966, p. 146, pl. 6, figs 10-14.
Krammer & Lange-Bertalot 1991, p. 148, pl. 136, figs 1-7.
Common varieties: None
Similar species: Fragilaria capucina (p. 61)
Synedra acus (p. 148)
Syndra ulna (p. 149)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and may be moderately abundant.
Can be planktonic but also lives in epipelic and
epilithic assemblages. A very distinctive valve.
Fig. 24. Ctenophora pulchella: (a) Blackwood River, WA, x1330; (b-c) Deep Creek, VIC, x1500.

33
'Cyclostephanoid' group
Description: Cells disc shaped. Valve face flat or concentrically undulate, mantle shallow. A single row of
spines is present around the valve margin. A row of fultoportulae is present on the valve margin below the
spines. Valve face ornamented with radial rows of small areolae. Cells solitary or as short chains. It is
difficult to separate species within the Cyclostephanoid group owing to their small size and the high
resolution required to distinguish the diagnostic features. The taxa presented here are the most commonly
encountered; however, there are several other similar taxa and caution is advised in species identification.
Useful taxonomic references include: Kobayasi & Kobayasi (1987), Hakansson & Locker (1981), Stoermer
et al. (1988), Theriot et al. (1988).
Included in the key are three of the most common Cyclostephanoid species found in SE Australian streams:
Cyclostephanos tholiformis, Stephanodiscus hantzschii and Stephanodiscus parvus. The key features of each
species are given below.
Genera Cyclostephanos and Stephanodiscus
Key to the common species
1a. Valve margins with distinct, large spines ..................................................... Stephanodiscus hantzschii
1b. Valve margins with small or indistinguishable spines .......................................................................... 2
2a. Valve face clearly flat even for large specimens. Spines often visible, but not protruding outside the
valve margin. Fascicle (‘striae’) density mostly < 13/10 mm .............................. Stephanodiscus parvus
2b. Valve face undulate (with centre appearing raised or depressed), although this may not be apparent in
smaller specimens. Fascicle (‘striae’) density mostly > 13/10 mm ............... Cyclostephanos tholiformis
Cyclostephanos tholiformis
Stoermer, Hakansson & Theriot 1987 (Fig. 25)
Synonyms: None
Description: Valve face generally concentrically undulate, with conspicuous, eccentric fultoportula. Rows
of fine areolae arranged into fascicles. Marginal row of spines at ends of interfascicles. Interfascicles ±
branched marginally. Diameter 5.5-12.5 (7-12) µm, fascicle density 11.5-16/10 µm.
Key references: Krammer & Lange-Bertalot 1991, p. 64, fig. 67: 6a, b.
Similar species: Stephanodiscus minutulus (not described in this guide)
Stephanodiscus parvus (p. 35)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Planktonic taxon which may also be found in
epipelic assemblages. Generally characterised as a
eutrophic diatom likely to occur in lowland river
plankton but not usually as abundant as species of
Aulacoseira.

34
Cyclostephanos tholiformis cont.
Fig. 25. Cyclostephanos tholiformis, Murrumbidgee River, NSW, x2400.
Stephanodiscus hantzschii
Grunow in Cleve & Grunow 1880 (Figs 26a-c)
Synonyms: Stephanodiscus hantzschianus Grunow in Van Heurck 1881
Stephanodiscus zachariasii Brun 1894
Stephanodiscus pusillus (Grunow) Krieger 1927
Description: Valve face flat to slightly undulate, no fultoportula present. Rows of areolae arranged into
fascicles. Fasicle appearance ranges from straight to notably “wavy”. Marginal row of spines at ends of
interfascicles, except for one which ends with a rimoportula. Central area may have a distinct annulus or
ring. Valve diameter 9-10.5 (5-30) µm. Fascicle density 9-12 (8-12)/10 µm.
Key references: Hodgson et al. 1997, p. 111, pl. 2, fig. 8.
Krammer & Lange-Bertalot 1991, p. 73, figs 75: 4-11, 76: 1-3.
Similar species: Cyclostephanos invisitatus (not described in this guide)
Stephanodiscus parvus (p. 35)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Similar ecology to Cyclostephanos tholiformis.
Often dominates the plankton in European lowland
rivers (Reynolds, 1988), however, it does not appear to
be as common in SE Australian rivers. Generally less
common than S. parvus and C. tholiformis.
Fig. 26. Stephanodiscus cf. hantzschii: (a) Mullaroo Creek, VIC, x2100; (b) Mooki River, NSW, x2100; (c)
Murrumbidgee River, NSW, x2100.

35
Stephanodiscus parvus
Stoermer & Hakansson 1984 (Figs 27a-b)
Synonyms: Stephanodiscus hantzschii f. parva Grunow ex Cleve & Möller 1879
Description:Valve face flat to slightly undulate, with distinct, eccentric fultoportula. Rows of areolae
arranged into fascicles. Marginal row of short spines at ends of interfascicles. Valve diameter 5-5.5 (5-11)
µm. Fascicle density 10-16 (13-15)/10 µm.
Key references: Krammer & Lange-Bertalot 1991, p. 71, fig. 74: 1-4.
Similar species: Stephanodiscus hantzschii (p. 34)
Stephanodiscus minutulus (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Similar ecology to Cyclostephanous
tholiformis.
Fig. 27. Stephanodiscus parvus: (a) Ovens River, SA, x1500; (b) Loddon River, VIC, x1600.
Genus Cyclotella
Key to the common species
1a. Centre of valve with a large pore surrounded by radially arranged areolae forming a distinct ‘rosette’
structure .............................................................................................................................................. 2
1b. Centre of valve otherwise formed ........................................................................................................ 3
2a. Radial striae ending at margin with an indistinct bifurcation associated with marginal spines, often
difficult to discern with LM ....................................................................... Cyclotella pseudostelligera
2b. No marginal spines, radial striae not bifurcating at the margins .............................. Cyclotella stelligera
3a. Central area of valve face with no distinct ornamentation, although indistinct striations may be apparent.
Valve face of larger specimens usually distinctly undulate. At least one fultoportulae (punctae) should
be visible ...................................................................................................... Cyclotella meneghiniana
3b. Valve without that combination of features ............................ Other species not included in this guide

36
Cyclotella meneghiniana
Kützing 1844 (Figs 28a-d)
Synonyms: Surirella melosiroides Meneghini 1844
Cyclotella rectangula Brébisson ex Rabenhorst 1853
Cyclotella kuetzingiana Thwaites 1848
Description: Cell disc or drum-shaped, with a circular valve face and shallow mantle. The valve face with
conspicuous marginal zone of radially arranged areolae, extending inwards for almost 25-40% of the radius.
The areolae grouped into fascicles, creating a ridge-like appearance around the margin of the valve face. The
centre of valve structureless, with a slight undulation (not obvious in smaller specimens). Valve face with
one to two prominent fultoportulae. Valve diameter 8-21(5-43) µm, marginal fascicles (6-10)/10 µm.
Key references: Foged 1978, p. 44, pl. 2, figs 1-3.
Hodgson et al. 1997, p. 45.
Holland & Clark 1989, p. 12, pl. 3, figs 7-10.
Germain 1981, p. 32, pl. 7, figs 11-9, pl. 154, fig. 1.
John 1983, p. 21, pl. 5, figs 5-8.
Krammer & Lange-Bertalot 1991, p. 44, fig. 44: 1-10.
Thomas 1983, p. 25, pl. 2, figs 1, 2.
Vyverman et al. 1995, p. 32, pl. 2, fig. 1, pl. 16, fig. 4.
Common varieties: None
Similar species: Aulacoseira spp. (valve view) (pp. 23-25)
'Cyclostephanoid' group (pp 33-35)
Cyclotella pseudostelligera (p. 37)
Cyclotella stelligera (p. 38)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: widespread and abundant. Considered to be
facultative planktonic. Also a facultative heterotroph
including being a nitrogen heterotroph. Ecologically
tolerant.
Fig. 28. Cyclotella meneghiniana: (a) Loddon River, VIC, x1950; (b) River Torrens, SA, x2400; (c)
Dawesley Creek, SA, x2400; (d) girdle view, Dawesley Creek, SA, x2100.

37
Cyclotella pseudostelligera
Hustedt 1939 (Figs 29a-d)
Synonyms: None
Description: Cells disc or drum-shaped, with a circular valve face and shallow mantle. Valve face with
radially arranged areolae, extending inwards for almost 0.25-0.4 of the radius length. Areolae grouped into
fasicles, creating a ridge-like appearance around the margin of the valve face. Valve centre ± distinct stellate
pattern, slightly undulate. Valve margin with row of clear fultoportulae. Valve diameter 7.5-16 (4-10) µm,
fascicle density 14-18/10 µm.
Key references: Foged 1978, p. 45, pl. 2, fig. 5.
Krammer & Lange-Bertalot 1991, p. 51, fig. 49: 5-7
Vyverman et al. 1995, p. 31, pl. 16, fig. 1.
Common varieties: None
Similar species: Cyclotella stelligera (p. 38)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Not as widespread as C. stelligera. Planktonic,
but can also be deposited on the epilithon and
epilithon.
Fig. 29. Cyclotella pseudostelligera: (a) Tookayerta Creek, SA, x1400; (b) Murray River, NSW, x1400; (c)
Murray River, NSW, x1400; (d) C. pseudostelligera?, Meander River, TAS, x1400.

38
Cyclotella stelligera
Cleve & Grunow in Van Heurck 1882 (Figs 30a-b)
Synonyms: Cyclotella meneghiniana var. stelligera Cleve & Grunow in Cleve 1881
Cyclotella meneghiniana var. stellulifera Grunow in Cleve 1881
Cyclotella meneghiniana var. stellifera Grunow in Van Heurck 1882
Description: Cell disc or drum shaped, with a circular valve face and shallow mantle. In girdle view, cell
appearing rectangular. The valve face with a conspicuous marginal row of radially arranged areolae
extending inwards for almost 30% of the radius. Areolae grouped into fascicles, creating a ridge-like
appearance around the margin of the valve face. Central area of the valve highly complex, consisting of a
central pore surrounded by numerous (usually between 6-18) linear fascicles (dense rows of areolae)
arranged in a relatively unstructured stellate pattern. Central area difficult to distinguish in smaller
specimens. Valve diameter 5-13 (5-40) µm, marginal fascicles 8-11 (10-14)/10 µm.
Key references: Foged 1978, p. 45, pl. 2, fig. 11.
Germain 1981, p. 34, pl. 8, figs 14-18.
Hodgson et al. 1997, p. 45, pl. 1, figs 1, 2, 4, 7.
Holland & Clark 1989, p. 12, pl. 3, figs 11-13.
John 1983, p. 21, pl. 5, fig. 9.
Krammer & Lange-Bertalot 1991, p. 50, fig. 49: 1-4.
Thomas 1983, p. 26, pl. 2, fig. 3.
Vyverman et al. 1995, p. 32, pl. 16, figs 2, 3.
Common varieties: None
Similar species: Cyclotella meneghiniana (p. 36)
Cyclotella pseudostelligera (p. 37)
Cyclotella tasmanica Haworth & Tyler 1993 (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but rarely very abundant in stream
samples. Much more common in lacustrine
environments. Planktonic but also commonly deposited
in epipelic and epilithic habitats. C. stelligera closely
resembles another small Cyclotella species, C.
pseudostelligera. Superficially, there appears to be
very little difference between the two species when
viewed under LM. Krammer & Lange-Bertalot (1991)
separate the two species primarily on the basis of cell
size, C. pseudostelligera < 10µm, C. stelligera >
10µm, and the presence of marginal spines. Haworth &
Hurley (1984) have proposed that C. pseudostelligera
is a variety of C. stelligera.
Fig. 30. Cyclotella stelligera: (a) Deep Creek, VIC, x1550; (b) Wallpolla Creek, VIC, x1450; (c) Mt Emu Creek, VIC,
x1700.

39
Genus Cymbella sensu lato
Key to the common species
1a. Valve tending towards naviculoid/lanceolate rather than clearly dorsiventral ....................................... 2
1b. Valve clearly dorsiventral .................................................................................................................... 3
2a. Valve ends rostrate to capitate; central striae parallel to weakly radial, becoming more radial distally .....
................................................................................................................ Encyonopsis microcephala1
2b. Valve ends bluntly rounded (sometimes slightly drawn out); central striae strongly radial, becoming
parallel to convergent distally .............................................................................. Cymbella pusilla part
3a. Central area indistinct; valve £8 mm wide .......................................................... Cymbella pusilla part2
3b. Central area distinct, circular or circular-elliptical; valve ³12 mm wide ................................................ 4
4a. One or more stigmata associated with the central area .......................................................................... 5
4b. No stigmata associated with the central area .......................... Other species not included in this guide
5a. Raphe filiform with enlarged proximal ends; central area with one large, isolated stigma ........................
................................................................................................................................... Cymbella tumida
5b. Raphe with reverse-lateral proximal ends; one to five stigmata, typically associated with the ventral
striae .......................................................................................................................... Cymbella cistula
1Several other naviculoid Cymbella sensu lato with rostrate to capitate ends are described and illustrated in Krammer
and Lange Bertalot (1986); however, these are generally larger and/or more coarsely striated than E. microcephala (p
**).
2May be confused with taxa of the genus Encyonema

40
Cymbella cistula
(Ehrenberg) Kirchner 1878 (Figs 31a-b)
Synonyms: Bacillaria cistula Ehrenberg 1828
Cymbella maculata (Kützing) Kützing 1844
Description: Valve dorsiventral, dorsal margin strongly convex, ventral margin variable between straight,
weakly convex or concave. Valve with bluntly rounded ends. Axial area located centrally, narrow, linear,
and dorsally arched. Raphe with reverse-lateral proximal ends (see fig. ) and "scythe-shaped" distal ends.
Central area large and circular. One to five isolated stigmata prominent on the ventral side of the central
nodule, associated with the ventral striae. Transapical striae more or less radial throughout the valve. Striae
appearing coarsely punctate/lineolate. Length 38-70 (35-120) µm, width 10-18 (13-25) µm, striae density 10-
12 (7-14)/10 µm, punctae density 20-24 (18-21)/10 µm.
Key references: Foged 1978, p. 46, pl. 38, fig. 11.
Germain 1981, p. 282, pl. 103, figs 1-11.
Hodgson et al. 1997, p. 48.
Krammer & Lange-Bertalot 1986, p. 316, figs 127: 8-11, 128: 1-6.
Patrick & Reimer 1975, p. 62, pl. 11, figs 3-4.
Vyverman et al. 1995, p. 34, pl. 11, figs 9, 10, pl. 12, figs 1-3, 5, 7, pl. 32, 1-5, 11-19.
Common varieties: None
Similar species: Cymbella tumida (p. 41)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but rarely abundant. Found in
epipelic and epilithic assemblages and commonly
associated with epiphytic communities. Occurs in
waters with a broad range of nutrient concentrations.
Fig. 31. (a) Cymbella cistula, Glenelg River, VIC,
x1100; (b) Cymbella cf cistula, Deep Creek, VIC,
x1100.

41
Cymbella tumida
(Brébisson ex Kützing) Grunow in Van Heurck 1880 (Figs 32)
Synonyms: Cocconema tumidum Brébisson ex Kützing 1849
Cymbella stomatophora Grunow in A. Schmidt 1875
Description: Valve dorsiventral, with a straight to slightly convex ventral margin, sometimes swollen
(tumid) in the centre. Ends broadly rounded, sometimes with dorsal indentations. Axial area narrow,
centrally located and strongly arched dorsally. Central area circular-elliptical, with a large, single stigma
present on the ventral side. Stigma entering valve obliquely towards the central nodule. Raphe filiform,
proximal ends enlarged, deflected ventrally, distal ends 'sickle-shaped', dorsally deflected. Striae radiate,
coarsely punctate, denser at valve ends. Length 37-70 (35-120) µm, width 16-18 (12-25) µm, striae 9-10 (8-
13)/10 µm, punctae 18-20 (16-20)/10 µm,
Key references: Foged 1978, p. 49, pl. 37, figs 1-3.
Germain 1981, p. 288, pl. 106, figs 1, 2.
Holland & Clark 1989, p. 13, pl. 4, figs 5-7.
Krammer & Lange-Bertalot 1986, p. 318, fig. 130; 4-6.
Patrick & Reimer 1966, p. 58, pl. 10, fig. 8.
Common varieties: None
Similar species: Cymbella cistula (p. 40)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but rarely abundant. Most
commonly found in epipelic and epilithic
assemblages. Easily distinguished by the single,
prominent stigma which forms a tube directed toward
the central nodule.
Fig. 32. Cymbella tumida, Ovens River, VIC, x2000.

42
Encyonopsis microcephala
(Grunow in Van Heurck) Krammer 1997 (Figs 33a-b)
Synonyms: Cymbella ruttnerii Hustedt 1931
Navicula incompta Krasske 1932
Cymbella microcephala Grunow in Van Heurck 1880
Description: Valve appearing slightly dorsiventral to lanceolate, dorsal margin convex, ventral margin
almost straight to slightly convex. Valve ends drawn out, rostrate to capitate. Axial area narrow, more or less
centrally positioned. Raphe filiform, straight, slightly eccentric, and somewhat arched so that the proximal
ends are weakly, dorsally deflected. Proximal raphe ends close together. Central area absent. Transapical
striae parallel to weakly radial in the centre, increasingly radial towards the valve ends. Striae finely
lineolate, but not usually distinguishable under LM. Length 10-18 (10-30) µm, width 3-4 (2.4-4) µm, striae
density 22-24 (22-30)/10 µm.
Key references: Foged 1978, p. 48.
Germain 1981, p. 274, pl. 99, figs 27-30.
Hodgson et al. 1997, p. 51.
Krammer & Lange-Bertalot 1986,p. 327, fig. 134: 23-32.
Patrick & Reimer 1975, p. 33, pl. 4, figs 12a-13b.
Vyverman et al. 1995, p. 38.
Common varieties: None
Similar species: Achnanthidium minutissimum (girdle view) (p. 10)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be moderately abundant.
Found on the epipelon and epilithon and commonly
associated with epiphytic communities. May be
confused with small Navicula spp. as it is only weakly
dorsiventral.
Fig. 33. Encyonopsis microcephala: (a) Deep Creek, VIC, x2500; (b) Kent River, WA, x2000.

43
Navicella pusilla
(Grunow ex A. Schmidt) Krammer 1997 (Figs 34a-c)
Synonyms: Cymbella pusilla Grunow ex A. Schmidt 1875
Description: Valve narrow with moderately convex dorsal margin and weakly concave to almost straight
ventral margin (tending to naviculoid), Ends bluntly rounded, sometimes very slightly drawn out. Axial area
narrow, raphe straight with large semi-circular terminal fissures. Central area transapically widened. Medial
striae strongly radial, alternately longer and shorter. Striae parallel to convergent distally. Length 21-28 (18-
42) µm, width 5-6 (4-8) µm, striae 15-18 (15-20)/10 µm.
Key references: Foged 1978, p. 48.
Germain 1981, p. 286, pl. 105, fig. 6.
Krammer & Lange-Bertalot 1986, p. 340, fig. 148: 1-9.
Patrick & Reimer 1975, p. 25, pl. 3, fig. 18.
Common varieties: None
Similar species: Encyonema gracile (p. 45)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be very abundant. Usually
confined to brackish to saline environments. Found in
epipelic and epilithic assemblages and commonly
associated with epiphytic communities.
Fig. 34. Navicella pusilla: (a) Mount Barker Creek, SA, x1730; (b) Wannon River, VIC, x1650; (c) Salt
Creek, SA, x1750.

44
Diatoma tenuis
Agardh 1812 (Fig. 35a)
Synonyms: Refer to variety descriptions below.
Description: Valve linear, occasionally linear-lanceolate, with bluntly rounded, subcapitate ends. Axial area
indistinct, formed by a narrow, central sternum. Valve with conspicuous internal transverse costae, 8-10 (6-
10)/10 µm. Striae parallel and closely spaced, therefore usually not seen under LM. Length 24-63 (22-120)
µm, width 2-3 (2-5) µm.
Key references: Foged 1978, p. 51.
Hodgson et al. 1997, p. 56.
Krammer & Lange-Bertalot 1991, p. 97, figs 96: 1-10.
Patrick & Reimer 1966, p. 108, pl. 2, fig. 5.
Vyverman et al. 1995, p. 42.
Common varieties:
var. tenuis
Syn: Diatoma tenuis var. elongatum Lyngbye 1819
Diatoma elongatum (Lyngbye) Agardh 1824
Diatoma mesoleptum Kützing 1844
Nominate variety, description as above.
var. elongatum Lyngbye 1819
Syn: Diatoma elongatum (Lyngbye) Agardh 1824
Valve linear with capitate ends (Patrick & Reimer, 1966).
Similar species: Diatoma moniliformis Kützing 1833 (Fig. 35b) (Not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and occasionally abundant,
particularly in waters with elevated EC. Found in both
epipelic and epilithic assemblages.
Fig. 35. (a) Diatoma tenius, Wimmera River, VIC, x1750; (b) Diatoma cf. moniliformis, Jacksons Creek,
VIC, x2000.

45
Genus Encyonema
Key to the common species
1a. Dorsal margin strongly convex; length:width ratio £5 ......................................................................... 2
1b. Dorsal margin weakly convex; length:width ratio ³5 ............................................. Encyonema gracile
2a. Striae finely punctate, punctae generally clearly visible under the light microscope, £30 punctae/10 mm
........................................................................................................................ Encyonema silesiacum1
2b. Striae finely lineolate, lineolae generally indistinct under the light microscope, ³30 lineolae/10 mm .......
............................................................................................................................ Encyonema minutum
Encyonema gracile
Rabenhorst 1853 (Figs 36a-b)
Synonyms: Cocconema gracile Ehrenberg 1843
Cymbella scotica W. Smith 1853
Cymbella gracilis (Ehrenberg) Kützing 1844
Cymbella lunata W. Smith 1855
Description: Valve narrowly dorsiventral, dorsal margin weakly convex, ventral margin straight, sometimes
slightly convex in the centre. Valve ends acutely rounded, occasionally slightly bent ventrally. Axial area
narrow and slightly eccentric ventrally. Raphe filiform, proximal ends deflected dorsally, distal ends
deflected ventrally. Axial area small, slightly transverse. Transapical striae parallel to slightly radial, ventral
striae convergent distally. Striae finely punctate. Punctae not usually seen under LM. Length 25-43 (22-57)
µm, width 4.5-7 (4.5-9) µm, striae density 11 -14 (9-18)/10 µm.
Key references: Foged 1978, p. 47, pl. 37, figs. 11, 12.
Germain 1981, p. 292, pl. 107, figs 6-10.
Hodgson et al. 1997, p. 50, pl. 6, fig. 16.
Krammer & Lange-Bertalot 1986, p. 308, fig. 120: 1-16.
Patrick & Reimer 1975, p. 46, pl. 7, figs 11-14.
Vyverman et al. 1995, p. 37, pl. 31, figs 4, 5.
Common varieties: None
Similar species: Encyonema minutum (p. 46)
Encyonema silesiacum (p. 47)
Navicella pusilla (p. 43)
1Large and coarse forms may be confused with E. mesiana (not included in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread, particularly in upland areas, but
rarely abundant. Relatively narrow ecological
tolerances. Mostly found in epilithic assemblages.

46
Encyonema gracile cont.
Fig. 36. Encyonema gracile: (a) Crystal Brook, VIC, x1600; (b) Western Creek, TAS, x1600.
Encyonema minutum
(Hilse ex Rabenhorst) Mann 1990 (Figs 37a-b )
Synonyms: Cymbella minuta Hilse ex Rabenhorst 1862
Cymbella ventricosa Kützing 1844
Description: Valve dorsiventral, crescent-shaped, dorsal margin strongly convex, ventral margin generally
straight, sometimes slightly convex. Ends acutely rounded to capitate, often ventrally bent. Axial area
narrow, distinctly ventral, running almost parallel to the ventral margin. Central area absent. Raphe filiform,
proximal ends deflected dorsally, distal ends deflected ventrally. Striae finely lineolate (lineolae usually not
visible under LM), slightly radial to parallel, more densely arranged towards the ends. Length 18-20 (7-32)
µm, width 6 (3.9-7) µm, striae 10-12 (10.5-20)/10 µm, lineolae 30 (30-38)/10 µm.
Key references: Foged 1978, p. 50, pl. 37, figs 6,8.
John 1983, p. 145, pl. LX, figs 8,9.
Holland & Clark 1989, p. 12, pl. 4, fig. 4.
Krammer 1982, p. 22, pl. 1026-1030.
Krammer & Lange-Bertalot 1986, p. 305, figs 119: 1-13, 16: 4.
Patrick & Reimer 1975, p. 47, pl. 8, figs 1a-4b.
Thomas 1983, p. 28, pl. 5, fig. 12.
Common varieties: None
Similar species: Encyonema silesiacum (p. 47)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and moderately abundant.
Wide ecological tolerances. Found in both
epilithic and epipelic assemblages
Fig. 37. Encyonema minutum: (a) Adelong River,
NSW, x1900; (b) Ovens River, VIC, x2250.

47
Encyonema silesiacum
(Bleisch in Rabenhorst) Mann 1990 (Figs 34a-d)
Synonyms: Cymbella ventricosa Kützing 1844 pro parte
Cymbella minuta var. silesiaca (Bleisch) Reimer 1975
Description: Valve dorsiventral, crescent-shaped, dorsal margin strongly convex, ventral margin generally
straight, sometimes slightly convex in the centre. Valve ends acutely rounded to almost subcapitate, often
ventrally bent. Axial area narrow, widening towards the centre, distinctly ventral, and running almost parallel to
the ventral margin. Raphe filiform, straight, proximal ends dorsally deflected, distal ends ventrally deflected.
Central area absent. An isolated stigma is often present at the end of the central dorsal stria. Dorsal striae parallel
to weakly radial in the centre becoming increasingly radial distally. Ventral striae parallel to weakly radial in the
centre becoming convergent distally. Striae finely punctate (should be visible under LM). Length 23-32 (15-46)
µm, width 6.5-7.5 (6.5-14.2) µm, striae density 11 (10.5-20)/10 µm,punctae density (24-30)/10 µm.
Key references: Krammer 1982, p. 24, pl. 1032-1034.
Krammer & Lange-Bertalot 1986, p. 304, fig. 117: 1-24.
Patrick & Reimer 1975, p. 49, pl.8, figs 7a-10b.
Common varieties: None
Similar species: Encyonema gracile (p. 45)
Encyonema minutum (p. 46)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and moderately abundant.
Found in both epilithic and the epipelic
assemblages. There is some doubt about the status
of E. silesiacum and E. minutum as they ma y be
morphotypes of the same species.
Fig. 38. Encyonema silesiacum: (a) East Tanjil River, VIC, x1700; (b) Ovens River, VIC, x1400; (c-d)
Encyonema cf. silesiacum; (c) Donnely River, WA, x1700; (d) Bendigo Creek, VIC, x1200.

48
Genus Entomoneis
Key to the common species
1a. Keel with distinct reinforced ribs ............................................................................ Entomoneis costata
1b. Ribs absent .......................................................................................................................................... 2
2a. Ver y delicate and weakly silicified ..................................................................... Entomoneis paludosa
2b. Coarse structure; striae clearly evident ....................................................................... Entomoneis alata
Entomoneis alata
(Ehrenberg) Ehrenberg 1845 (Fig. 39)
Synonyms: Navicula alata Ehrenberg 1840
Amphiprora alata (Ehrenberg) Kützing 1844
Description: In valve view, linear-elliptical to linear-lanceolate with acutely rounded ends. In girdle view,
panduriform, with numerous intercalary bands. Valve strongly silicified, with a prominent, narrow, upright, S-
shaped keel that is constricted in the central area. The raphe canal runs along the apex of the keel and is
generally difficult to distinguish under LM. Striae on the keel distinctly punctate. Separation lines (longitudinal
lines on either side of the keel where it joins the valve face) smoothly curved to wea kly undulate and also
distinctly but irregularly punctate. Transapical striae on the valve surface relatively coarse and finely lineolate.
Length 54 (55-160) µm, width 25 (30-60) µm, striae density (valve body) 23 (15-17)/10 µm.
Key references: Foged 1978, p. 31, pl. 35, fig. 1.
Germain 1981, p. 136, pl. 50, figs 3-5.
Krammer & Lange-Bertalot 1986, p. 438, fig. 203: 1-4.
Patrick & Reimer 1975, p. 3, pl. 1, fig. 2.
Common varieties: None
Similar species: Entomoneis costata (p. 49)
Entomoneis paludosa (p. 50)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 39. Entomoneis alata, Mount Barker Creek,
SA, x1650.
Notes: Widespread but confined to brackish and saline
water s. Most common in waters of high nutrient
concentrations. Mostly found in epipelic assemblages but
can also be planktonic.

49
Entomoneis costata
(Hustedt) Reimer 1975 (Fig. 40)
Synonyms: Amphiprora costata Hustedt 1930
Amphiprora hustedtii Cholnoky 1960
Description: Linear-lanceolate in valve view with acutely rounded ends. Panduriform in girdle view, with
numerous, indistinct intercalary bands. Valve delicately silicified, with a prominent, narrow, upright S-
shaped keel that is constricted in the central area. The raphe canal runs along the apex of the keel and is
generally difficult to distinguish under LM. Valve surface and keel with coarse, reinforced ribs, that are
distinctly more robust on the keel. Separation lines (longitudinal lines on either side of the keel where it joins
the valve face) strongly wavy. Striae on the valve surface and keel relatively fine. Length 32 (35-48) µm,
width 17 (18-24) µm, rib density 9 (7)/10 µm, striae density (24)/10 µm.
Key references: Foged 1978, p. 31, pl. 35, fig. 5.
Germain 1981, p. 136, pl. 50, fig. 6.
Krammer & Lange-Bertalot 1986, p. 439, figs 203: 5, 204: 1.
Common varieties: None
Similar species: Entomoneis alata (p. 48)
Entomoneis paludosa (p. 50)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but not usually abundant.
Narrow EC tolerance. Most commonly found in
epipelic assemblages but can also be planktonic.
Fig. 40. Entomoneis costata, Perup River, WA, x1750.

50
Entomoneis paludosa
(W. Smith) Reimer 1975 (Figs 41)
Synonyms: Amphiprora paludosa W. Smith 1853
Description: Linear-lanceolate in valve view with acute, rounded ends. Panduriform in girdle view, with
numerous indistinct intercalary bands. Valve delicately silicified with a prominent, narrow, upright S-shaped
keel that is constricted in the central area. The raphe canal runs along the apex of the keel and is generally
difficult to distinguish under LM. Separation lines (longitudinal lines on either side of the keel where it joins
the valve face) usually weakly undulate, sometimes with a bulge near the centre of each wing. Longitudinal
lines not punctate. Transapical striae on the valve and keel surfaces finely punctate (punctae not usually
visible under LM). Length 24 (40-130) µm, width 13 (20-50) µm, striae density (valve body) (19-23)/10 µm.
Key references: Foged 1978, p. 31, pl. 35, fig. 2.
Krammer & Lange-Bertalot 1986, p. 439, figs 204: 2-4, 205: 9.
Patrick & Reimer 1975, p. 4, pl. 1, fig. 1.
Common varieties: None
Similar species: Entomoneis alata (p. 48)
Entomoneis costata (p. 49)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread in brackish and saline
environments. Will tolerate hypersaline waters
also. Mostly recorded in epipelic assemblages but
can also be planktonic.
Fig. 41. Entomoneis paludosa, Marne River, SA, x2050.

51
Genus Epithemia
Key to the common species
1a. Dorsal margin more strongly arched than the ventral margin; ends subcapitate to capitate; raphe canal
positioned along the ventral margin distally but rising sharply toward the dorsal margin at the centre .....
.................................................................................................................................... Epithemia sorex
1b. Valves appearing otherwise ................................................................................................................. 2
2a. Dorsal and ventral margins more or less equally arched; ends broad rostrate to subcapitate; raphe canal
positioned along the ventral margin, barely rising dorsally at the centre .................... Epithemia adnata
2b. Valves appearing otherwise ................................................... Other species not included in this guide
Epithemia adnata
(Kützing) Rabenhorst 1853 (Figs 42a-c)
Synonyms: Refer to individual variety descriptions.
Description: Valve arcuate, dorsiventral, with convex dorsal margin and concave ventral margin. Valve
ends broadly subcapitate. Raphe canal adjacent to the ventral margin, curved towards the dorsal margin at
the valve centre (but barely reaching middle of valve), forming a distinct "V-shape". Central nodule located
almost halfway between the dorsal and ventral margins. Valve surface ornamented with transverse costae
that are marginally radial and contain three to five rows of areolae between each pair. Length 31-50 (15-150)
µm, width 10-10.5 (7-14) µm, striae density 10-13 (12-13)/10 µm.
Key references: John 1983, p. 159, pl. 67, fig. 2.
Krammer & Lange-Bertalot 1988, p. 152, figs 107: 1-11, 108: 1-3.
Patrick & Reimer 1975, p. 179, pl. 24, figs 3-9.
Thomas 1983, p. 30, pl. 11, fig. 2.
Common varieties:
var. adnata
Syn: Frustulia adnata Kützing 1833
Navicula zebra Ehrenberg 1835
Epithemia zebra (Ehrenberg) Kützing 1844
Cystopleura zebra (Ehrenberg) Kuntze 1891
Nominate variety, description as above.
var. minor (Peragallo & Héribaud) Patrick 1975
Syn: Epithemia zebra var. minor Peragallo & Héribaud 1893
Length to width ratio much less than other varieties (3:7-4:1) (Patrick & Reimer, 1975).
var. porcellus (Kützing) Patrick 1975
Syn: Epithemia porcellus Kützing 1844
Epithemia zebra var. porcellus (Kützing) Grunow 1862
Cystopleura zebra var. porcellus (Kützing) De Toni 1892
Valve ends narrow, truncate to slightly capitate (Patrick & Reimer, 1975). Length to width ratio higher
than other varieties.

52
Epithemia adnata cont.
var. probiscidea (Kützing) Patrick 1975
Syn: Epithemia proboscidea Kützing 1844
Epithemia zebra var. proboscidea (Kützing) Grunow 1862
Cystopleura zebra var. proboscidea (Kützing) De Toni 1892
Valve ends rostrate, sometimes a little capitate, more distantly spaced costae (Patrick & Reimer, 1975).
var. saxonica (Kützing) Patrick 1975
Syn: Epithemia saxonica Kützing 1844
Epithemia zebra var. saxonica (Kützing) Grunow 1862
Cystopleura zebra var. saxonica (Kützing) De Toni 1892
Ventral margin is more concave. Valve generally smaller than nominate variety (Patrick & Reimer,
1975).
Similar species: Epithemia sorex (p. 53)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread, particularly in alkaline
waters, and moderately abundant. Found in
epipelic and epilithic assemblages but also
associated with epiphytic habitats. Very common
in lowland rivers.
Fig. 42. Epithemia adnata: (a-b) Surrey River, VIC, x1800; (c) Deep Creek, VIC, x1500.

53
Epithemia sorex
Kützing 1844 (Figs 43a-b)
Synonyms: Cystopleura sorex (Kützing) Kuntze 1891
Description: Valve markedly dorsiventral with a strongly convex dorsal margin and concave ventral
margins. Valve ends drawn out, broadly rostrate to subcapitate. The raphe canal closely follows the ventral
margin distally and curves sharply towards the dorsal margin to form a distinctive "V-shape" in the centre of
the valve (almost reaching dorsal margin). Valve surface ornamented with transverse costae that are radial
with between two to three rows of areolae between each pair. Length 31-33 (8-70) µm, width 8-10 (6.5-16)
µm, striae density 12-13 (10 -15)/10 µm, areolae density 12 15)/10 µm.
Key references: Germain 1981, p. 318, pl. 118, figs 5, 6.
Holland & Clark 1989, p. 14, pl. 6, fig. 17.
John 1983, p. 161, pl. 67, figs 7, 8.
Krammer & Lange-Bertalot 1988, p. 154, figs 106: 1-11, 108: 1-3.
Patrick & Reimer 1975, p. 188, pl. 27, figs 4.
Common varieties: None
Similar species: Epithema adnata (p. 52)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and generally more abundant
than E. adnata. Preference for alkaline waters.
Found in epipelic and epilithic assemblages but
also associated with epiphytic habitats. Very
common in lowland rivers.
Fig. 43. Epithemia sorex: (a-b) Surrey River, VIC, x1800.

54
Genus Eunotia
Key to the common species
1a. Valves with prominent undulations on both margins giving a ‘serpent-like’ profile .Eunotia serpentina
1b. Valves appearing otherwise ................................................................................................................. 2
2a. Ventral margin a single curve; valve distinctly arcuate, ends not drawn or flexed ....... Eunotia bilunaris
2b. Valves appearing otherwise ................................................................................................................. 3
3a. Ventral margin straight to slightly curved; ends slightly drawn or flexed ........................ Eunotia minor
3b. Valves appearing otherwise ................................................... Other species not included in this guide
Eunotia bilunaris
(Ehrenberg) Mills 1934 (Figs 44a-c)
Synonyms: Refer to individual variety descriptions.
Description: Valve slender, lunate/arcuate, with a strongly concave ventral margin and with the dorsal
margin parallel to the ventral margin. Valve ends broadly rounded, occasionally somewhat swollen or with a
slight dorsal indentation. Vestigial raphe short, extending well onto the valve face, curving back towards the
centre. Striae parallel. Length 28-62 (10-205) µm, width 2.5-4 (1.9-6) µm, striae density16-19 (9-28)/10 µm.
Key references: Germain 1981, p. 94, pl. 32, figs 7-10..
Holland & Clark 1989, p. 15, pl. 8, fig. 4.
Krammer & Lange-Bertalot 1991, p. 179, figs 137, 138: 10-24.
Patrick & Reimer 1966, p. 189, pl. 10, figs 4, 5.
Thomas 1983, p. 35, pl. 3, fig. 4.
Common varieties:
var. bilunaris
Syn: Synedra bilunaris Ehrenberg 1832
Synedra lunaris Ehrenberg 1832
Exilaria curvata Kützing 1834
Ceratoneis lunaris (Ehrenberg) Grunow in Rabenhorst 1865
Eunotia lunaris (Ehrenberg) Grunow in Van Heurck 1881
Nominate variety, description as above.
var. linearis (Okuno) Lange-Bertalot & Norpel 1991
Syn: Eunotia flexuosa var. linearis Okuno 1952
Eunotia okavangoi Cholnoky 1966
Eunotia curvata var. linearis (Okuno) Kobayasi, Ando & Nagumo 1981
Valve less arcuate, generally longer, and more strongly silicified (Krammer & Lange-Bertalot, 1991).
var. mucophila Lange-Bertalot & Norpel 1991
Syn: Synedra lunaris var. subarctica Nägeli ex Kützing 1849
Eunotia lunaris var. subarcuata (Nägeli) Grunow in Van Heurck 1881
Eunotia subarcuata (Nägeli) Pantosek 1902
Valve width less than other varieties (1.9-2.7µm), striae slightly more dense (20-28/10µm) (Krammer
& Lange-Bertalot, 1991).

55
Eunotia bilunaris cont.
Similar species: Eunotia naegelii (fig. 44d) Migula in Thomé 1907 (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Frequently found in upland streams but
rarely abundant. Will inhabit both epipelic and
epilithic habitats.
Fig. 44. Eunotia bilunaris: (a) Carey Brook, WA, x1600; (b) Running Jump Creek, VIC, x1700; (c) Carey
Brook, WA, x1450; (d) Eunotia naegelii, Margaret River, WA, x1750.

56
Eunotia exigua
(Brébisson ex Kützing) Rabenhorst 1864 (Figs 45a-c)
Synonyms: Refer to individual variety descriptions.
Description: Valve dorsiventral, with strongly convex dorsal margin and straight to concave ventral margin.
Dorsal margin sometimes with slight undulations. Dorsal margin strongly constricted distally, forming
broadly capitate ends. Vestigial raphe ends often visible towards the ends on the ventral margin. Striae
parallel. Length 11.5-15 (8-28) µm., width 3-3.5 (2.5-4) µm., striae density 20-24 (18-24)/10µm.
Key references: Foged 1978, p. 57.
Hodgson et al. 1997, p. 62.
John 1983, p. 66, pl. 28, fig. 8.
Krammer & Lange-Bertalot 1991, p. 199, fig. 153: 5-43.
Vyverman et al. 1995, p. 46, pl. 18, figs 24, 26, 27.
Common varieties:
var. exigua
Syn: Himantidium exiguim Brébisson ex Kützing 1849
Nominate variety, refer to description above.
var. undulata Magdeburg 1926
Syn: Eunotia exigua var. bidens Hustedt 1930
Dorsal margin with two undulations (Krammer & Lange-Bertalot, 1991).
var. tridentula Oestrup 1910
Dorsal margin with three undulations (Krammer & Lange-Bertalot, 1991).
Similar species: Eunotia paludosa Grunow 1862 (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Largely confined to upland streams.
Mostly recorded in epipelic and epilithic
assemblages. Predominantly a freshwater species.
Fig. 45. Eunotia exigua: (a-c) East Tanjil River, VIC, x1700.

57
Eunotia minor
(Kützing) Van Heurck 1881 (Figs 46a-b)
Synonyms: Himantidium minus Kützing 1844
Eunotia pectinalis var. minor (Kützing) Rabenhorst 1864
Eunotia impressa var. angusta Grunow in Van Heurck 1881
Description: Valve weakly lunate, with a straight to slightly concave ventral margin, and a convex dorsal
margin. Valve slightly indented on the dorsal margin towards the ends. Apices broadly rounded. Vestigial
raphe ends just visible distally on the ventral margin. Striae parallel in the central region becoming weakly
radial towards the valve ends. Length 32 (20-60) µm, width 5.5 (4.5-8) µm, striae density 10 (9-15)/10 µm.
Key references: Krammer & Lange-Bertalot 1991, p. 196, fig. 142: 7-15.
Common varieties: None
Similar species: Eunotia bilunaris (p. 54)
Eunotia circumborealis Lange-Bertalot & Nörpel 1991 (Not described in this guide)
Eunotia implicata Nörpel, Lange-Bertalot & Alles 1991 (Not described in this guide)
(Not described in this guide)
Eunotia intermedia (Krasske ex Hustedt) Nörpel & Lange-Bertalot 1991
Eunotia soleirolii (Kützing) Rabenhorst 1864 (Not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Frequently found in upland streams but
rarely abundant. Similar ecological tolerances to
E. bilunaris. Will inhabit both epipelic and
epilithic assemblages. Eunotia minor is very
similar to E. implicata where the dorsal margin is
depressed and two humps are formed.
Fig. 46. Eunotia minor: (a) Pollard Brook, WA, x 1700; (b) Hope Creek, VIC, x1750.

58
Eunotia serpentina
Ehrenberg 1854 (Figs 47)
Synonyms: Amphicampa mirabilis Ehrenberg ex Ralfs 1861
Eunotia eruca Hustedt 1913
Description: Valve with weakly convex dorsal margin, weakly concave ventral margins, and broadly
rounded valve ends. Each margin with three to six prominent undulations, giving the valve a 'serpent-like'
profile. Axial area (pseudoraphe) extremely narrow and linear, located near the ventral margin. Striae
parallel to weakly radial throughout the valve. Striae distinctly punctate. A prominent terminal pore is
usually present on one of the valves. Length 57-120 µm, width 9-15 µm, striae density 9 -10/10 µm.
Key references: Foged 1978, p. 60, pl. 10, figs 3-6.
Holland & Clark 1989, p. 15, pl. 7, figs 1-6.
John 1983, p. 44, pl. 17, figs 2, 3.
Common varieties: None
Similar species: None
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widely distributed but rarely abundant.
Found in both epipelic and epilithic assemblages.
Fig. 47. Eunotia serpentina, Sevens Creeks, VIC, x1200.

59
Genus Fallacia
Key to the common species
1a. Central area and adjoining lateral areas forming distinctive ‘H-shape’ ...................... Fallacia pygmaea
1b. Central area not distinctive, axial area with single longitudinal row of coarse punctae to one side ...........
...................................................................................................................................... Fallacia tenera
Fallacia pygmaea
(Kützing) Stickle & Mann 1990 (Figs 48a-c)
Synonyms: Navicula pygmaea Kützing 1849
Navicula minutula W. Smith 1853
Diploneis hudsonis (Grunow) Cleve 1894
Description: Valve elliptical to linear-elliptical with broadly rounded ends. Axial area of variable width,
flanked on either side by short striae that in places may consist only of a single punctum. Raphe filiform,
straight to slightly arcuate. The proximal raphe ends deflected to the same side. Central area broadly
rectangular, extending laterally between the marginal striae and those adjacent to the axial area, converging
at the valve ends and thus forming a distinctive "H" shape. Marginal striae ± more widely spaced in the
centre, continuously radial and finely punctate. Length 18-28 (10-62) µm, width 7-9 (6-24) µm, striae
density 25-28 (22-28)/10 µm.
Key references: Germain 1981, p. 218, pl. 82, figs 3, 4.
Holland & Clark 1989, p. 21, pl. 16, figs 2, 3.
John 1983, p. 97, pl. 41, fig. 6.
Krammer & Lange-Bertalot 1986, p. 171, fig. 65: 1-6.
Common varieties: None
Similar species: Fallacia tenera (p. 60)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 48. Fallacia pygmaea: (a) Hindmarsh River,
SA, 1700x; (b) River Torrens, SA, 1700x; (c)
Pollard Brook, WA, 1700x.
Notes: Widespread but not abundant. More
common in lowland areas in waters with high
nutrient concentrations. Mostly found in epipelic
assemblages.

60
Fallacia tenera
(Hustedt) Mann 1990 (Figs 49a-e)
Synonyms: Navicula uniseriata Hustedt in A. Schmidt 1934
Navicula dissipata Hustedt in A. Schmidt 1936
Navicula tenera Hustedt 1937
Navicula auriculata Hustedt 1944
Navicula biseriata Brockmann 1952
Navicula insociabilis var. dissipatoides Hustedt 1957
Description: Valve elliptical to linear-elliptical with broadly rounded ends. Axial area narrow, raphe
filiform and distinctly arcuate. Proximal raphe ends may therefore appear deflected to one side. Central area
broad and rectangular. A single longitudinal row of punctae is present on one side of the axial area. Axial
area (including the longitudinal row of punctae) separated from the striae by a hyaline region which is
connected to the central area, thus forming a distinctive 'H' pattern. Marginal striae consisting of only two
punctae separated by a longitudinal line. The outer punctae are distinctly larger than the inner. Striae parallel
in the central region, tending to radial at the ends. Length 10-17 (9-27) µm, width 5-7 (4-9) µm, striae
density 14-20 (13-22)/10 µm.
Key references: John 1983, p. 102, pl. XLIII, fig. 1.
Krammer & Lange-Bertalot 1986, p. 175, figs 66: 19-23, 83: 5.
Patrick & Reimer 1966, p. 441, pl. 39, fig. 2.
Common varieties: None
Similar species: Fallacia pygmaea (p. 59)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but not abundant. More
common in lowland areas. Mostly found in
epipelic assemblages. Fallacia tenera is generally
easily distinguished by the single longitudinal row
of punctae on one side of the axial area. This
feature does vary considerably, and some
specimens may be found with complete or
incomplete longitudinal rows of punctae on both
sides of the axial area.
Fig. 49. Fallacia tenera: (a) Airport Drain, WA, x1700; (b) Wannon River, VIC, x1700, (c) Mount Barker
Creek, SA, x1700; (d) Kororoit Creek, VIC, x1700; (e) Hopkins River, VIC, x1800.

61
Genus Fragilaria sensu Gell et al. 1999 and related genera
Key to the common species
1a. With central area .................................................................................................................................2
1b Without central area .................................................................................... Fragilariaforma virescens
2a. Valves < 50 µm long ............................................................................................. Fragilaria capucina
2b. Valves > 50 µm long .................................................... Fragilaria nanana (not included in this guide)
Note: Many species that were previously found in the Fragilaria group are now found within the genera
Staurosira, Staurophora, Staurosirella, and Pseudostaurosira.
Fragilaria capucina
Desmazières 1925 (Figs 58a-i)
Synonyms: Refer to individual variety descriptions above.
Description: Valve extremely variable in shape and size, linear, linear-lanceolate to almost lanceolate, with
drawn out, sharpely or bluntly rounded, subcapitate to capitate ends. Some valves also with constriction in
the middle. Axial area (pseudoraphe) generally narrow and linear. Central area highly variable, from one-
sided and round, to transverse, reaching both margins, and circular to rectangular in shape. Transapical striae
parallel, density extremely variable. [Morphometrics: see variety descriptions below]
Key references: Foged 1978, p. 64, pl. 8, fig. 5.
Germain 1981, p. 64, pl. 19, figs 1-19.
Holland & Clark 1989, p. 15, pl. 8, figs 11, 12.
John 1983, p. 44, pl. 16, figs 12-14.
Krammer & Lange-Bertalot 1991, p. 121, figs 108: 1-21, 109: 1-29, 110: 1-22, 111: 1-3.
Patrick & Reimer 1966, p. 118, pl. 3, figs 5, 6, 14-16.
Common varieties:
var. capucina
Syn: Fragilaria capucina var. lanceolata Grunow in Van Heurck 1881
Synedra rumpens var. familiaris f. major Grunow in Van Heurck 1881
Valve generally lanceolate to linear, central area usually rectangular to circular. Length 27-42 µm, width
2-5 (3.5-4.5) µm, striae density 12-18 (12-17)/10 µm.
var. gracilis (Ostrup) Hustedt 1950
Syn: Synedra rumpens var. familiaris (Kützing) Grunow 1881
Fragilaria gracilis Oestrup 1910
Synedra familiaris Kützing 1844
Synedra famelica Kützing 1844
Valve narrowly elongate, linear, central area ± distinct. Length 29 µm, width 2-3 (2 -3) µm, striae
density 15-20 (20) /10 µm.
var. mesolepta (Rabenhorst) Rabenhorst 1864
Syn: Fragilaria mesolepta Rabenhorst 1861
Fragilaria subconstricta Oestrup 1910
Fragilaria tenuistriata Oestrup 1910
Valve large, broadly linear, centrally constricted and with subcapitate to subrostrate ends. Axial area
notably broad.

62
Fragilaria capucina cont.
var. distans Grunow in Van Heurck 1881
Syn: Synedra vaucheriae var. distans Grunow in Van Heurck 1881
Valve linear-lanceolate, drawn out, tapered capitate ends, central area one-sided, striae density
relatively coarse. Striae density 10/10 µm.
var. rumpens (Kützing) Lange-Bertalot 1991
Syn: Synedra rumpens Kützing 1844
Fragilaria pseudolaevissima Van Landingham 1971
Valve narrowly elongate, more or less lanceolate, centrally constricted and with tapered capitate ends.
Central area dilated, circular. Length µm, width 2-3(4 ) µm, striae density (18 -20) /10 µm.
var. vaucheriae (Kützing) Lange-Bertalot 1980
Syn: Exilaria vaucheriae Kützing 1833
Staurosira intermedia Grunow 1862
Fragilaria intermedia Grunow in Van Heurck 1881
Synedra rumpens var. meneghiniana Grunow in Van Heurck 1881
Fragilaria vaucheriae (Kützing) Petersen 1938
Valve shape highly variable, linear to lanceolate, broadly rounded to drawn out capitate ends. Central
area generally conspicuously one-sided, appearing as a swollen central nodule. Length 21 µm, width
2 (4-5) µm, striae density 9-16 (9 -14) /10 µm.
Similar species: Synedra acus (p. 148)
Synedra ulna (p. 149)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and occasionally abundant.
Predominantly found in epipelic and epilithic
assemblages but can also be planktonic. The wide
range of overlapping morphotypes present within the
complex surrounding Fragilaria capucina often
renders differentiation of individual varieties extremely
difficult.
Fig. 50. (a-c) Fragilaria capucina var. capucina: (a-b)
Hope Creek, VIC, x1700; (c) Dandenong Creek, VIC,
x1600; (d-h) var. vaucheriae; (d-f) Blind Creek, VIC;
x1500; (g) Yackandandah Creek, VIC, x1400; (h)
Hope Creek, VIC, x1700; (i) var. gracile, Meander
River, TAS, x1700.

63
Fragilariforma virescens
(Ralfs) Williams & Round 1988 (Figs 51a-d)
Synonyms: Fragilaria aequalis Heiberg 1863 sensu Grunow in Van Heurck 1881
Fragilaria virescens Ralfs 1843
Description: Valve linear, linear-elliptical to linear-lanceolate, with broadly rounded, sub-capitate to
capitate ends. Axial area straight, very narrow (may be difficult to distinguish). Central area absent. Striae
parallel in the central region, tending to slightly radial distally. Length 14-70 (10-120) µm, width 3-8 (6-
10)µm, striae 14-18 (13-19)/10 µm.
Key references: Foged 1978, p. 64, pl. 8, figs 4, 19.
Krammer & Lange-Bertalot 1991, p. 135, fig. 126: 1-10
Common varieties: None
Similar species: Nitschia angustata (Smith) Grunow in Cleve and Grunow 1880 (Not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and moderately abundant.
Recorded in both epipelic and epilithic
assemblages, although can occasionally be
planktonic. Largely restricted to dilute,
oligotrophic waters.
Fig. 51. Fragilariforma virescens: (a-b) Hope Creek, VIC, x1750; (c) Donelly River, WA, x1750; (d) girdle
view, Hope Creek, VIC, x1750.

64
Genus Frustulia
Key to the common species
1a. Margins of central area convex, length usually < 70 µm ............................................ Frustulia vulgaris
1b. Margins of central area concave to straight ......................................................... Frustulia rhomboides
Frustulia rhomboides
(Ehrenberg) De Toni 1891 (Figs 52a-c)
Synonyms: Refer to individual descriptions above.
Description: Valve rhomboid-lanceolate with broad, drawn out, rounded ends. Axial area narrow and linear,
bounded by prominent internal ribs running along either side of the raphe, giving the axial area a thickened
appearance. Axial area with 'arrow-like' distal endings. Central area variable, narrow, slightly concave.
Transapical striae finely punctate, parallel in the centre, becoming weakly convergent at the valve ends.
Striae often crossed by several delicate, irregular longitudinal lines. Length 46-78 (40-160) µm, width 10.5-
16.5 (12-30) µm, striae density 30 (20-40)/10 µm.
Key references: Foged 1978, p. 65, pl. 20, figs 5-12.
Germain 1981, p. 137, pl. 51, figs 2, 3.
Holland & Clark 1989, p. 15, pl. 9, figs 1, 4.
John 1983, p. 112, pl. 46, fig. 10.
Krammer & Lange-Bertalot 1986, p. 258, fig. 4: 2-4.
Patrick & Reimer 1966, p.306, pl. 21, figs 1, 4-8.
Thomas 1983, p. 43, pl. 6, figs 3-5.
Common varieties:
var. rhomboides
Syn: Navicula rhomboides Ehrenberg 1843
Vanheurckia rhomboides (Ehrenberg) Brébisson 1868
Nominate variety, description as above.
var. saxonica (Rabenhorst) Bacill. 1851
Syn: Frustulia saxonica Rabenhorst 1851
Valve smaller and slightly more elliptical, finer striae >35/10 µm.
var. amphipleuroides (Grunow) Cleve 1894
Syn: Navicula rhomboides var. amphipleuroides Grunow in Cleve & Grunow 1880
Axial area weakly eccentric and arcuate, central nodule noticeably elongated.
var. viridula (Brébisson) Cleve 1894
Syn: Colletonema viridulum Brébisson ex Kützing 1849
Central area margins slightly convex.

65
Frustulia rhomboides cont.
Similar species: Frustulia vulgaris (p. 66)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread in acidic waters and can be
abundant. Mostly found in epipelic and epilithic
assemblages.
Fig. 52. Frustulia rhomboides: (a-b) Hope Creek, VIC, x1700; (c) var. viridula, Shaws Creek, VIC, x1750.

66
Frustulia vulgaris
(Thwaites) De Toni 1891 (Fig. 53)
Synonyms: Refer to individual variety descriptions.
Description: Valve linear-lanceolate with broadly rounded to weakly sub-capitate ends. Axial area relatively
broad, weakly arcuate, and bounded by prominent internal ribs running along either side of the raphe. Distal
axial areas appear 'arrow-like'. Central area narrow, elliptic, margin convex. Transapical striae finely
punctate, weakly radial and less dense in the centre, becoming weakly convergent and more dense at the
valve ends. Striae often crossed by several delicate, irregular longitudinal lines. Length 47-50 (50-70) µm,
width 8-10 (10-13)µm, striae density 30-35 (23-34)/10 µm.
Key references: Foged 1978, p. 66, pl. 20, figs. 1-4.
Germain 1981, p. 140, pl. 53, figs 3-6.
Holland & Clark 1989, p. 16, pl. 9, figs 2, 3.
John 1983, p. 113, pl. 46, figs 11, 12.
Krammer & Lange-Bertalot 1986, p. 260, fig. 97: 1-6.
Patrick & Reimer 1966, p. 309, pl. 22, fig. 3.
Common varieties:
var. vulgaris
Syn: Schizonema vulgare Thwaites 1848
Vanheurckia vulgaris (Thwaites) Van Heurck 1885
Brebissonia vulgaris (Thwaites) Kuntze 1898
Nominate variety, description as above.
var capitata Krasske 1923
Valve with broadly capitate ends.
Similar species: Frustulia rhomboides (p. 64)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: More commonly found in lowland areas,
rarely abundant. Predominantly recorded in
epipelic assemblages.
Fig. 53. Frustulia vulgaris, Henty Brook, WA, x1750.

67
Genus Gomphonema
Key to the common species
1a. Valve margins distinctly undulate ........................................................................................................ 2
1b. Valves appearing otherwise ................................................................................................................. 3
2a. Head pole of valve clearly drawn out laterally from valve .......................... Gomphonema acuminatum
2b. Head pole very broadly rounded ................................................................... Gomphonema trunctatum
3a. Broadest part of valve clearly above the central node ........................................................................... 4
3b. Broadest part of valve at or around the central node ............................................................................. 6
4a. Striae density <13/10 mm ......................................................................... Gomphonema pseudoaugur1
4b. Striae density typically 14 or >in 10 mm ............................................... Gomphonema parvulum (part)
5a. Valves naviculoid (only slightly heteropolar) lanceolate, ends not drawn out from valve body. Mostly
larger forms (> 6 mm wide and > 30 mm long) ..................................................................................... 6
5b. Valves clearly bipolar, ends drawn, rostrate or capitate except in small forms (< 15 mm long) .............. 7
6a. Head pole end sharply rounded, striae density mostly >14/10 mm ....................... Gomphonema gracile
6b. Head pole end broad rounded, striae density <14/10 mm ..................................... Gomphonema affine2
7a. Head pole end broadly rounded and/or broad rostrate ........................................................................... 8
7b. Valves appearing otherwise ............................................................................................................... 10
8a. Medial striae on side opposite stigma very short or appearing absent. Axial area often narrow-lanceolate
due to gradual shortening of striae towards central area ........................ Gomphonema angustum (part)
8b. Central and axial areas appearing otherwise ......................................................................................... 9
9a. Raphe wavy, striae punctate (sometimes only indistinctly so). Head pole end occasionally forming an
undulate margin (cf. G. truncatum). Generally larger forms (> 8 mm wide and > 35 mm long) .................
........................................................................................................................ Gomphonema clavatum
9b. Valve appearing otherwise ..................................................... Other species not included in this guide
10a. Medial striae on side opposite stigma very short or appearing absent. Axial area often narrow-lanceolate
due to gradual shortening of striae towards central area ........................ Gomphonema angustum (part)
10b. Central and axial areas appearing otherwise ....................................................................................... 11
11a. Striae density usually greater than 14/10 mm, head pole end rostrate to capitate .................................12
11b. Striae density less than 14/10 mm, head pole end rostrate to broad rostrate ..............................................
.................................................................................................. Gomphonema angustatum sensu lato3
12a. Ends capitate .................................................................................................... Gomphonema lagenula
12b. Ends drawn, rostrate or subcapitate .................................................................Gomphonema parvulum
1Can be confused with G. augur (not included in this volume).
2Can be confused G. amoenum (not included in this volume)
3Reichardt (1999) suggests that type specimen of G. angustatum was incorrectly identified. This has led to substantial
confusion and, it seems, widespread incorrect assigning of several distinct taxa to this species. It is likely that the bulk
of specimens identified in Australia in the past as G. angustatum belong to the G. micropus; however, doubts
surrounding the identification of these diatoms make it impossible to make accurate assessments of either the ecology or
the distribution of G. micropus. Accordingly, neither G. angustatum sensu lato, nor G. micropus are included in this
volume.

68
Gomphonema acuminatum
Ehrenberg 1832 (Figs 54a-b)
Synonyms: Gomphonema brebissonii Kützing 1849
Description: Valve wedge-shaped, with noticeable constrictions above and below the middle of the valve.
Head pole broadly apiculate, whereas foot pole narrow, drawn out and rounded. Axial area narrow. Central
area transverse,with shortened striae on one or both sides of the central area. A single medial stria almost
reaching the central nodule, terminating with an isolated stigma. Striae generally punctate, weakly radiate in
middle of valve, tending to strongly radiate distally. Length 50 (20-120) µm, width 12 (5-17) µm, striae
density 12 (8-13)/10 µm.
Key references: Foged 1978, p. 67, pl. 41, fig. 9.
Holland & Clark 1989, p. 16, pl. 10, fig. 6.
John 1983, p. 141, pl. 59, figs 1,2.
Krammer & Lange-Bertalot 1986, p. 365, fig. 160: 1-12.
Patrick & Reimer 1975, p. 112, pl. 15, figs 2, 4, 7.
Common varieties: None
Similar species Gomphonema coronatum Ehrenberg 1840 (Not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 54. Gomphonema acuminatum: (a)
Loddon River, VIC, x1750; (b) Genoa River,
VIC, x1700.
Notes: Widespread distribution but not usually abundant.
Mostly recorded in epilithic assemblages.

69
Gomphonema affine
Kützing 1844 (Figs 55a-c)
Synonyms: Gomphonema lanceolatum sensu Hustedt 1927-1966
Description: Valve clavate to lanceolate, with bluntly rounded head pole and attenuate, rounded foot pole.
Axial area broad and linear. Raphe prominent, often conspicuously wavy. Central area small, transverse,
distinctly one-sided with a shortened medial stria on one side. An isolated stigma is located adjacent to the
central nodule on the opposite side to the shortened stria. Transapical striae more widely spaced, parallel to
weakly radial in the central region, becoming more closely spaced and increasingly radial distally. Striae
coarsely punctate. Length 42-65 (30-100) µm, width 10-11 (7-12) µm, striae density 18-24 (8-13)/10 µm.
Key references: John 1883, p. 141, pl. 59, figs 3, 4.
Krammer & Lange-Bertalot 1986, p. 366, fig. 161; 1-3.
Patrick & Reimer 1975, p. 133, pl. 17, fig. 5.
Common varieties: None
Similar species: Gomphonema clavatum (p. 71)
Gomphonema gracile (p. 72)
Gomphonema parvulum (p. 74)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 55. (a-b) Gomphonema affine: (a)
Loddon River, VIC, x1750; (b) Adelong
River, NSW, x1750; (c) Gomphonema
affine?, Torrens River, SA, x1750.
Notes: Widespread, particularly in lowland areas, but
rarely abundant. Mostly recorded in epiphytic
assemblages.

70
Gomphonema angustum
Agardh 1831 (Figs 56a-c)
Synonyms: Gomphonema dichotomum Kützing 1834
Gomphonema intricatum Kützing 1844
Gomphonema bohemicum Reichelt & Fricke 1902
Gomphonema fanensis Maillard 1964
Description: Valve extremely variable in shape, ranging from linear-clavate, lanceolate elliptical to linear-
elliptical, with bluntly rounded to broadly subcapitate head pole and narrowly rounded foot pole. Valve often
with swollen central region. Raphe filiform, straight to undulate. Axial area relatively broad, widening
towards the central area. Central area widely transverse, with an extremely shortened medial stria on one or
both sides. An isolated stigma is located adjacent to the central nodule. Transapical striae weakly radial
throughout valve, generally more widely spaced in the central region. Striae ± distinctly punctate under LM.
Length 17-22 (12-130) µm, width 3.5-4 (3-12) µm, striae density 12/10 µm.
Key references: Germain 1981, p. 304, pl. 113, figs 1-5
Krammer & Lange-Bertalot 1986, p. 370, fig. 164: 1-16..
Patrick & Reimer 1975, p. 22, pl. 18, figs 1-3.
Common varieties: None
Similar species:Gomphonema affine (p. 69)
Gomphonema clavatum (p. 71)
Gomphonema parvulum (p. 74)
Gomphonema pumilum Reichardt & Lange-Bertalot 1991 (Not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 56. Gomphonema angustum: (a)
Plenty River, VIC, x2200; (b) Adelong
River, NSW, x1750; (c) Meander River,
TAS, x1750.
Notes: Associated with middle order streams, not usually
abundant. Commonly epiphytic but also can be found in
epipelic and epilithic assemblages.

71
Gomphonema clavatum
Ehrenberg 1832 (Figs 57a-c)
Synonyms: Gomphonema longiceps Ehrenberg 1854
Gomphonema mustela Ehrenberg 1854
Gomphonema montanum Schumann 1867
Gomphonema subclavatum (Grunow) Grunow in Van Heurck 1885
Gomphonema commutatum Grunow in Van Heurck 1880
Gomphocymbella obliqua (Grunow) O. Mülller 1905
Description: Valve clavate, with broadly rounded head pole and strongly narrowed foot pole. Valve
sometimes with distinct constriction above and below centre. In girdle view, wedge -shaped and with
several lines of coarse punctae extending along the valve margins and girdle bands. Axial area broad and
linear. Raphe filiform and sinuous. Central area small, circular to rhomboid, with one or two slightly
shortened central striae on either side. An isolated stigma is present on one side of the central nodule.
Transapical striae slightly radial in the centre, becoming increasingly radial at the ends. Striae usually
distinctly punctate. Length 42-58 (20-95) µm, width 8 (6-14) µm, striae density (9-15)/10 µm.
Key references: Germain 1981, p. 304, pl. 111, fig. 13.
Krammer & Lange-Bertalot 1986, p. 367, fig. 163; 1-12.
Patrick & Reimer 1975, p. 129, pl. 16, fig. 10.
Common varieties: There is a number of varieties of G. clavatum described in the literature. None of these
have been differentiated in Australian streams.
Similar species: Gomphonema parvulum (p. 74)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 57. Gomphonema clavatum: (a-b) Hope
Creek, VIC, x1750; (c) Goulburn River, VIC,
x1800.
Notes: Widespread and can be moderately abundant.
Commonly epiphytic but can be found in epipelic and
epilithic assemblages.

72
Gomphonema gracile
Ehrenberg 1838 (Figs 58a-c)
Synonyms: Gomphonema lanceolatum Ehrenberg 1841
Gomphonema grunowii Patrick & Reimer 1975
Description: Valve distinctly lanceolate, almost iso-polar, with long narrowly tapered, acutely pointed head
and foot poles. Axial area narrow and linear. Raphe filiform, slightly arcuate to undulate. Central area small,
transverse, on one-side a shortened medial stria, on the other side a medial stria ending in an isolated stigma.
Transverse striae almost parallel in the central region to weakly radial throughout the rest of the valve. Striae
adjacent to the central area more widely spaced. Striae ± distinctly punctate under LM. Length 31-48 (20-
100) µm, width 5-7 (4-11) µm, striae density 13-14 (9-17)/10 µm.
Key references: Foged 1978, p. 69, pl. 39, fig. 7, pl. 40, figs 21, 22, 24, pl. 41, fig. 8.
Germain 1981, p. 310, pl. 115, figs 1-14.
Holland & Clark 1989, p. 16, pl. 9, fig. 10, pl. 10, fig. 18, pl. 11, fig. 9.
Krammer & Lange-Bertalot 1986, p. 361, figs , 154: 26, 27, 156: 1-11.
Patrick & Reimer 1975, p. 131, pl. 17, figs 1-3, 6.
Thomas 1983, p. 44, pl. 6, fig. 8.
Common varieties: None
Similar species: Gomphonema affine (p. 69)
Gomphonema amoenum (Not described in this guide)
Gomphonema clavatum (p. 71)
Gomphonema insigne (Not described in this guide)
Gomphonema parvulum (p. 74)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 58. Gomphonema gracile: (a-c) Valencia
Creek, VIC, x1600.
Notes: Widespread but rarely abundant. Mostly found
attached to epiphytes but can be found in epilithic and
epipelic assemblages.

73
Gomphonema lagenula
Kützing 1844 (Figs 59a-c)
Synonyms: Gomphonema parvulum var. lagenula ( Kutzing) Frenguelli 1923
Description: Valve extremely variable in shape, from clavate-lanceolate, lanceolate to elliptical with
narrow, drawn out capitate ends. Axial area narrow, raphe filiform, straight to slightly sinuous. Central area
absent or one-sided, one side with distinctly shortened stria, the other side with a slightly shortened stria
ending with an isolated stigma. Striae almost parallel in the central region becoming radial towards the valve
ends. The medial striae more widely spaced than others. Length 23-26 (10-36) µm, width 6-7.5 (4-8) µm,
striae density 12-16 (7-20)/10 µm.
Key references: Foged 1978, p. 71, pl. 40, figs 10,11.
Krammer & Lange-Bertalot 1986, p. 358, fig. 154: 8-10.
Patrick & Reimer 1975, p. 123, pl. 17, fig 9.
Common varieties: None
Similar species: Gomphonema parvulum (p. 74)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Very widespread and is often abundant, to the
point of completely dominating a sample. Often co-
occurs with G. parvulum. Due to its recent separation
from G. parvulum, there is a paucity of local ecological
data for this species. It is given the same index values
as G. parvulum here on the basis of their frequent co-
occurrence, Found in epiphytic, the epipelic and
epilithic assemblages.
Fig. 59. Gomphonema lagenula: (a-b) Dawesley Creek, SA, x1750; (c) Blackwood River, WA, x1750.
.

74
Gomphonema parvulum
Kützing 1849 (Figs 60a-f)
Synonyms: Sphenella parvula Kützing 1844
Description: Valve extremely variable in shape, from clavate-lanceolate, lanceolate to elliptical with
narrow, drawn to subrostrate ends. Axial area narrow, raphe filiform, straight to slightly sinuous. Central
area absent or one-sided, one side with distinctly shortened stria, the other side with a slightly shortened stria
ending with an isolated stigma. Striae almost parallel in the central region becoming radial towards the valve
ends. The medial striae more widely spaced than others. Length 16-33 (10-36) µm, width 5.5-7.5 (4-8) µm,
striae density 11-17 (7-20)/10 µm.
Key references: Foged 1978, p. 71, pl. 40, figs 12-15.
Germain 1981, p. 308, pl. 114, figs 23-28.
Holland & Clark 1989, p. 17, pl. 10, figs 13-16.
John 1983, p. 142, pl. 59, figs 7-9.
Krammer & Lange-Bertalot 1986, p. 358, fig. 154: 1-7, 11-25.
Patrick & Reimer 1975, p. 123, pl. 17, figs 7, 8, 10-12.
Thomas 1983, p. 44, pl. 6m, figs 10-12.
Common varieties: None
Similar species Gomphonema angustum (p. 70)
Gomphonema clavatum (p. 71)
Gomphonema lagenula (p. 73)
Gomphonema micropus Kützing 1844 (Not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Very widespread and is often abundant, to the
point of completely dominating a sample. This taxon’s
broad tolerance, particularly for nutrients, may reflect
the existence of different morphotypes with distinct
ecological parameters. Recorded in epiphytic, epipelic
and epilithic assemblages.
Fig. 60. Gomphonema parvulum: (a-b) Dawesley Creek, SA, x1750; (c) Adelong River, NSW, x1750; (d)
Dandenong Creek, VIC, x1750, (e) Inman River, SA, x1750; (f) Dawesley Creek, SA, x1750.

75
Gomphonema pseudoaugur
Lange-Bertalot 1979 (Figs 61a-c)
Synonyms: None
Description: Valve elliptical to elliptical-lanceolate, with a broadly rounded, subrostrate head pole, and
acutely tapered, rounded to subrostrate/subcapitate foot pole. Valve markedly wider above the middle of the
valve. Axial area narrow and linear. Raphe filiform. Central area small, transverse, with a slightly shortened
medial stria on one side, and with the medial stria terminated with an isolated stigma on the other side.
Transapical striae parallel to weakly radial in the centre, weakly radial elsewhere on the valve. Striae in the
central area just slightly wider than the rest of the valve. Striae indistinctly punctate. Length 17-35 (25-55)
µm, width 6.5-9 (7-10) µm, striae density 10-14 (9-12)/10 µm.
Key references: Krammer & Lange-Bertalot 1986, p. 364, fig. 159: 1-4.
Common varieties: None
Similar species: Gomphonema augur Ehrenberg 1840 (Not described in this guide)
Gomphonema gracile (p. 72)
Gomphonema parvulum (p. 74)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widepsread and usually confined to nutrient
rich waters. Recorded in epipelic, epilithic and
epiphytic assemblages.
Fig. 61. Gomphonema pseudoaugur: (a-c) Dandenong Creek, VIC, x2100.

76
Gomphonema truncatum
Ehrenberg 1832 (Figs 62a-b)
Synonyms: Refer to individual variety descriptions.
Description: Valve large and broadly clavate, head pole broadly rounded-capitate, strongly convex at
middle of valve, tapering to a narrow foot pole. Axial area broad, raphe distinctly sinuous. Central area
transapically broadened, with alternating short and long striae (sometimes appearing stellate), usually with
1-5 stigma adjacent to the central area. Striae strongly punctate, weakly radial, density 13 (9-12)/10 µm.
Striae in central area may be more widely spaced. Length 33 (13-75) µm, width 12 (7-17) µm.
Key references: Germain 1981, p. 301, pl. 112, figs 1-12.
John 1983, p. 143, pl. 59, figs 10-14.
Krammer & Lange-Bertalot 1986, p. 369, fig. 159: 11-18.
Patrick & Reimer 1975, p. 118, pl. 16, figs 3-5, 8.
Common varieties:
var. truncatum
Syn: Gomphonema constrictum Ehrenberg 1832
Gomphonema constrictum var. subcapitata Grunow 1880
Nominate variety, description as above.
var. capitatum (Ehrenberg) Patrick 1975
Syn: Gomphonema capitatum Ehrenberg 1838
Valve with less capitate head pole and more weakly radiate striae than var. truncatum.
var. turgidum (Ehrenberg) Patrick 1975
Syn: Gomphonema turgidum Ehrenberg 1854
Variety distinguished by broad, truncated valve.
Similar species: Gomphonema clavatum (p. 71)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 62. Gomphonema truncatum: (a) Loddon
River, VIC, x1750; (b) Valencia Creek, VIC,
x1700.
Notes: Widespread throughout most streams, although
rarely abundant. Mostly found in epiphytic
assemblages.

77
Genus Gyrosigma
Key to the common species
1a. Longitudinal striae < 13/10 mm, coarser than transverse striae ........................... Gyrosigma attenuatum
1b. Longitudinal striae > 13/10 mm ............................................................................................................ 2
2a. Longitudinal and transverse striae of equal density (< 20/10 mm) .................... Gyrosigma acuminatum
2b. Longitudinal striae > 20/10 mm, transverse striae usually coarser .......................... Gyrosigma spencerii
Gyrosigma acuminatum
(Kützing) Rabenhorst 1853 (Fig. 63)
Synonyms: Frustulia acuminata Kützing 1833
Navicula acuminata Kützing 1844
Pleurosigma acuminatum (Kützing) Grunow 1860
Description: Valve sigmoid, lanceolate, with attenuated, rounded ends. Axial area narrow and central.
Central area narrowly elliptical. Raphe filiform, proximal ends deflected in opposite directions. Longitudinal
and transverse striae almost equally spaced. Length 91-105 (60-180) µm, width 13 (11-18) µm, striae density
18 (16-22)/10 µm.
Key references: Germain 1981, p. 132, pl. 49, figs 2-5.
Krammer & Lange-Bertalot 1986, p. 296, figs 114: 4, 8.
Patrick & Reimer 1966, p. 314, pl. 23, figs 1-3.
Common varieties: None
Similar species: Gyrosigma attenuatum (p. 78)
Gyrosigma spencerii (p. 79)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread though rarely abundant. More
common in lowland and foothill areas. Recorded in
epipelic and epilithic assemblages.
Fig. 63. Gyrosigma acuminatum, Inman River, SA, x1700.

78
Gyrosigma attenuatum
(Kützing) Rabenhorst 1853 (Fig. 64)
Synonyms: Frustulia attenuata Kützing 1833
Pleurosigma attenuatum (Kützing) W. Smith 1852
Description: Valve sigmoid, lanceolate, with attenuated, rounded ends. Axial area narrow and central.
Central area small and elliptical. Raphe filiform with proximal ends deflected in opposite directions.
Longitudinal striae much coarser than the transverse striae. Length 210 (150-240) µm, width 24 (23-26) µm,
longitudinal striae 11 (10-12)/10 µm, transverse striae 13 (14-16)/10 µm.
Key references: Foged 1978, p. 73, pl. 21, figs 3, 4.
Germain 1981, p. 132, pl. 49, fig. 1.
Holland & Clark 1989, p. 17, pl. 12, fig. 2.
Krammer & Lange-Bertalot 1986, p. 297, figs 114: 5, 7.
Patrick & Reimer 1966, p. 319, pl. 24, fig. 1.
Thomas 1983, p. 45, pl. 8, fig. 7.
Common varieties: None
Similar species: Gyrosigma acuminatum (p. 77)
Gyrosigma spencerii (p. 79)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread though rarely abundant. More
common in lowland and foothill areas. Recorded in
epipelic and epilithic assemblages. Often associated
with G. acuminatum.
Fig. 64. Gyrosigma attenuatum, Mullaroo Creek, VIC, x1300.

79
Gyrosigma spencerii
(Quekett) Griffith & Henfrey 1856 (Fig. 65a-b)
Synonyms: Navicula spencerii Quekett 1848
Pleurosigma spencerii (Quekett) W. Smith 1852
Pleurosigma kutzingii Grunow 1860
Pleurosigma gracilentum Rabenhorst 1864
Gyrosigma kützingii (Grunow) Cleve 1894
Description: Valve sigmoid, lanceolate, with narrow, drawn out rounded ends. Axial area narrow and
slightly undulate. Proximal raphe ends close, deflected in opposite directions. Terminal raphe ends eccentric.
Central area elliptical. Longitudinal and transverse striae equally 'distinct', transverse striae slightly more
coarse. Length 70-80 (70-220) µm, width 10-12 (12-25) µm, longitudinal striae 20-22 (22-26)/10 um,
transverse striae 20-22 (17-23)/10 um.
Key references: Germain 1981, p. 134, pl. 49, figs 6-8.
John 1983, p. 115, pl. XLVII, figs 7,8, pl. 48, figs 4-6.
Krammer & Lange-Bertalot 1986, p. 298, fig. 115: 2.
Patrick & Reimer 1966, p. 315, pl. 23, fig. 4.
Common varieties: None
Similar species: Gyrosigma acuminatum (p. 77)
Gyrosigma attenuatum (p. 78)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread though rarely abundant. More
common in lowland and foothill areas. Recorded in
epipelic and epilithic assemblages.
Fig. 65. Gyrosigma spenceri: (a) Mullaroo Creek,VIC, x1550; (b) Adelong River, NSW, x2000.

80
Hantzschia amphioxys
(Ehrenberg) Grunow 1877 (Fig. 66a)
Synonyms: Eunotia amphioxys Ehrenberg 1841
Description: Valve linear to linear-lanceolate, slightly dorsiventral (asymmetrical about the apical plane)
with rounded capitate ends. Valve with a weakly convex dorsal margin, and concave ventral margin. Raphe
canal highly fibulate, located on the ventral margin of both valves (ie. same side, cf. Nitzschia sp). Fibulae
coarse, irregularly spaced, and with a central nodule. Transapical striae extremely fine, and parallel. Length
31 (20-300) µm, width 5 (5-25) µm, fibulae density (4-11)/10 µm, striae density 25 (11-28)/10 µm.
Key references: Foged 1978, p. 75, pl. 43, figs 3, 5, 8.
Germain 1981, p. 326, pl. 122, figs 2-10.
Holland & Clark 1989, p. 18, pl. 12, figs, 3, 6, pl. 13, fig. 1.
John 1983, p. 163, pl. 68, figs 8, 9.
Krammer & Lange-Bertalot 1988, p. 128, fig. 88: 1-7.
Thomas 1983, p. 46, pl. 11, fig. 6, pl. 13, fig. 1.
Common varieties: None
Similar species: Hantzschia abundans Lange-Bertalot 1993 (fig. 66b)
Ecological preferences:
TP
EC
pH
12 3 4 5
Notes: Widespread but not usually abundant.
Commonly aerophilous. Recorded in both epipelic and
epilithic assemblages.
Fig. 66. (a) Hantzschia amphioxys, Murrumbidgee River, NSW, x1800; (b) Hantzschia abundans, Loddon
River, VIC, x1750.

81
Genus Luticola
Key to the common species
1a. Stigma located on one side of the central area near the margin ...................................... Luticola mutica
1b. Slightly elongated stigma to one side of the central area approximately halfway between the axial area
and the valve margin .......................................................................................... Luticola goeppertiana
Luticola goeppertiana
(Bleisch in Rabenhorst) Mann 1990 (Figs 67a-c)
Synonyms: Stauroneis goeppertiana Bleisch in Rabenhorst 1861
Navicula mutica var. goeppertiana (Bleisch) Grunow in Van Heurck 1880
Navicula terminata Hustedt 1966
Navicula goeppertiana (Bleisch) H.L. Smith 1874-1879
Description: Valve elliptical-lanceolate to rhomboid-lanceolate, with blunt to sharply, rounded ends. Axial
area lanceolate. Raphe prominent and straight, proximal ends turned to one side. Central area transapically
widened, forming a fascia which almost extends to the valve margins. A prominent, transapically elongate
stigma is present on one side of the central area approximately halfway between the axial area and the valve
margin. Striae adjacent to the central area extremely short. Transapical striae distinctly punctate, and radial
along entire length of valve. Length 20 (10-144) µm, width 6.5 (6-36) µm, striae density 20 (18-24)/10 µm.
Key references: Foged 1978, p. 94, pl. 28, figs 13, 14, pl. 29, fig. 5.
Germain 1981, p. 209, pl. 79, figs 8-13.
Krammer & Lange-Bertalot 1986, p. 150, fig. 62: 1-12.
Common varieties: None
Similar species: Luticola mutica (p. 82)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 67. Luticola goeeppertiana: (a-c)
Gardiners Creek, VIC, x2000.
Notes: Widespread and moderately abundant. Reliable
indicator of organic pollution. Predominantly
aerophilous but can also be found in epiphytic
assemblages.

82
Luticola mutica
(Kützing) Mann 1990 (Figs 68a-c)
Synonyms: Refer to individual variety description.
Description: Valve lanceolate to rhomboid-elliptical, with broadly rounded ends. Axial area narrow, raphe
straight to slightly arcuate, proximal ends just turned to the same side. Central area large, transapically
widened, almost to the valve margin. A distinct stigma is present near the margin on one side of the central
area. Striae opposite the central area extremely short and irregular. Striae coarsely punctate and radial
throughout the valve. Length 14-20 (6-30) µm, width 5.5-7.5 (4-9) µm, striae density 20-22 (14-20)/10 µm.
Key references: Foged 1978, p. 93, pl. 28, figs 10, 11.
Germain 1981, p. 209, pl. 79, figs 1-4.
Holland & Clark 1989, p. 20, pl. 14, figs 9, 13-17.
John 1983, p. 94, pl. 40, figs 5-11.
Krammer & Lange-Bertalot 1986, p. 149, figs 53: 8-9, 61: 1-11.
Patrick & Reimer 1966, p. 454, pl. 42, fig. 2.
Thomas 1983, p. 52, pl. 7, fig. 13.
Common varieties:
var. mutica
Syn: Navicula mutica Kützing 1844
Stauroneis rotaeana Rabenhorst 1856
Stauroneis goeppertiana Bleisch ex Rabenhorst 1864
Navicula imbricata Bock 1963
Nominate variety described above.
var. ventricosa (Kützing) Cleve & Grunow 1880
Syn: Stauroneis ventricosa Kützing 1844
Navicula neoventricosa Hustedt 1966
Valve with sub-capitate to capitate ends.
Similar species: Luticola goeppertiana (p. 81)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 68. Luticola mutica: (a) Inman River,
SA, x1750; (b-c) Plenty River, VIC, x2000.
Notes: Widespread and moderately abundant. Reliable
indicator of organic pollution. More common than L.
goeppertiana. Aerophilous but can also be found in
epiphytic assemblages.

83
Melosira varians
Agardh 1827 (Figs 69a-b)
Synonyms: Gallionella varians Ehrenberg 1836
Description: Cells cylindrical, valve face circular, appearing either flat or slightly domed. Valve surfaces
lacking distinct ornamentation, therefore often appearing smooth, sometimes pitted, under the LM. Cells
often forming long filaments, attaching end to end via mucilage pads secreted onto the valve faces. Valve
diameter 8-24 (8-35) µm, height 8-11 (4-14) µm.
Key references: Foged 1978, p. 83, pl. 1, fig. 12.
Germain 1981, p. 22, pl. 2, figs 9, 10.
Holland & Clark 1989, p. 18, pl. 14, fig. 6.
John 1983, p. 17, pl. 11, fig. 10.
Krammer & Lange-Bertalot 1991, p. 7, figs 3, 4: 1-8, 8.
Common varieties: None
Similar species: None
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and occasionally very abundant.
Typically a lowland taxon. Most commonly found in
epilithic assemblages, and seems to prefer shaded
sections of streams.
Fig. 69. Melosira varians: (a) valve view, Bremer River, SA, x1750; (b) girdle view, Tookeyerta Creek, SA,
x1750.

84
Genus Navicula and related genera
Key to common species
1a. Valve with conspicuously wide striae, less than 10/10 µm, not punctate, valve length generally less
than 30 µm ................................................................................................................ Navicula capitata
1b. Valve appearing otherwise ....................................................................................................................2
2a. Valve elliptical, ................................................................................................................................... 3
2b. Valve linear to lanceolate .................................................................................................................... 4
3a. Striae strongly radial (sometimes difficult to see), central and distal nodules conspicuous .......................
................................................................................................................................ Mayamaea atomus
3b. Striae parallel to weakly radial, central area absent ........................................... Eolimna subminuscula
4a. Striae weakly radial to almost parallel .................................................................................................5
4b. Striae clearly radial .............................................................................................................................. 7
5a. Striae density greater than 20/10 µm, less densely spaced at centre ................... Navicula molestiformis
5b. Striae density less than or equal to 20/10 µm ....................................................................................... 6
6a. Striae continuously radial to the valve ends ............................................................ Navicula schroeterii
6b. Striae radial, tending to parallel or convergent at the valve ends ........................................................... 7
7a. Proximal raphe ends clearly deflected to one side, so that the central nodule is clearly enlarged ........... 8
7b. Central nodule not deflected to one side ............................................................................................. 11
8a. Valve ends broadly rounded, rarely pointed ......................................................................................... 9
8b. Valve ends more or less drawn, often subcapitate .............................................................................. 10
9a. Striae in central area strongly radial, length greater than 40 µm ....................... Navicula heimansioides
9b. Striae in central area weakly radial, length always less than 40 µm ............................ Navicula erifugia
10a. Striae 7-10/10 µm ...................................................................................................... Navicula viridula
10b. Striae 13-22/10 µm ................................................................................................... Navicula gregaria
11a. Valve width less than 4 µm .................................................................................... Navicula tenelloides
11b. Valve width greater than 4 µm ........................................................................................................... 12
12a. Central area distinctly rectangular ................................................................................ Navicula veneta
12b. Central area otherwise formed ........................................................................................................... 13
13a. Valve ends drawn out, capitate to rostrate .......................................................................................... 14
13b. Valve appearing otherwise ................................................................................................................. 15
14a. Central striae alternately shorter and longer ........................................................... Navicula salinarum
14b. Central striae appearing otherwise, widely spaced ......................................... Navicula rhynchocephala
15a. Central area rhomboid ................................................................................................ Navicula radiosa
15b. Central area appearing otherwise ....................................................................................................... 16
16a. Central area small and irregular, ends sharply rounded ........................................................................17
16b. Central area large ...............................................................................................................................18
17a. Valve width 5-7 um, narrowly lanceolate ........................................................... Navicula cryptotenella
17b. Valve width 7.5-12 µm ......................................................................................... Navicula menisculus

85
18a. Central striae alternately shorter and longer .................................................................. Navicula recens
18b. Central striae appearing otherwise ......................................................................................................19
19a. Striae 14-18/10 µm, width 5-7 µm, ends elongated to sub-capitate ................... Navicula cryptocephala
19b. Striae 10-14/10 µm, width 9-12 µm, ends more rounded ........................................ Navicula lanceolata
Eolimna subminuscula
(Grunow) Lange-Bertalot 1997 (Figs 70a-c)
Synonyms: Navicula luzonensis Hustedt 1942
Navicula demissa Hustedt 1945
Navicula frugalis Hustedt 1957
Navicula subminuscula Manguin 1941
Description: Valve elliptical to rhomboid-elliptical, with sharply rounded to subrostrate ends. Axial area
relatively broad and linear. Raphe straight to weakly curved, so that the proximal ends are slightly turned to
the same side. Central area absent. Transapical striae parallel to radial throughout, sometimes spaced further
apart in the central area. Striae finely punctate but not usually obvious under LM. Length 11-11.5 (7-12.5)
µm, width 4-5 (3.5-6) µm, striae density 18-21 (15-26)/10 µm.
Key references: Germain 1981, p. 227, pl. 85, figs 8-10.
Krammer & Lange-Bertalot 1986, p. 223, fig. 76: 21-26.
Common varieties: None
Similar species: Craticula accomoda (p. 30)
Navicula molestiformis (p. 95)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be moderately
abundant. Good indicator of organic pollution.
Found in epipelic and epilithic assemblages.
Fig. 70. Eolimna subminuscula: (a-c) Dawesley Creek, SA, x1750.

86
Hippodonta capitata
(Ehrenberg) Lange Bertalot, Witkowski & Metzeltin 1996 (Figs 71a-b)
Synonyms: Navicula capitata Ehrenberg 1838
Navicula humilis Donkin 1870-1873
Navicula hungarica var. capitata (Ehrenberg) Cleve 1895
Description: Valve elliptical, elliptical-lanceolate to rhomboid-lanceolate, with broadly rounded to drawn
out sub-rostrate to sub-capitate ends. Axial area narrow, raphe filiform. Central area small, usually formed by
one slightly shortened stria on either side of the central area. Striae conspicuously wide and coarse, radial in
the central area becoming convergent at the ends. Valve ends without striae, therefore appearing hyaline.
Striae with double rows of punctae. Punctae usually not visible under LM. Length 17-18 (10-47) µm, width 6
(4-10) µm, striae density 8-9 (8-11)/10 µm.
Key references: Germain 1981, p. 186, pl. 71, fig. 5.
Holland & Clark 1989, p. 19, pl. 16, fig. 10.
John 1983, p. 84, pl. 37, figs 4, 5.
Krammer & Lange-Bertalot 1986, p. 123, fig. 1-11.
Patrick & Reimer 1966, p. 536, pl. 52, figs 1-4.
Common varieties: None
Similar species: Pinnularia borealis (p. 126)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be moderately abundant.
Mostly found in epipelic and epilithic assemblages.
Fig. 71. Hippodonta capitata: (a-b) Dawesley Creek, SA, x1750.

87
Mayamaea atomus
(Kützing) Lange & Bertalot 1997 (Fig. 72)
Synonyms: Refer to individual variety descriptions.
Description: Valve elliptical to somewhat elliptical -lanceolate, with rounded ends. Axial area broad,
lanceolate in shape and appearing heavily silicified. Raphe often with prominent distal nodule that appears to
be located short of the valve ends. Central area absent or slightly transverse. Striae widely spaced in the
central region and strongly radial throughout the valve. Striae, when visible, may appear punctate. Length 7-
10.5 (5.5-16) µm, width3-4 (3-6.5) µm, striae density (16-36)/10 µm.
Key references: Germain 1981, p. 232, pl. 85, figs 38, 39.
Krammer & Lange-Bertalot 1986, p. 216, fig. 74: 10-28.
Patrick & Reimer 1966, p. 488, pl. 46, fig. 15.
Common varieties:
var. atomus
Syn: Amphora atomus Kützing 1844
Synedra atomus Naegeli ex Kützing 1849
Navicula atomus (Kützing) Grunow 1860
Navicula caduca Hustedt 1942
Navicula pseudoatomus Lund 1946
Nominate variety, refer to description as above.
var. permitis (Hustedt) Lange-Bertalot 1985
Syn: Navicula permitis Hustedt 1945
Navicula peratomus Hustedt 1957
Striae fine, often not visible under LM
var. excelsa (Krasske) Lange-Bertalot 1985
Syn: Navicula excelsa Krasske 1925
Proximal raphe nodules absent, striae visibly punctate and more widely spaced in the central region.
Similar species: None
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 72. Mayamaea atomus, Dandenong
Creek, Vic, x1900.
Notes: Widespread and can be abundant, particularly in
high nutrient waters. Mostly inhabits epilithic and epipelic
habitats.

88
Navicula cryptocephala
Kützing 1844 (Figs 73a-b)
Synonyms: Refer to individual variety descriptions.
Description: Valve lanceolate with drawn out, subrostrate to subcapitate ends. Axial area narrow and
straight, widening slightly towards the centre. Proximal raphe ends straight. Central area distinct, roughly
circular, formed by gradually shortened striae. Striae in the central region strongly radial, becoming
convergent at the ends. Striae lineolate, but not usually seen under LM. Length 23-29 (20-40) µm, width 6
(5-7) µm, striae 12-14 (14-17)/10 µm.
Key references: Foged 1978, p. 86, pl. 31, fig. 12.
Germain 1981, p. 188. Pl. 72, figs 1-5.
Holland & Clark 1989, p. 19. pl. 16, figs 13, 21.
John 1983, p. 87, pl. 38, figs 3,4.
Krammer & Lange-Bertalot 1986, p. 102, fig. 31: 8-14.
Patrick & Reimer 1966, p. 503, pl. 48, fig. 3.
Common varieties:
var. cryptocephala
Syn: Navicula exilis Kützing 1844
Nominate variety, description as above.
var. exilis (Kützing) Grunow in Van Heurck 1880
Syn: Navicula exilis Kützing 1844
Navicula cryptocephala var. exilis (Kützing) Grunow in Van Heurck 1880
Valve generally shorter and with slightly higher striae density.
Similar species: Navicula capitatoradiata Germain 1981 (not described in this guide)
Navicula cryptotenella (p. 89)
Navicula radiosa (p. 96)
Navicula rhynchocephala (p. 98)
Navicula veneta (p. 101)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 73. Navicula cryptocephala: (a)
Blackwood River, WA, x1750; (b) Dawesley
Creek, SA, x1750.
Notes: Widespread and occasionally moderately
abundant. Mostly found in epipelic assemblages. This
is a polymorphic taxon and may be confused with
other lanceolate Navicula species.

89
Navicula cryptotenella
Lange-Bertalot 1985 (Figs 74a-c)
Synonyms: Navicula tenella Brébisson ex Kützing 1849
Navicula radiosa var. tenella (Brébisson ex Kützing) Van Heurck 1885
Description: Valve lanceolate to rhomboid-lanceolate with acute, rounded ends. Axial area narrow, straight,
slightly widened towards the centre. Raphe filiform, proximal ends straight. Central area small and
irregularly bordered (Krammer & Lange-Bertalot, 1986). Striae in central area alternately shorter and longer,
the medial striae generally being longer than the rest. Striae radial in the centre, and parallel to convergent
distally. Striae finely lineolate, > 35/10 µm, but rarely seen under LM. Length 20-40 (14-40) µm, width 5-7
(5-7) µm, striae density 15-16 (14-16)/10 µm.
Key references: Krammer & Lange-Bertalot 1986, p. 106, fig. 33: 9-11.
Patrick & Reimer 1966, p. 510, pl. 48, fig. 17.
Common varieties: None
Similar species: Navicula menisculus (p. 94)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread though rarely abundant. More
common in lowland and foothill areas. Found in
epipelic and epilithic assemblages.
Fig. 74. Navicula cryptotenella: (a) Latrobe River, VIC, x1800; (b-c) Kiewa River, VIC, x1800.

90
Navicula erifuga
Lange-Bertalot 1985 (Figs 75a-b)
Synonyms: Navicula leptocephala Brébisson ex Grunow in Van Heurck 1880
Navicula cincta var. leptocephala (Brébisson) Van Heurck 1885
Navicula heurflerii var. leptocephala (Brébisson) Peragallo 1897-1908
Description: Valve lanceolate to linear-lanceolate, with acute to bluntly pointed ends. Axial area narrow,
slightly widening toward the central area. Raphe filiform, straight or slightly arcuate. Proximal raphe ends
turned to the same side. Central area circular to sub-rectangular, often distinctly one-sided, reaching to
approximately one third of the distance to valve margins. Striae in the central region weakly radial and more
widely spaced, becoming convergent at the valve ends. Punctae not generally visible. Length 22-31 (25-35)
µm, width 5-8 (5-7) µm, striae density 10-14 (12-14)/10 µm.
Key references: Krammer & Lange-Bertalot 1986, p. 116, fig. 38: 5-9.
Common varieties: None
Similar species: Navicula cryptocephala (p. 88)
Navicula schroeterii (p. 99)
Navicula veneta (p. 101)
Navicula viridula (p. 101)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread though rarely abundant. More
common in urban streams. Recorded in both epipelic
and epilithic assemblages.
Fig. 75. Navicula erifugia; (a-b) Dawesley Creek, SA, x1750.

91
Navicula gregaria
Donkin 1861 (Figs 76a-d)
Synonyms: Navicula gregalis Cholnoky 1963
Description: Valve lanceolate with drawn out capitate to rostrate ends. Axial area narrow, raphe filiform
and slightly curved to one side. Proximal raphe ends deflected to one side. Central area extremely variable in
size, from small and indistinct to conspicuously one-sided. Margins of the central area often appearing
straight due to several equally shortened striae. Striae parallel to slightly radial in the central area, becoming
slightly convergent distally. Striae punctate, although not always obvious. Length 22-30 (13-42) µm, width
5-6 (5-10) µm, striae density 14-18 (13-22)/10 µm.
Key references: Foged 1978, p. 90, pl. 30, fig. 8.
Germain 1981, p. 170, pl. 63, fig. 7, pl. 157, fig. 2.
Krammer & Lange-Bertalot 1986, p. 116, fig. 38: 10-15.
Patrick & Reimer 1966, p. 467, pl. 44, fig. 6.
Common varieties: None
Similar species: Craticula accomoda (p. 30)
Craticula halophila (p. 31)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be moderately abundant.
Preference for high nutrient waters. Recorded in both
epipelic and epilithic assemblages.
Fig. 76. Navicula gregaria: (a-d) Barwon River, VIC, x2300.

92
Navicula cf. heimansioides
Lange-Bertalot 1993 (Figs 77a-d)
Synonyms: None
Description: Valve linear-lanceolate, with broadly rounded ends. Axial area narrow. Raphe filiform and
with proximal and distal ends deflected to the same side. The distal ends are terminated with a distinct
"hook-shape". The central area is lanceolate to slightly rounded, and is formed by alternately shorter and
longer striae. The striae are strongly radial in the central region tending to strongly convergent distally.
Punctae are not visible. Length 40-57 µm, width 6-6.5 µm, striae density 12-14/10 µm.
Key references: Krammer & Lange-Bertalot 1991, p. 388, fig. 70: 1-8 (no description).
Common varieties: None
Similar species: Navicula cryptocephala (p. 88)
Navicula cryptotenella (p. 89)
Navicula radiosa var. parva Wallace 1960 (sensu Holland & Clark, 1989)
(Not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 77. Navicula heimansioides: (a) Victoria
River, VIC, x1600; (b) Kiewa River, VIC,
x1500.
Notes: There is currently some debate as to the correct
identification of this species in Australian waters. We
feel that the specimens that we encounter are most
similar to N. heimansioides shown in Krammer and
Lange-Bertalot (1991). Most commonly found in both
epipelic and epilithic assemblages.

93
Navicula incertata
Lange-Bertalot 1985 (Figs 78a-c)
Synonyms: Navicula incerta Grunow in Van Heurck 1880
Description: Valve linear-lanceolate with sharpely rounded ends. Axial area distinct, narrowly lanceolate in
the centre, raphe filiform. Central area absent, or slightly transverse. Striae parallel to slightly radial
becoming convergent at the valve ends. Striae lightly lineolate, not usually seen under LM. Length 12-17.5
(7-20) µm, width 2.5-4.5 (2.5-4.5) µm, striae density 14-16 (13-16)/10 µm.
Key references: Krammer & Lange-Bertalot 1986, p. 111, fig. 35: 21-24.
Common varieties: None
Similar species: Navicula bremensis (not described in this guide)
Navicula perminuta (not des cribed in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 78. Navicula incertata: (a) Salt Creek,
SA, x1750; (b) Tyrrell Creek, VIC, x1750;
(c) Broughton River, SA, x1750.
Notes: Widespread though rarely abundant. Can be an
indicator of saline conditions. Found in epipelic and
epilithic assemblages.
Navicula lanceolata
(Agardh) Kützing 1844 (Figs 79a-c)
Synonyms: Frustulia lanceolata Agardh 1827
Navicula avenacea (Brébisson) Grunow in Schneider 1878
Schizonema thwaitesii Grunow in Van Heurck 1880
Description: Valve lanceolate, with either acutely or broadly rounded ends. Axial area narrow. Central area
broadly circular, formed by several shortened striae. Striae radial, becoming convergent distally. Striae
density slightly less in central area. The valve shape can vary between populations, with some specimens
exhibiting broadly lanceolate valves. Length 48-60 (28-70) µm, width 10-10.5 (8-12) µm, striae density 10-
12 (10-13)/10 µm.
Key references: Germain 1981, p. 180, pl. 68.
Holland & Clark 1989, p. 20, pl. 16, fig. 7.
Krammer & Lange-Bertalot 1986, p. 100, fig. 29: 5-7.
Patrick & Reimer 1966, p. 511, pl. 48, figs 19-20.

94
Navicula lanceolata cont.
Common varieties: None
Similar species: Navicula cryptocephala (p. 88)
Navicula radiosa (p. 96)
Navicula viridula (p. 101)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 79. Navicula lanceolata: (a) Dandenong
Creek, VIC, x1750; (b) River Torrens, SA,
x1750; (c) Olinda Creek, VIC, x1750.
Notes: Widespread though rarely abundant. More
common in lowland areas. Poor indicator of EC and
nutrient conditions. Found in epipelic and epilithic
assemblages.
Navicula menisculus
Schumann 1867 (Fig. 80)
Synonyms: Refer to individual variety descriptions.
Description: Valve broadly lanceolate, elliptical-lanceolate with acutely rounded to sub-rostrate ends. Axial
area narrow, linear, occasionally slightly widened at the central area, raphe filiform. Central area transverse,
shape varying between lanceolate, rectangular to circular. Central area with variously shortened medial striae
on either side. Striae weakly to strongly radial in the central area, either remaining radial, or becoming
parallel to convergent at the valve ends. Striae finely lineolate. Length 16 (15-50) µm, width 5.5 (7.5-12)
µm, striae density 16 (8-12)/10 µm.
Key references: Germain 1981, p. 186, pl. 71, fig. 6.
Krammer & Lange-Bertalot 1986, p. 105, fig. 32: 16-25.
Common varieties:
var. menisculus
Nominate variety, description as above.

95
Navicula menisculus cont.
var. upsaliensis Grunow in Cleve & Grunow 1880
Syn: Navicula upsaliensis (Grunow) Peragallo 1903
Distal striae parallel or convergent, not radial as in the nominate variety (Patrick & Reimer, 1966).
Similar species: Navicula cryptotenella (p. 89)
Navicula veneta (p. 101)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread though rarely abundant. Reliable
indicator of saline conditions. More common in
lowland and foothill areas. Found in epipelic and
epilithic assemblages.
Fig. 80. Navicula menisculus, Wimmera River, VIC,
x1750.
Navicula molestiformis
Hustedt 1949 (Figs 81a-b)
Synonyms: Navicula fluens Hustedt 1930
Navicula twymaniana Archibald 1966
Navicula hariola Cholnoky 1966
Description: Valve lanceolate to elliptic-lanceolate, with slightly elongated, broadly rounded ends. Axial
area narrow and linear. Raphe filiform. Central area absent. Striae parallel to weakly radial, less densely
spaced in the central region than at the ends (often not discernable under LM). Length 9-14 (9.5-22) µm,
width 3-4 (3-5) µm, striae density 28-38 (23-36)/10 µm.
Key references: Archibald 1983, p. 222.
Germain 1981, p. 228, pl. 85, fig. 14.
Krammer & Lange-Bertalot 1986, p. 130, fig. 45: 1-9.
Common varieties: None
Similar species: Craticula accomoda (p. 30)
Craticula halophila (p. 31)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread in high nutrient waters but not
usually abundant. Recorded in both epipelic and
epilithic assemblages. The validity of Navicula
molestiformis within the genus Navicula has been
subject to recent investigation, and it is now considered
to belong to the genus Craticula (Lange-Bertalot, in
press).
Fig. 81. Navicula molestiformis, (a-b) Dandenong Creek, VIC, x2800.

96
Navicula radiosa
Kützing 1844 (Figs 82a-b)
Synonyms: Refer to individual variety descriptions.
Description: Valve linear-lanceolate to lanceolate, with drawn out, sharp, rounded ends. Axial area narrow
and linear, raphe filiform. Central area weakly transverse, rhomboid. Striae radial throughout the valve,
tending to convergent at the ends. Length 54.5-100 (40-120) µm, width 10-12 (10-15) µm, striae density 9-
11 (10-12)/10 µm.
Key references: Foged 1978, p. 97, pl. 29, figs 10, 11.
Krammer & Lange-Bertalot, 1986, p. 99, fig. 29: 1-4.
Patrick & Reimer 1966, p. 509, pl. 48, fig. 15.
Thomas 1983, p. 55, pl. 7, fig. 21.
Vyverman et al. 1995, p. 70.
Common varieties:
var. radiosa
Syn: Pinnularia radiosa (Kützing) Rabenhorst 1853
Navicula radiosa var. acuta (W. Smith) Grunow 1860
Nominate variety, refer to description above.
var. parva Wallace 1960
Valve smaller in size and with denser striae.
Similar species: Navicula cryptocephala (p. 88)
Navicula cryptotenella (p. 89)
Navicula heimansioides (p. 92)
Navicula gondwana Lange-Bertalot 1996 (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 82. Navicula radiosa: (a) Latrobe River,
VIC, x1050; (b) Snowy River, VIC, x950.
Notes: Widespread and moderately abundant. A
polymorphic taxon, and so taxonomic confusion may
arise. Most commonly recorded in epipelic and
epilithic assemblages.

97
Navicula recens
(Lange-Bertalot) Lange-Bertalot 1985 (Fig. 83)
Synonyms: Navicula cari var. recens Lange-Bertalot 1980
Description: Valve linear-lanceolate to elliptical-lanceolate, with sharply rounded ends. Axial area narrow
and linear. Raphe filiform and straight. Central area large, often one-sided, rectangular to rhomboid, almost
reaching half the valve width. Striae surrounding the central area alternately shorter and longer. Striae
moderately radial in the central region, becoming parallel to convergent distally. Striae finely lineolate, not
usually seen under LM. Length 22 (16-40) µm, width 7 (6.5-9) µm, striae density 13 (11-14)/10 µm.
Key references: Krammer & Lange-Bertalot 1986, p. 95, fig. 27: 7-11.
Common varieties: None
Similar species: Navicula erifuga (p. 90)
Navicula lanceolata (p. 93)
Navicula menisculus (p. 94)
Ecological preferences:
TP
EC
pH
12 3 4 5
Notes: Widespread but rarely abundant. Preference for
brackish streams. Found in epipelic and epilithic
assemblages.
Fig. 83. Navicula recens, Scott River, WA, x1750.
Navicula rhynchocephala
Kützing 1844 (Figs 84a-b)
Synonyms: Refer to individual variety descriptions.
Description: Valve lanceolate with elongated rostrate to capitate ends. Axial area narrow. Central area
transversely widened to circular, with the proximal raphe ends offset to one side of the central area. Striae in
the central region of the valve radiate and widely spaced, whereas striae at the valve ends convergent and
more densely spaced. The striae conspicuously punctate 20-25/10 µm (may be easily seen at x400
magnification). Length 54-56 (35-80) µm, width 10 (9-14) µm, striae density 8-10 (7-12)/10 µm.
Key references: Germain 1981, p. 180, pl. 69, figs 1-6.
Holland & Clark 1989, p. 21, pl. 16, fig. 12.
Krammer & Lange-Bertalot 1986, p. 101, figs 30: 5-8, 31: 1, 2.
Patrick & Reimer 1966, p. 505, pl. 48, fig. 6.
Thomas 1983, p. 55, pl. 7, fig. 20.
Common varieties:
var. rhynchocephala
Nominate variety, description as above.

98
Navicula rhynchocephala cont.
var. amphiceros (Kützing) Grunow in Cleve & Grunow 1880
Syn: Navicula amphiceros Kützing 1844
Valve broader, ends of valve less elongate, not capitate (Patrick & Reimer, 1966).
Similar species: Navicula cryptocephala (p. 88)
Navicula rhynchotenella Lange-Bertalot 1996 (not described in this guide)
Navicula viridula (p. 101)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 84. Navicula rhycocephala: (a-b)
Blackwood River, WA, x1750.
Notes: Widespread but not usually abundant.
Recorded in both epipelic and epilithic assemblages.
Navicula salinarum
(Grunow) in Cleve & Grunow 1880 (Figs 85a-c)
Synonyms: None
Description: Valve linear-lanceolate to linear elliptical, with acutely narrowed, drawn out ends that are
rostrate to capitate. Axial area narrow and linear. Raphe straight and filiform, slightly arcuate in some
specimens. Central area prominent, circular/elliptical to lanceolate, with more widely spaced, alternately
shorter and longer striae on either side (approx. 4-7 striae). Striae strongly radial, becoming parallel to
convergent at the valve ends. Length 20-36 (20-40) µm, width 6.5-11 (8-12) µm, striae density 14-16 (13-
17)/10 µm.
Key references: Foged 1978, p. 98, pl. 30, fig. 9.
Germain 1981, p. 189, pl. 72, figs 12, 13.
John 1983, p. 99, pl. 42, figs 1, 2.
Krammer & Lange-Bertalot 1986, p. 110, fig. 35: 5-8.
Patrick & Reimer 1966, p. 502, pl. 48, fig. 1.

99
Navicula salinarum cont.
Common varieties: None
Similar species: Navicula cryptocephala (p. 88)
Navicula lanceolata (p. 93)
Navicula viridula (p. 101)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 85. Navicula salinarum: (a-c)
Blackwood River, WA, x1750.
Notes: Widespread but not usually abundant. Found in
epipelic and epilithic assemblages. Good indicator of
nutrient enriched, high conductivity waters.
Navicula schroeterii
Meister 1932 (Figs 86a-c)
Synonyms: Navicula simulata Manguin 1942
Navicula schroeterii var. escambia Patrick 1959
Description: Valve linear-lanceolate to linear-elliptical with broadly rounded ends. Axial area narrow,
slightly arcuate. Raphe filiform, proximal ends turned in the same direction. Central area large, circular to
rectangular, and asymmetrical (always more pronounced on one side). Transapical striae continuously radial
to the ends, distinctly lineolate. Lineolae often forming longitudinal lines. Length 31-42 (30-55) µm, width
7-8 (5-9) µm, striae density 12 (12-16)/10 µm, lineolae density (20 -28)/10 µm.
Key references: Foged 1978, p. 99, pl. 30, fig. 13.
Germain 1981, p. 195, pl. 74, figs 1-6.
Holland & Clark 1989, p. 21, pl. 16, fig. 9.
John 1983, p. 100, pl. 42, fig. 3.
Krammer & Lange-Bertalot 1986, p. 115, fig. 38: 1-4.
Patrick & Reimer 1966, p. 512, pl. 49, fig. 1.
Common varieties: None
Similar species: Navicula erifuga (p. 90)
Navicula recens (p. 97)
Navicula symmetricaPatrick 1944 (not described in this guide)

100
Navicula schroeterii cont.
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 86. Navicula schroeterii: (a-b) Bremer
River, SA, x1750; (c) Jacksons Creek, VIC,
x1750.
Notes: Widespread but not usually abundant. Not
commonly encountered in freshwaters. Recorded in
epipelic and epilithic assemblages.
Navicula tenelloides
Hustedt 1937 (Figs 87a-e)
Synonyms: None
Description: Valve narrow, linear-lanceolate, with broadly rounded sub-rostrate ends. Axial area narrow
and linear, raphe straight and filiform. Central area very small, circular to rectangular, varying with the
number of shortened striae on either side of the central area. Striae in the centre strongly radial becoming
weakly convergent at the valve ends. Striae finely lineolate, lineolae rarely visible under LM. Length 16-20
(14-21) µm, width 3-3.5 (2.5-4) µm, striae density 19-20 (15-17)/10 µm.
Key references: Krammer & Lange-Bertalot 1986, p. 117, fig. 38: 16-20.
Patrick & Reimer 1966, p. 534, pl. 51, fig. 7.
Common varieties: None
Similar species: Navicula cryptocephala (p. 88)
Navicula cryptotenella (p. 89)
Navicula veneta (p. 101)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but not usually abundant.
Recorded in a wide range of nutrient concentrations.
Found in epipelic and epilithic assemblages.
Fig. 87. Navicula tenelloides: (a) Adelong River,
NSW, x1750; (b) Wimmera River, VIC, x1750.

101
Navicula veneta
Kützing 1844 (Figs 88a-e)
Synonyms: Navicula cryptocephala var. veneta (Kützing) Rabenhorst 1864
Navicula cryptocephala var. subsalina Hustedt 1925
Description: Valve linear-lanceolate to rhomboid-lanceolate, with slightly drawn out, rounded ends. Axial
area narrow and straight, raphe filiform and with prominent proximal ends. Central area transverse,
rectangular to almost fasciculate, formed by several variously shortened medial striae. Striae radial in the
central region, becoming convergent at the valve ends. Striae finely lineolate but usually indistinct. Length
19-22 (13-30) µm, width 4.5-5 (5-6) µm, striae density 14 (13.5-15)/10 µm.
Key references: Krammer & Lange-Bertalot 1986, p. 104, fig. 32: 1-4.
Patrick & Reimer 1966, p. 504, pl. 48, fig. 5.
Common varieties: None
Similar species: Navicula cryptocephala (p. 88)
Navicula gregaria (p. 91)
Navicula incertata (p. 93)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 88. Navicula veneta: (a-b) Wimmera
River, VIC, x1750; (b) Wannon River, VIC,
x1750; (d) Dawesley Creek, SA, x1750; (e)
Blackwood River, WA, x1750.
Notes: Widespread and can be moderately abundant.
More common in lowland environments. Poor
indicator of environmental conditions. Recorded in
both epipelic and epilithic assemblages.
Navicula viridula
(Kützing) Ehrenberg 1838 (Figs 89a-d)
Synonyms: Refer to individual variety descriptions.
Description: Valve lanceolate to linear-lanceolate, with drawn out, rostrate to sub-capitate ends. Axial area
narrow, linear. Raphe straight with proximal ends noticeably deflected to one side. Central area variable,
from circular to distinctly one-sided (one side much more pronounced). Medial striae variously shortened,
generally reaching no more than half way between margin and central node. Striae coarsely lineolate
(lineolae visible under LM). Striae in the central region widely spaced and strongly radial, becoming parallel
to convergent at the valve ends. Length 42-43 (34-100) µm, width 9 (7-15) µm, striae density13-14 (7-14)/10
µm, lineolae density (24-30)/10 µm

102
Navicula viridula cont.
Key references: Germain 1981, p. 178, pl. 67, figs 1-5.
Holland & Clark 1989, p. 21, pl. 16, fig. 1.
John 1983, p. 99, pl. 41, figs 11, 12.
Krammer & Lange-Bertalot 1986, p. 114, fig. 37: 1-9.
Patrick & Reimer 1966, p. 506, pl. 48, fig. 8, p. 507, pl. 48, fig. 12.
Thomas 1983, p. 56, pl. 7, fig. 12.
Common varieties:
var. viridula
Syn: Frustulia silesiaca Bleisch ex Fresenius 1862
Not commonly found in Australian streams.
var. germainii (Wallace) Lange-Bertalot
Syn: Navicula germainii Wallace 1960
Navicula rhynchocephala var. germainii (Wallace) Patrick 1966
Valve broadly lanceolate, sub-capitate-rostrate ends. Distinguished in part on shape and finer density of
striae. Length 36 (34-100) µm, width 8 (7-15) µm, striae density 12 (7-14)/10 µm.
var. rostellata (Kützing) Cleve 1895
Syn: Navicula rostellata Kützing 1844
Navicula rhynchocephala var. rostellata (Kützing) Grunow in Cleve & Grunow 1880
Valve linear-lanceolate with drawn out, rostrate to sub-capitate ends. Central area rounded. Striae
strongly radial becoming convergent at the valve ends. Distinguished on the drawn out shape of the
valve ends and the distinctive angular curvature of the valve margins distally. Length (34-50) µm, width
(7-10) µm, striae density (11-14)/10 µm.
Similar species: Navicula cryptocephala (p. 88)
Navicula lanceolata (p. 93)
Navicula rhyncocephala (p. 97)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 89. Navicula viridula: (a) var. viridula,
Valencia Creek, VIC, x1750; (b-c) var.
rostellata; (b) Deep Creek, VIC, x1750; (c)
Ovens River, VIC, x1750; (d) var. germanii,
Blackwood River, WA, x1750.
Notes: Widespread, particularly in foothills and
lowland areas, moderately abundant. Found in epipelic
and epilithic assemblages.

103
Genus Nitzschia
Key to the common species
1a. Frustules sigmoidally curved in either valve or girdle view .................................................................. 2
1b. Valve apppearing otherwise ................................................................................................................. 4
2a. Valve with central node ....................................................................................................................... 3
2b. Valve without central node ........................................................................................... Nitzschia sigma
3a. Valve ends sub-capitate to capitate, laterally bent to the opposite side .......................... Nitzschia clausii
3b. Valve linear to linear-lanceolate, ends sometimes broadly rounded (some of the larger forms appearing
linear, sigmoid curvature sometime difficult to determine) ...................................... Nitzschia filiformis
4a. Raphe located on the valve face but away from the valve margin ............................. Nitzschia dissipata
4b Valve appearing otherwise ................................................................................................................... 5
5a Valve with central node ....................................................................................................................... 6
5b. Valve without central node ................................................................................................................ 13
WITH NODE
6a. Fibulae narrow, wedge-shaped ‘tooth-like’. Fibulae usually united with only one striae ....................... 7
6b. Fibulae wider, each fibulae united with more than one striae ................................................................ 8
7a. Striae coarse, < 20/10 µm, noticeably punctate, ...................................................... Nitzschia amphibia
7b. Striae dense, 28-41/10 µm ......................................................................................... Nitzschia linearis
8a. Striae mostly distinguishable as punctate ............................................................................................. 9
8b. Striae appearing otherwise ................................................................................................................. 10
9a. Valve short, 3-22 µm, elliptical to linear-elliptical, ends bluntly rounded ........... .Nitzschia inconspicua
9b. Valves longer, linear-linear lanceolate, ends sharply rounded ....................... Nitzschia frustulum (part)
10a. Valve broadly linear .............................................................................................. Nitzschia umbonata
10b. Valve linear-lanceolate ...................................................................................................................... 11
11a. Valve ends sub-capitate to capitate .................................................................................................... 12
11b. Valve ends acutely rounded, sometimes tending sub-capitate ....................... Nitzschia frustulum (part)
12a. Fibulae irregularly spaced, 7-13/10 µm ..................................................................... Nitzschia tubicola
12b. Fibulae regularly spaced, 10-18/10 µm .................................................................. Nitzschia capitellata
WITHOUT NODE
13a. Fibulae narrow, wedge-shaped, each fibulae usually united with only one striae ............ Nitzschia recta
13b. Fibulae wider, each fibulae united with more than one striae .............................................................. 14
14a. Valves linear, elongate, always > 30 µm ............................................................................................ 15
14b. Valves appearing otherwise ............................................................................................................... 17
15a. Valve ends distinctly drawn tending to rostrate, striae not visible under LM ....................................... 16
15b. Valves appearing otherwise ................................................................................ Nitzschia palea (part)
16a. Valve ends clearly spiculate ................................................................................... Nitzschia acicularis
16b. Valve appearing otherwise ......................................................................................... Nitzschia gracilis
17a. Valve short, linear to linear-lanceolate < 20 µm, clearly capitate ends ............... Nitzschia microcephala
17b. Valve appearing otherwise ................................................................................................................. 18

104
18a. Striae density less than 35/10 µm ....................................................................................................... 19
18b. Striae greater than 35/10 µm, frequently not visible ........................................................................... 22
19a. Valve linear-lanceolate, narrowing abruptly to sub-capitate ends ........................ .Nitzschia desertorum
19b. Valve appearing otherwise ................................................................................................................. 20
20a. Valve linear, sub-capitate ends ............................................................................. .Nitzschia perminuta
20b. Valve appearing otherwise ................................................................................................................. 21
21a. Fibulae irregularly spaced, striae density > 28/10 mm .......................................... Nitzschia palea (part)
21b. Fibulae regularly spaced, striae density 19-30/10 mm ............................................ Nitzschia liebetruthii
22a. Valves with bluntly rounded ends, not or only slightly drawn .................................. Nitzschia aurariae
22b. Valves appearing otherwise ............................................................................................................... 23
23a. Valves > 20 mm long ................................................................................................... Nitzschia agnita
23b. Valves shorter ........................................................................................................... Nitzschia lacuum
Nitzschia acicularis
(Kützing) W. Smith 1853 (Fig. 90)
Synonyms: Synedra acicularis Kützing 1844
Description: Valve linear-lanceolate with prominent, elongated, narrow ends, the valve thus appearing
spindle-shaped. Raphe canal marginal, fibulae small. Central nodule absent. Striae extremely delicate and
dense, indistinguishable by LM. Valve weakly silicified, cell walls often just visible by LM. Length 52
(30-150) µm, width 3.5 (2.2-5) µm, fibulae density 17 (15-22)/10 µm.
Key references: Krammer & Lange-Bertalot 1988, p. 123, fig. 85: 1-4.
Common varieties: None
Similar species: Nitzschia draveillensis (similar to N. acicularis but with a node, not described in this guide)
Nitzschia gracilis (p. 113)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be moderately abundant.
Mostly a planktonic taxon although can also inhabit
the benthos.
Fig. 90. Nitzschia acicularis, Adelong River, NSW, x1750.

105
Nitzschia agnita
Hustedt 1957 (Fig. 91)
Synonyms: Nitzschia kuetzingioides Hustedt 1959
Nitzschia capensis Cholnoky 1959
Nitzschia irremissa Cholnoky 1959
Description: Valve lanceolate, acutely tapered, with small capitate ends. Raphe canal marginal, fibulae
small. Central nodule absent. Transapical striae extremely fine, greater than 35/10µm, therefore rarely visible
under the LM. Length 27-41 (18-40) µm, width 3.5-4.5 (2.9-4.6) µm, fibulae density 15-16 (13-20)/10 µm.
Key references: Archibald 1983, p. 232, figs 356-358.
Krammer & Lange-Bertalot 1988, p. 117, fig. 82: 9-11.
Common varieties: None
Similar species: Nitzschia gracilis (p. 113)
Nitzschia lacuum (p. 115)
Nitzschia palea (p. 119)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be moderately abundant.
Appears to be more common in lowland areas.
Recorded in both epipelic and epilithic assemblages.
Fig. 91. Nitzschia agnita, Bremer River, SA, x1750.
Nitzschia amphibia
Grunow 1862 (Figs 92a-b)
Synonyms: None
Description: Valve linear-lanceolate to lanceolate with short, pointed, sub-rostrate to rostrate ends. Raphe
canal marginal, fibulae very narrow, wedge-shaped, usually combined with only one stria. Central nodule
present. Striae coarsely punctate and parallel. Length 18-24 (6-50) µm, width 4-5 (4-6) µm, fibulae density 8
(7-9)/10 µm, striae density 16-18 (13-18)/10 µm.
Key references: Germain 1981, p. 358, pl. 135, figs 32-37.
Jensen 1985, p. 867, fig. 793.
John 1983, p. 165, pl. 72, fig. 14.
Krammer & Lange-Bertalot 1988, p. 108, fig. 78: 13-26.
Common varieties: None
Similar species: None

106
Nitzschia amphibia cont.
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread, particularly in lowland areas,
and can be moderately abundant. Found in
epipelic and epilithic assemblages.
Fig. 92. Nitzschia amphibia: (a) Lodddon River,
VIC, x1750; (b) Donnelly River, WA, x1750.
Nitzschia aurariae
Cholnoky 1966 (Figs 93a-b)
Synonyms: Nitzschia elliptica var. alexandrina Cholnoky 1958
Nitzschia alexandrina (Cholnoky) Lange-Bertalot & Simonsen 1978
Description: Valve linear-elliptical with broadly rounded ends. Raphe canal marginal. Fibulae very small,
and without a central nodule. Striae not visible under LM. Length 14 (6.5-18) µm, width 3-3.5 (2.5-3.5) µm,
fibulae density 16 (15-18)/10 µm, striae density > 48/10 µm.
Key references: Krammer & Lange-Bertalot 1988, p. 113, fig. 80: 16-21.
Lange-Bertalot & Simonsen 1978, p. 16, figs 196, 197, 285, 286.
Common varieties: None
Similar species: Nitzschia pusilla complex (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 93. Nitzschia aurariae: (a) Rocky Valley
Creek, SA, x1750; (b) Bremer River, SA,
x1750.
Notes: Widespread but not usually abundant except at
sites with elevated conductivities. Recorded in both
epipelic and epilithic assemblages.

107
Nitzschia capitellata
Hustedt in A. Schmidt et al. 1922 (Figs 94a-f)
Synonyms: Nitzschia subcapitella Hustedt 1939
Nitzschia balcanica Hustedt 1945
Nitzschia deserta Hustedt 1949
Nitzschia salincola Aleem & Hustedt 1951
Nitzschia frequens Hustedt 1957
Nitzschia manca Hustedt 1959
Nitzschia allansonii Cholnoky 1958
Nitzschia subfrequens Simonsen 1960
Description: Valve linear-lanceolate, with elongate, tapering, capitate ends. The central region of the valve
margins is weakly concave. Raphe canal marginal, fibulae small and with a central nodule. Transapical striae
fine and parallel, sometimes not easily distinguishable under LM. Length 33-54 (20-70) µm, width 4-5.5
(3.5-6.5) µm, fibulae density 10-15 (10-18)/10 µm, striae density 24 (23-40)/10 µm.
Key references: Germain 1981, p. 360, pl. 137, figs 1-4.
Krammer & Lange-Bertalot 1988, p. 88, figs 62: 1-12, 63: 1-3, 14.
Common varieties: None
Similar species: Nitzschia intermedia Hantzsch ex Cleve & Grunow 1880 (not described in this guide)
Nitzschia palea (p. 119)
Nitzschia tubicola (p. 123)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 94. Nitzschia capitellata: (a-c)
Dawesley Creek, SA. x1750; (d)
Dandenong Creek, VIC, x1750; (e)
Dawesley Creek, SA, x1750; (f) Collie
River, WA, x1750; (g) Bremer River, SA,
x1750.
Notes: Widespread and can be very abundant,
particularly in lowland areas. This taxon has been
recorded in streams affected by acid mine drainage, heavy
metal contamination and nutrient enrichment. Recorded in
both epipelic and epilithic assemblages.

108
Nitzschia clausii
Hantzsch 1860 (Figs 95a-b)
Synonyms: Nitzschia sigma var. clausii (Hantzsch) Grunow 1878
Nitzschia sigma var. curvata (Ehrenberg) Brun 1880
Description: Valve sigmoid in valve view. Valve margins linear with short, sharply tapered, capitate ends.
Raphe canal marginal with a pronounced central nodule present. Fibulae small and irregularly spaced, and.
Striae extremely fine and parallel, just visible under LM. Length 35-43 (20-55) µm, width 3-3.5 (3-5) µm,
fibulae density 10-13 (10-13)/10 µm, striae density > 35/10 µm.
Key references: Germain 1981, p. 368, pl. 139, figs 7-9.
Krammer & Lange-Bertalot 1988, p. 31, fig. 19: 1-6A.
Common varieties: None
Similar species: Nitzschia filiformis var. conferta (p. 111)
Nitzschia obtusa W. Smith 1853 (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 95. Nitzschia clausii: (a-b) Ovens
River, VIC, x1750.
Notes: Widespread but not usually abundant. More
common in lowland areas. Recorded in both epipelic and
epilithic assemblages.

109
Nitzschia desertorum
Hustedt 1949 (Figs 96a-c)
Synonyms: None
Description: Valve broadly linear to linear-lanceolate with sharply rounded, subcapitate to capitate ends.
Raphe canal marginal. Fibulae small, more widely spaced in the centre than at the ends. Striae finely
punctate, parallel in the centre, becoming radial towards the valve ends. Length 20-23 (17-20) µm, width 3.5-
4 (4-5) µm, fibulae density 12-13 (10-15)/10 µm, striae density 21-24 (25)/10 µm.
Key references: Krammer & Lange-Bertalot 1988, p. 98, fig. 70: 10-13.
Common varieties: None
Similar species: Nitzschia hantzschiana Rabenhorst 1860 (not described in this guide)
Nitzschia palea (p. 119)
Nitzschia solita Hustedt 1953 (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 96. Nitzschia desertorum: (a) Dawesley
Creek, SA, x1750; (b) River Torrens, SA,
x1750; (c) Dawesley Creek, SA, x1750.
Notes: Widespread and can be abundant. More
common in lowland areas. Recorded in both epipelic
and epilithic assemblages. Found in fresh to brackish
waters of medium to high nutrient concentration.

110
Nitzschia dissipata
(Kützing) Grunow 1862 (Figs 97a-c)
Synonyms: Refer to individual variety descriptions.
Description: Valve linear to lanceolate, with bluntly rounded to rostrate to sub-capitate ends. Raphe canal
central toslightly eccentric, lacking central node. Fibulae conspicuous and irregularly spaced. Striae not
usually visible. Length 35-57 (12.5-85) µm, width 4-5.5 (3.5-7) µm, fibulae density 8 (5-11)/10 µm, striae
density > 30/10 µm.
Key references: Germain 1981, p. 344, pl. 130, figs 1-10.
Holland & Clark 1989, p. 22, pl. 18, fig. 2.
John 1983, p. 167, pl. 69, figs, 6, 7.
Krammer & Lange-Bertalot 1988, p. 19, fig. 11: 1-14.
Common varieties:
var. dissipata
Syn: Synedra dissipata Kützing 1844
Nominate variety, refer to description above.
var. media (Hantzsch) Grunow 1881
Syn: Nitzschia media Hantzsch 1863
Raphe canal more eccentric.
Similar species: Nitzschia recta (p. 121).
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 97. Nitzschia dissipata: (a) Ovens River,
VIC, x1750; (b) Yackandandah Creek, VIC,
x1750; (c) Deep Creek, VIC, x1750.
Notes: Widespread but not usually abundant This
species is generally easily identified by the central to
slightly eccentric position of the raphe canal and the
conspicuous "ladder" arrangement of the fibulae. Most
commonly recorded in epipelic and epilithic
assemblages, although occasionally planktonic.

111
Nitzschia filiformis
(W. Smith) Van Heurck 1896 (Figs 98a-d)
Synonyms: Refer to individual variety descriptions.
Description: Valve weakly sigmoid in girdle view. In valve view, slightly sigmoid, linear to linear-
lanceolate, with broadly rounded ends. Raphe canal marginal with a distinct central nodule and weakly
retracted in the centre. Fibulae prominent, more or less regularly spaced. Striae highly dense, sometimes
difficult to see under LM. Length 63-78 (20-100) µm, width 4.5-5 (4-6) µm, fibulae density 7-8
(7-11)/10 µm, striae density 32 (27-36)/10 µm.
Key references: Foged 1978, p. 105, pl.46, fig. 6.
Germain 1981, p. 372, pl. 140, figs 6-8.
Krammer & Lange-Bertalot 1988, p. 27, figs 19: 7-13, 20: 1-7, 13, 14.
Common varieties:
var. filiformis
Syn: Homoeocladia filiformis W. Smith 1856
Homoeocladia germanica Richter 1879
Nominate variety, description as above.
var. conferta (Richter) Lange-Bertalot 1987
Syn: Homoeocladia conferta Richter 1879
Nitzschia conferta (Richter) M. Peragallo 1903
Nitzschia accedens Hustedt 1939
Valve ends acutely rounded (Krammer & Lange-Bertalot, 1988).
Similar species: Nitzschia fasciculata (Grunow) Grunow in Van Heurck 1881 (not described in this guide)
Nitzschia palea (p. 119)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and frequently abundant. N.
filiformis is often found growing in mucilaginous
tubes. Found in epipelic and epilithic assemblages.
Fig. 98. Nitzschia filiformis: (a-b) var. conferta; Dandenong Creek, VIC, x1750; (c-d) var. filiformis; (c)
Loddon River, VIC, x1750; (d) Torrens River, SA, x1750.

112
Nitzschia frustulum
(Kützing) Grunow in Cleve & Grunow 1880 (Figs 99a-d)
Synonyms: Synedra frustulum Kützing 1844
Synedra minutissima Kützing 1844
Synedra perpusilla Kützing 1844
Synedra quadrangula Kützing 1844
Nitzschia minutissima W. Smith 1853
Homoeocladia bulnheimiana Rabenhorst 1864
Nitzschia liebetruthii var. siamensis Hustedt 1922
Nitzschia quadrangula Krammer 1998
Description: Valve quite variable in shape, from lanceolate, linear-lanceolate to almost elliptical, sometimes
slightly concave centrally, with either sharply rounded or drawn out, subcapitate ends. Elliptic forms with
more bluntly rounded ends. Raphe canal marginal. The two central fibulae distinctly separated to form a
central nodule (not always obvious under LM). Transapical striae finely punctate and parallel. Length 15-20
(5-60) µm, width 2.5-3 (2-4.5) µm, fibulae density 9-12 (10-16)/10 µm, striae density 22-29 (19-30)/10 µm.
Key references: Foged 1978, p. 105, pl. 46, fig. 18.
Germain 1981, p. 352, pl. 133, figs 6-12.
Holland & Clark 1989, p. 22, p l. 17, fig. 7.
Krammer & Lange-Bertalot 1988, p. 94, fig. 68: 1-19.
Lange-Bertalot & Simonsen 1978, p. 23, figs 1-39, 292, 293.
Common varieties: Although several of varieties of N. frustulum have been described, it is very difficult to
distinguish between them considering the large range of morphological variation that is
observed in this species
Similar species: Nitzschia acidoclinata Lange-Bertalot 1988 (not described in this guide)
Nitzschia inconspicua (once a variety of N. frustulum) (p. 114)
Nitzschia liebetruthii (p. 116)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be very abundant.
Common in polluted waters. Recorded in epipelic and
epilithic assemblages.
Fig. 99. Nitzschia frustulum: (a) Hopkins River, VIC, x1750, (b-c) Dawesley Creek, SA, x1750; (d) East
Tanjil River, VIC, x1750.

113
Nitzschia gracilis
Hantzsch 1860 (Figs 100a-c)
Synonyms: Nitzschia graciloides Hustedt 1953
Description: Valve elongate, narrowly linear-lanceolate, with elongate, gradually tapered, sub-capitate to
capitate ends. Raphe canal marginal, fibulae very small. Central nodule absent. Transapical striae extremely
fine, almost indistinguishable under LM. Length 55 (30-110) µm, width 2.5 (2.5-4) µm, fibulae density 13
(12-18)/10 µm, striae density /10 µm.
Key references: Germain 1981, p. 348, pl. 131, figs 6-11.
Krammer & Lange-Bertalot 1988, p. 93, fig. 66: 1-11.
Common varieties: None
Similar species: Nitzschia graciliformis Lange-Bertalot & Simonsen 1978 (not described in this guide)
Nitzschia palea (p. 119)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 100. Nitzschia gracilis: (a) Ovens River,
VIC, x1750; (b) Mooki River, NSW, x1750;
(c) Deep Creek, VIC, x1750.
Notes: Widespread, particularly in foothills and
upland areas but with relatively low abundance. Most
commonly recorded in epipelic and epilithic
assemblages, although can occasionally be planktonic.

114
Nitzschia inconspicua
Grunow 1862 (Figs 101a-b)
Synonyms: Synedra perpusilla Kützing 1844
Nitzschia frustulum var. inconspicua Grunow in Van Heurck 1881
Nitzschia perpusilla Grunow 1862
Nitzschia invisitata Hustedt 1949
Description: Valve short, elliptical to linear-lanceolate with bluntly rounded ends. Raphe canal marginal.
Fibulae distinct, somewhat irregularly spaced on smaller valves. Two central fibulae widely spaced forming
a central nodule that is not conspicuous in some valves. Striae tend to appear punctate under LM, parallel in
the centre becoming weakly radial at the very ends. Length 7-12 (3-22) µm, width 2.5-3 (2.5-3.5) µm,
fibulae density 13 (8-13)/10 µm, striae density 27 (23-32)/10 µm.
Key references: Germain 1981, p. 356, pl. 134, figs 23-26.
Krammer & Lange-Bertalot 1988, p. 95, fig. 69: 1-13.
Common varieties: None
Similar species: Nitzschia abbreviata Hustedt in A. Schmidt et al. 1924 (not described in this guide)
Nitzschia frustulum (p. 112)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be abundant. Appears to
be more common in upland areas. Nitzschia abbreviata
Nitzschia inconspicua and Nitzschia frustulum (Lange
Bertalot pers. comm.) appear to occur along a cline of
increasing salinity. Recorded in both epipelic and
epilithic assemblages.
Fig. 101. Nitzschia inconspicua: (a) Adelong River,
NSW, x1750; (b) Nitzschia cf. frustulum, Torrens
River, SA, x1750.

115
Nitzschia lacuum
Lange-Bertalot 1980 (Fig. 102)
Synonyms: None
Description: Valve relatively short, distinctly lanceolate, with acutely narrowed, capitate ends. Raphe canal
marginal, fibulae distinct. Central nodule absent. Striae closely spaced (> 35/10 µm), generally
indistinguishable under LM. Length 14 (10-20) µm, width 3.5 (2-3) µm, fibulae density 14 (13-18)/10 µm,
striae density (35-40)/10 µm.
Key references: Krammer & Lange-Bertalot 1988, p. 107, fig. 78: 1-6.
Common varieties: None
Similar species: Nitzschia agnita (p. 105)
Nitzschia bacillum Hustedt in A. Schmidt et al. 1922 (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be moderately abundant,
particularly with lowland areas. Recorded in both
epipelic and epilithic assemblages.
Fig. 102. Nitzschia lacuum, Mooki River, NSW,
x1750.

116
Nitzschia liebetruthii
Rabenhorst 1864 (Figs 103a-b)
Synonyms: Refer to individual variety descriptions.
Description: Valve narrowly linear-lanceolate to lanceolate, with drawn out, rounded to subcapitate ends.
Raphe canal marginal, fibulae small and without central nodule. Striae relatively widely spaced and finely
punctate. Length 22-32 µm, width 3 µm, fibulae density 10-12/10 µm, striae density 25-26/10 µm.
Key references: Krammer & Lange-Bertalot 1988, p. 96, fig. 69: 14-32.
Common varieties:
var. liebetruthii
Syn: Nitzschia perpusilla Grunow 1862 non Rabenhorst 1861
Nominate variety, refer to description above.
var. major Grunow in Cleve & Möller 1879
Valve length greater than 40 µm, striae density around 15/10 µm (Krammer & Lange-Bertalot, 1988).
Similar species: Nitzschia frustulum (p. 112)
Nitzschia supralitorea Lange-Bertalot 1979 (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 103. Nitzschia liebetruthii: (a) Ovens
River, VIC, x1750; (b) Murray River,
Mildura, VIC, x1750.
Notes: Widespread, low to moderate abundance. Poor
nutrient indicator. Recorded in both epipelic and
epilithic assemblages.

117
Nitzschia linearis
(Agardh) W. Smith 1853 (Figs 104a-b)
Synonyms: Refer to individual variety descriptions.
Description: Valve broadly linear with acutely drawn out sub-capitate to capitate ends. Raphe canal
marginal and prominent. Valve with a distinct central constriction on the raphid margin. Ends often deflected
away from raphe side. Fibulae conspicuous, long and irregular. The two central fibulae widely spaced
forming a central nodule. Striae fine and parallel. Length 70-132 (34-228) µm, width 4-6 (2.5-7.5) µm,
fibulae density 11-13 (8-17)/10 µm, striae density 32 (28-41)/10 µm.
Key references: Germain 1981, p. 342, pl. 129, figs 1-5.
Holland & Clark 1989, p. 22, pl. 18, fig. 5.
John 1983, p. 170, pl. 70, figs 3, 4.
Krammer & Lange-Bertalot 1988, p. 69, fig. 55: 1-10.
Common varieties:
var. linearis
Syn: Frustulia linearis Agardh fide W. Smith 1853
Nominate variety, description as above.
var subtilis (Grunow) Hustedt 1923
Syn: Nitzschia subtilis Grunow in Cleve & Grunow 1880
Valve narrowly lanceolate to linear-lanceolate, sometimes weakly curved (Krammer & Lange-Bertalot,
1988).
var. tenuis (W. Smith) Grunow in Cleve & Grunow 1880
Syn: Nitzschia tenuis W. Smith 1853
Valve longer and narrower. Valve weakly attenuate rather than strictly parallel.
Similar species: Nitzschia capitellata (p. 107)
Nitzschia filiformis (p. 111)
Nitzschia intermedia Hantzsch ex Cleve & Grunow 1880 (not described in this guide)
Nitzschia recta (p. 121)
Nitzschia sigma (p. 122)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread, mostly in lowland areas, rarely
abundant. Recorded in both epipelic and epilithic
assemblages.
Fig. 104. Nitzschia linearis: (a) Blackwood River, WA, 1200x; (b) Wimmera River, VIC, 1200x.

118
Nitzschia microcephala
Grunow in Cleve & Möller 1878 (Figs 105a-d)
Synonyms: None
Description: Valve short, lanceolate to linear-lanceolate (sometimes slightly elliptic), with slightly convex
margins sharply narrowing to subcapitate to markedly capitate ends. Raphe canal marginal. Fibulae small.
Central nodule absent. Transapical striae closely spaced, delicate, may not be distinguishable under LM.
Length 10-14 (7-19) µm, width 2-3 (2.3-4) µm, fibulae density 15-18 (9-19)/10 µm, striae density (30-41)
/10 µm.
Key references: Germain 1981, p. 358, pl. 135, figs 1-4.
Krammer & Lange-Bertalot 1988, p. 120, fig. 83; 10-18.
Common varieties: None
Similar species: Nitzschia desertorum (p. 109)
Nitzschia elegantula Grunow in Van Heurck 1881 (not described in this guide)
Nitzschia lacuum (p. 115)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be moderately abundant.
Common in both upland and lowland areas.
N. microcephala is easily recognised by its shortness
and distinctly capitate ends. The majority of specimens
encountered in streams are mostly elliptical-lanceolate
in shape. Recorded in both epipelic and epilithic
assemblages.
Fig. 105. Nitzschia microcephala: (a) Wimmera River, VIC, x1750; (b) Bremer River, SA, x1750; (c)
Blackwood River, WA, x1750; (d) Kororoit Creek, VIC, x1750.

119
Nitzschia palea
(Kützing) W. Smith 1856 (Figs 106a-c)
Synonyms: Refer to individual variety and form descriptions.
Description: Valve highly variable in shape, from narrow/broadly linear-lanceoate to linear with narrowly
elongated to pointedly rounded, subcapitate to capitate ends. Raphe canal marginal, fibulae small and
narrow, irregularly spaced, central nodule absent. Transapical striae moderately dense, (28-40)/10 µm, often
indistinguishable under LM, particularly in certain varieties (see below). Length 32-35 (15-70) µm, width
4-4.5 (2.5-5) µm, fibulae density 14 (9-17)/10 µm.
Key references: Foged 1978, p. 108, pl. 45, fig. 11, pl. 46, fig. 22.
Holland & Clark 1989, p. 22, pl. 18, figs 7, 8.
John 1983, p. 171, pl. 70, fig. 12.
Krammer & Lange-Bertalot 1988, p. 85, figs 59; 1-24, 60: 1-7.
Thomas 1983, p. 60, pl. 11, fig. 15.
Common varieties and forms:
var. palea
Syn: Nitzschia accommodata Hustedt 1949
Nitzschia pilum Hustedt 1942
Nominate variety described above.
var. tenuirostris Grunow in Van Heurck 1881
Valve elongate with sharply tapered ends. This variety is very similar to N. palea var. debilis and N.
gracilis (Krammer & Lange-Bertalot, 1988).
var. debilis (Kützing) Grunow in Cleve & Grunow 1880
Syn: Synedra debilis Kützing 1844
Valve narrowly linear-lanceolate.
form major Rabenhorst 1864
Syn: Nitzschia pilum Hustedt 1942
Valve longer and broader than nominate variety (Krammer & Lange-Bertalot, 1988).
Similar species: Nitzschia agnita (p. 105)
Nitzschia capitellata (p. 107)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 106. Nitzschia palea: (a-b) Ovens River,
VIC, x1750; (c) Mooki River, NSW, x1750.
Notes: Widespread and can be very abundant.
Frequently found in high numbers in hypertrophic
waters. Recorded in both epilithic and epipelic
assemblages.

120
Nitzschia perminuta
(Grunow) M. Peragallo 1903 (Fig. 107)
Synonyms: Nitzschia palea var. perminuta Grunow in Cleve & Grunow 1880
Nitzschia frustulum var. tenella Grunow in Van Heurck 1881
Nitzschia minutula Grunow in Van Heurck 1881
Nitzschia hiemalis Hustedt 1943
Description: Valve short, narrowly linear to linear-lanceolate, with sharply pointed, drawn out, subcapitate
to capitate ends. Raphe canal marginal and without a central nodule. Fibulae small, more or less irregularly
spaced,. Striae fine and parallel. Length 17.5 (8-45) µm, width 3 (2.5-3) µm, fibulae density 13 (10-16)/10
µm, striae density 25 (26-32)/10 µm.
Key references: Krammer & Lange-Bertalot 1988, p. 99, fig. 72: 1-23A.
Common varieties: None
Similar species: Nitzschia acidoclinata (not described in this guide)
Nitzschia bacillum (not described in this guide)
Nitzschia frustulum (p. 112)
Nitzschia lacuum (p. 115)
Nitzschia liebetruthii (p. 116)
Nitzschia palea (p. 119)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be moderately abundant.
Recorded in both epipelic and epilithic assemblages.
Fig. 107. Nitzschia perminuta, River Torrens, SA,
x1750.

121
Nitzscha recta
Hantzsch in Rabenhorst 1861-1879 (Figs 108a-b)
Synonyms: Nitzschia media Hantzsch 1860
Nitzschia rectiformis Hustedt 1943
Nitzschia garrensis Hustedt 1950
Nitzschia barvarica Hustedt 1953
Description: Valve elongate, linear to linear-lanceolate with drawn out, cuneate ends with capitate apices,
often deflected away from the raphid side. Raphe canal strongly eccentric-marginal and without a central
nodule. Fibulae distinctly long, widely and irregularly spaced. Striae highly dense, not usually visible under
LM. Length 50.5-72 (35-100) µm, width 4.5-6.5 (3.5-7) µm, fibulae density 6-7 (5-10)/10 µm, striae density
(35-52)/10 µm.
Key references: Foged 1978, p. 109, pl. 45, fig. 7.
Germain 1981, p. 344, pl. 131, figs 1-3.
Holland & Clark 1989, p. 22, pl. 18, fig. 4.
Krammer & Lange-Bertalot 1988, p. 20, fig. 12: 1-10.
Common varieties: None
Similar species: Nitzschia dissipata (p. 110)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 108. Nitzschia recta: (a-b) Jacksons
Creek, VIC, x1550.
Notes: Widespread and not usually abundant.
Recorded in both epipelic and epilithic assemblages.

122
Nitzschia sigma
(Kützing) W. Smith 1853 (Figs 109a-b)
Synonyms: Synedra sigma Kützing 1844
Description: Valve linear and distinctly sigmoid in girdle view. In valve view, weakly to strongly sigmoid,
linear-lanceolate, with gradually tapered, sharply rounded to capitate ends. Raphe canal marginal, fibulae
elongate, appearing almost tooth-like, and without central nodule. Transapical striae closely spaced and
finely punctate. Punctae often appear as wavy longitudinal lines. Length 68-72 (35-1000) µm, width 7-7.5
(4-15) µm, fibulae density 9 (7-12)/10 µm, striae density 16 (19-38)/10 µm.
Key references: Foged 1978, p. 110, pl. 46, figs 3, 4.
Germain 1981, p. 368, pl. 139, figs 1-6.
Holland & Clark 1989, p. 23, pl. 19, figs 2-4.
John 1983, p. 173, pl. 72, figs 10, 11.
Krammer & Lange-Bertalot 1988, p. 32, figs 23: 1-9, 24: 1.
Common varieties: None
Similar species: Nitzschia filiformis (p. 111)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 109. Nitzschia sigma: (a) Dandenong
Creek, VIC, x1750; (b) Gardiners Creek,
VIC, x1750.
Notes: Widespread but not usually abundant.
Preference for brackish waters. Recorded in both
epipelic and epilithic assemblages.

123
Nitzschia tubicola
Grunow in Cleve & Grunow 1880 (Figs 110a-c)
Synonyms: Nitzschia gandersheimiensis Krasske 1927
Nitzschia adamata Hustedt 1957
Description: Valve broadly lanceolate to linear-lanceolate, sharply tapered to cuneate ends, with distinctly
capitate apices. Some valves with weakly concave central margins, with a notably broad central nodule.
Raphe canal marginal, fibulae prominent. Transapical striae highly dense, mostly indistinguishable under
LM. Length 25-40 (14-70) µm, width 5-6 (3.5-6) µm, fibulae density 10-12 (7-13)/10 µm, striae density (29-
35)/10 µm.
Key references: Krammer & Lange-Bertalot 1988, p. 90, figs 63: 8-12, 64: 1-16.
Common varieties: None
Similar species: Nitzschia capitellata (p. 107)
Nitzschia palea (p. 119)
Nitzschia recta (p. 121)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 110. Nitzschia tubicola: (a) Perup River,
WA, x1750, (b-c) Merri Creek, VIC, x1900.
Notes: Widespread and moderately abundant.
Recorded in both epipelic and epilithic assemblages.

124
Nitzschia umbonata
(Ehrenberg) Lange-Bertalot 1978 (Figs 111a-b)
Synonyms: Navicula umbonata Ehrenberg 1838
Surirella thermalis Kützing 1844
Nitzschia thermalis Grunow 1862
Nitzschia stagnorum Rabenhorst 1860
Nitzschia diducta Hustedt 1938
Nitzschia fossalis Hustedt 1942
Description: Valve broadly linear, with parallel to weakly concave margins, and short, cuneate, subrostrate
to subcapitate ends. Raphe canal marginal, fibulae short, somewhat irregularly spaced and with a central
nodule. Transapical striae relatively dense, parallel in the centre becoming weakly radial at the ends,
sometimes appearing wavy, usually visible under LM. Length 48 (22-125) µm, width 7.5 (6-9) µm, fibulae
density 8 (7-10)/10 µm, striae density (24-30)/10 µm.
Key references: Germain 1981, p. 340, pl. 129, figs 7, 8.
Krammer & Lange-Bertalot 1988, p. 65, figs 51: 1-6a.
Common varieties: None
Similar species: Hantzschia amphioxys (p. 80)
Nitzschia capitellata (p. 107)
Tryblionella apiculata (p. 153)
Tryblionella hungarica (p. 156)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 111. Nitzschia umbonata; (a-b)
Dandenong Creek, VIC, x2000.
Notes: Widespread and often abundant. Limited to
high nutrient waters. Recorded in both epipelic and
epilithic assemblages.

125
Genus Pinnularia
Key to the common species
1a. Striae very short, forming broad axial and central areas ....... Other species not included in this guide 1
1b. Striae not so short, axial and central area may be distinct but not so broad ........................................... 2
2a. Striae noticeably wide, £6/10 mm .......................................................................... Pinnularia borealis
2b. Striae not as wide, ³6/10 mm .............................................................................................................. 3
3a. Central area narrowly rounded; striae broad (6 -12/10 mm); large forms ............ Pinnularia viridiformis
3b. Central area forming a wide rectangular (to circular) fascia; striae ³10/10 mm .................................... 4
4a. Valves narrow (£7 mm) with central area distinct from axial area; striae 12-14/10 mm ............................
......................................................................................................................... Pinnularia subcapitata
4b. Valves wider (³7 mm) ......................................................................................................................... 5
5a. Central area occurring as a progressive widening of axial area; ends capitate ........... Pinnularia braunii
5b. Central area distinct from axial area; ends rostrate to capitate ..................................................................
............................................................................................ Other species not included in this guide2
1Includes P. brevicostata Cleve 1891, P. gibba Ehrenberg 1841 and other similar species.
2Includes P. interrupta Smith 1853 and P. microstauron (Ehrenberg) Cleve 1891.

126
Pinnularia borealis
Ehrenberg(Fig. 112)
Synonyms: Refer to individual variety descriptions.
Description: Valve linear, with slightly convex margins and broadly rounded ends. Axial area narrow,
gradually widening towards the central area. Raphe distinctly curved so that proximal ends turn towards one
side. Distal raphe ends with distinct hook-shaped terminal fissure. Central area transversely expanded,
circular to rectangular. Striae noticeably wide, parallel to slightly radial in the central region tending to
slightly convergent distally. Length 36-50 (24-110) µm, width 7-11 (5-18) µm, striae 4 (4-6)/10 µm.
Key references: Foged 1978, p. 113, pl. 33, fig. 15, pl. 34, fig. 9.
Holland & Clark 1989, p. 23, pl. 20, figs 6-8.
John 1983, p. 125, pl. 53, fig. 4.
Krammer 1992, p. 57, figs 9:1-20, 10:1-7.
Krammer & Lange-Bertalot 1989, p. 405, figs 177: 1-12, 178: 7.
Patrick & Reimer 1966, p. 618, pl. 58, fig. 13.
Common varieties
var. borealis
Syn: Navicula borealis (Ehrenberg) Kützing 1844
Nominate variety, description as above.
var rectangularis Carlson 1913
Striae widely spaced and alternating on opposite sides of the valve (Patrick & Reimer, 1966).
var. scalaris (Ehrenberg) Rabenhorst 1864
Valve with continuous central area (Hustedt, 1959).
var. thuringiaca(Rabenhorst) Krammer 1992
Syn: Pinnularia lata f. thuringiaca (Rabenhorst) Mayer 1916
Pinnularia lata var.rabenhorstii (Grunow) Cleve 1895
Valves with parallel margins and acute ends.
var. undulata Hustedt in A. Schmidt et. al. 1934
Valve with undulating margins and broadly rounded ends.
Similar species: Hippodonta capitata (p. 86)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Generally restricted to upland areas and
usually in low abundance. Mainly aerophilous.
Fig. 112. Pinnularia borealis, Bremer River , SA,
x1750.

127
Pinnularia braunii
(Grunow) Cleve 1895 (Fig. 113)
Synonyms: Refer to individual variety descriptions.
Description: Valve lanceolate with subcapitate to strongly capitate ends. Axial area narrow distally,
progressively widening towards the central area. Central area a conspicuous, wide, transverse fascia. Striae
shorter and strongly radial in the central region becoming strongly convergent distally. Length 39 (30-60)
µm, width 5.5 (7-12) µm, striae 13 (10-12)/10 µm.
Key references: Foged 1978, p. 113, pl. 33, figs 12, 14.
Germain 1981, p. 244, pl. 88, fig. 17.
Holland & Clark 1989, p. 23, pl. 20, fig. 5.
John 1983, p. 125, pl. 53, fig. 6.
Krammer & Lange-Bertalot 1986, p. 416, fig. 187: 1-5.
Patrick & Reimer 1966, p. 594, pl. 55, fig. 3.
Thomas 1983, p. 63, pl. 10, figs 4, 5.
Common varieties:
var. braunii
Syn: Navicula brauniana Grunow ex. A. Schmidt 1876
Navicula braunii Grunow in Van Heurck 1880
Pinnularia brauniana (Grunow) Mills 1934
Nominate variety, description as above.
var. amphicephala (A. Mayer) Hustedt 1930
Syn: Pinnularia amphicephala A. Mayer 1917
Valve more linear, with narrower axial area and less attenuated apices (Patrick & Reimer, 1966).
Similar species: None
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Generally restricted to upland areas, not
usually abundant, and mainly aerophilous. Not as
common as Pinnularia borealis.
Fig. 113. Pinnularia braunii, Murrumbidgee River, NSW, 2300.

128
Pinnularia subcapitata
Gregory 1856 (Figs 114a-d)
Synonyms: Refer to individual variety descriptions.
Description: Valve linear with broadly rounded, subcapitate to capitate ends. Axial area narrow, often
widened towards the central area. Small terminal nodule present. Central area transapically widened, forming
a broad rectangular to circular fascia which extends to the valve margin. Striae radial in the central region,
becoming strongly convergent distally. Length 28-37 (22-62)µm, width 5-5.5 (4-7)µm, striae 13-14 (12-
14)/10µm.
Key references: Foged 1978, p. 118, pl. 33, figs 7, 8.
Germain 1981, p. 244, pl. 88, figs 1-13.
Holland & Clark 1989, p. 24, pl. 19, figs 9, 12, 13.
Krammer 1992, p. 107, figs 37:17-31, 38:1-18, 39:1-14.
Krammer & Lange-Bertalot 1986, p. 426, fig. 193: 1-18.
Patrick & Reimer 1966, p. 596, pl. 55, figs 8-10.
Common varieties
var. subcapitata
Syn: Pinnularia hilseana Janisch in Hilse 1860
Pinnularia subcapitata var. stauroneiformis A. Mayer 1917
Nominate variety, description as above.
var. paucistriata (Grunow in Van Heurck) Cleve 1895
Syn: Navicula subcapitata var. paucistriata Grunow in Van Heurck 1880
Valve with broadly, rounded rostrate ends, and broad, transverse fascia (Patrick & Reimer 1966).
Similar species: None
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 114. Pinnularia subcapitata: (a)
Blackwood River, WA, x1600; (b) East
Tanjil River, VIC, x1750; (c) Deep Creek,
VIC, x2090; (d) Pinnularia cf. subcapitata,
Plenty River, VIC, x1750.
Notes: Widespread but not usually abundant.
Recorded in epipelic and epilithic assemblages, and
can be aerophilous.

129
Pinnularia viridiformis
Krammer 1992 (Fig. 115)
Synonyms: Pinnularia streptoraphe var. minor (Cleve) Cleve 1895
Description: Valve linear, sometimes weakly convex, with broadly rounded ends. Axial area relatively
narrow, widened at the middle. Raphe compound, noticeably crooked, terminating distally in a hook-shaped
configuration. Proximal raphe ends deflected to one side, central area narrowly rounded. Striae radial in
middle of valve, becoming convergent distally. Striae crossed by a wide longitudinal band, often indistinct.
Length 60 (50-170) µm, width 11 (10-30) µm, striae density 7-8 (6-12)/10 µm.
Key references: Krammer 1992, p. 158, figs 2:4, 65:1, 67:1-4.
Common varieties: None
Similar species: None
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but rarely abundant. More
common in upland regions. Recorded in epipelic
and epilithic assemblages and can be aerophilous.
Fig. 115. Pinnularia viridiformis, Jacksons Creek, VIC, x1850.

130

130
Pseudostaurosira brevistriata
(Grunow in Van Heurck) Williams & Round 1987 (Figs 116a-b)
Synonyms: Refer to individual variety descriptions.
Description: Valve linear-lanceolate, lanceolate to elliptical, with broadly rounded to attenuated subrostrate
ends. Axial area (pseudoraphe) broadly lanceolate. Striae marginal, distinctly shortened and weakly radial.
Striae sparsely punctate, with usually only two to three punctae per stria. Length 12-24 (11-30) µm, width
4.5 (3-5) µm, striae density 13-16 (12-17)/10 µm.
Key references: Germain 1981, p. 68, pl. 20, figs 22-31.
Holland & Clark 1989, p. 15, pl. 8, fig. 10.
John 1983, p. 42, pl. 16, figs 1-3.
Krammer & Lange-Bertalot 1991, p. 162, figs 130: 9-16, 131: 7.
Patrick & Reimer 1966, p. 128, pl. 4, figs14-16.
Common varieties:
var. brevistriata
Syn: Fragilaria brevistriata Grunow in Van Heurck 1885
Fragilaria brevistriata var. subacuta Grunow in Van Heurck 1881
Fragilaria brevistriata var. pusilla Grunow in Van Heurck 1881
Nominate variety described above.
var. capitata Hérib 1903
Syn: Fragilaria brevistriata var. subcapitata Grunow in Van Heurck 1881
Distinguished by distinctly capitate valve ends.
var. inflata (Pantocsek) Hustedt 1930
Syn: Fragilaria inflata Pantocsek 1902
Valve broadly lanceolate with elongated rostrate ends (Patrick & Reimer 1966).
Similar species: Fragilaria zeilleri Héribaud 1902 (not described in this guide)
Staurosira construens (p. 141)
Staurosirella pinnata (p. 143)
Tabularia parva Williams and Round 1990 (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 116. Pseudostaurosira brevistriata: (a)
Murray River, Tallangatta, x1150; (b) Deep
Creek, VIC, x1600.
Notes: Widespread and can be very abundant (some
assemblages recorded have been monospecific). Wide
ecological tolerances, particularly for nutrients and pH.
In SE Australian aquatic systems it appears to show a
preference for turbid environments. This taxon is
facultative planktonic and is a common plankton in the
lower Murray River. Valves in girdle view can easily
be confused with Staurosira construens varieties.

131
Reimeria sinuata
(Gregory) Kociolek & Stoermer 1987 (Fig. 117)
Synonyms: Cymbella abnormis Grunow 1880
Cymbella sinuata Gregory 1858
Description: Valve linear-elliptical, slightly dorsiventral. Dorsal margin generally smoothly convex, whilst
the ventral margin varies from convex with a central expansion to undulate with several expansions. Valve
ends broadly rounded, sub-capitate. Axial area straight, narrow, and located closer to the ventral margin.
Raphe filiform, generally straight but sometimes slightly curved. Central area conspicuously one-sided,
extending to the ventral margin. A shortened stria is present on the dorsal side of the central area. A single
stigma is also located to the dorsal side of the central area. Striae punctate, slightly radial, but appearing
parallel in some specimens. Length 15-16 (9-40) µm, width 4.5 (3.5-9) µm, striae density 13-15 (8-16)/10
µm.
Key references: Holland & Clark 1989, p. 13, pl. 4, fig. 2.
Krammer & Lange-Bertalot 1986, p. 341, fig. 148: 10-17.
Patrick & Reimer 1975, p. 51, pl. 9, figs 3, 4.
Common varieties: None
Similar species: None
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread, particularly in low nutrient, low
conductivity, circumneutral to acidophilous sites. Most
commonly found in epipelic and epilithic assemblages.
Fig. 117. Reimeria sinuata, Kiewa River, VIC, x1800.

132
Rhoicosphenia abbreviata
(Agardh) Lange-Bertalot 1980 (Figs 118a-d)
Synonyms: Gomphonema abbreviatum Agardh 1831
Gomphonema curvatum Kützing 1833
Rhoicosphenia curvata (Kützing) Grunow ex Rabenhorst 1864
Description: Valve heteropolar, linear-lanceolate to clavate, with broadly to narrowly rounded ends. Raphid
valve concave in girdle view. Axial area narrowly lanceolate, raphe filiform with distinct proximal ends.
Central area absent to slightly transverse. Striae in the central region marginally radial and more widely
spaced, becoming almost parallel towards the ends. Araphid valve convex in girdle view. Axial area
narrowly linear, with a vestigial raphe (raphe very short at either end) that is often difficult to distinguish.
Central area absent. A distinct pseudoseptum (internally thickend valve margins) is present at the valve ends.
Length 22-40 (10-75) µm, width 3.5-5 (3-8) µm, striae density 10 (11-24)/10 µm.
Key references: Foged 1978, p. 122, pl. 17, figs 1-3.
Germain 1981, p. 118, pl. 44, figs 21-25, pl. 168, fig. 13.
Holland & Clark 1989, p. 25, pl. 21, figs 4-11.
Krammer & Lange-Bertalot 1986, p. 381, fig. 91: 20-28.
Patrick & Reimer 1966, p. 282, pl. 20, figs 1-5.
Common varieties: None
Similar species: Gomphonema spp. (pp. 68-76)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 118. Rhoicosphenia abbreviata: (a-b)
Surrey River, VIC, x1750; (c) Surrey River,
VIC, x1875; (d) Dawesley Creek, SA, x1650.
Notes: Widespread and can be very abundant,
particularly in lowland areas. Preference for alkaline
waters. Poor indicator of nutrient levels. Recorded in
both epipelic and epilithic assemblages.

133
Genus Rhopalodia
Key to the common species
1a. Valve “bracket” –shaped ({}); costae parallel or slightly radial .................................Rhopalodia gibba
1b. Valve with rounded dorsal side ............................................................................................................ 2
2a. Punctae density < 15/10 mm; ventral side usually arched ..................................... Rhopalodia musculus
2b. Punctae density > 15/10 mm; ventral side more or less straight ............................ Rhopalodia brebisonii
Rhopalodia brebissonii
Krammer 1987 (Figs 119a-b)
Synonyms: Rhopalodia musculus var. succinta sensu Fricke in A. Schmidt 1905
Description: Valve relatively small, strongly dorsiventral, dorsal margin strongly convex ± with central
notch, ventral margin straight to slightly convex. Valve ends ventrally deflected and sharply rounded. Raphe
canal relatively distinct, fibulae appearing robust in LM. Transapical costae robust and radial throughout the
valve. Two to four coarsely punctate striae present between each pair of costae. Length 24-29 (15-40) µm,
width 5-6 (12-20) µm, costae density (3-6) /10 µm, striae density 16-17 (17-22)/10 µm.
Key references: Krammer & Lange-Bertalot 1988, p. 164, fig. 113: 7-13, 113A: 7-12.
Common varieties: None
Similar species: Rhopalodia acuminata Krammer 1987 (not described in this guide)
Rhopalodia gibba (p. 134)
Rhopalodia gibberula (Durrenberg) O. Müller 1899 (not described in this guide)
Rhopalodia musculus (p. 135)
Rhopalodia operculata (Agardh) Hakansson 1979 (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 119. Rhopalodia brebissonii: (a) Wild
Dog Creek, SA, x1720; (b) Adelong River,
NSW, x1790.
Notes: Widespread and can be moderately abundant.
Recorded in both epipelic and epilithic assemblages.

134
Rhopalodia gibba
(Ehrenberg) O. Müller 1895 (Fig. 120)
Synonyms: Refer to individual variety descriptions.
Description: Cell linear in girdle view, central regions slightly swollen, with small central notches and
broadly rounded ends. In valve view, narrowly elongate, more or less linear, dorsal margin weakly to
strongly convex in the centre, most with central notch, ventral margin straight. Valve with elongate,
gradually tapered ends that are bent ventrally and with acutely pointed apices. Raphe canal located along the
dorsal margin, fibulae more or less distinct. Transapical costae (thickened ribs) parallel in the centre,
becoming strongly radial distally. Usually two to three striae present between each pair of costae. Striae
coarsely punctate. Length 65 (22-300) µm, width 10 (18-30) µm, costae density 8 (12-17)/10 µm.
Key references: Foged 1978, p. 122, pl. 42, figs 12, 14.
Germain 1981, p. 320, pl. 119, figs 1-5.
Holland & Clark 1989, p. 25, pl. 22, fig. 4.
John 1983, p. 161, pl. 67, figs 9, 10.
Krammer & Lange-Bertalot 1988, p. 159, figs 110: 1, 111: 1-13.
Patrick & Reimer 1975, p. 189, pl. 28, fig. 1.
Thomas 1983, p. 68, pl. 11, fig. 5.
Common varieties:
var. gibba
Syn: Navicula gibba Ehrenberg 1932
Epithemia gibba (Ehrenberg) Kützing 1844
Epithemia ventricosa Kützing 1844
Rhopalodia ventricosa (Kützing) O. Müller 1895
Nominate variety, description as above.
var. parallela (Grunow) H. & M. Peragallo 1897-1908
Syn: Rhopalodia parallela (Grunow) O. Müller 1895
Valve extremely linear. Striae composed of double rows of punctae. Patrick & Reimer (1975) suggest
that it should not be considered a variety of R. gibba because of this feature.
Similar species: Rhopalodia brebissonii (p. 133)
Rhopalodia musculus (p. 135)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be abundant. Mostly
found in lowland, alkaline streams. Recorded in both
epipelic and epilithic assemblages.
Fig. 120. Rhopalodia gibba, Surrey River, VIC, x1550.

135
Rhopalodia musculus
(Kützing) O. Müller 1899 (Figs 121a-c)
Synonyms: Epithemia musculus Kützing 1844
Rhopalodia gibberula var. musculus Muschler 1908
Description: In girdle view, valve broadly elliptical with broadly rounded ends. In valve view, valve with
strongly dorsiventral, lunate, dorsal margin strongly convex ± with shallow central notch, ventral margin
concave. Valve ends weakly deflected ventrally, with sharply rounded apices. Raphe canal prominent.
Transapical costae radiate. Two to six coarsely punctate striae between each pair of costae. Length 37-48
(12-80) µm, width 10-11 (10-40) µm, costae density (3-5)/10 µm, striae density 16 (15-20)/10 µm.
Key references: Foged 1978, p. 123, pl. 42, figs 11, 13.
Germain 1981, p. 322, pl. 120, figs 4, 5.
Holland & Clark 1989, p. 25, pl. 22, figs 7-10.
Krammer & Lange-Bertalot 1988, p. 163, figs 110: 4, 114; 1-8.
Patrick & Reimer 1975, p. 191, pl. 28, fig. 5.
Common varieties: None
Similar species: Rhopalodia brebissonii (p. 133)
Rhopalodia gibba (p. 134)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 121. Rhopalodia musculus: (a) Wild Dog
Creek, SA, x1500; (b) Bremer River, SA, x
1500; (c) River Torrens, SA, x1450.
Notes:Widespread and can be moderately abundant.
Good indicator of alkaline waters. Most commonly
epiphytic but also recorded in epipelic and epilithic
assemblages.

136
Genus Sellaphora sensu Gell et al. (1999) and related genera
Key to the common species
1a. Longitudinal furrows present along raised axial area ................................................ Sellaphora pupula
1b. Longitudinal furrows absent ................................................................................................................ 2
2a. Striae density > 24/10 µm ........................................................................................... Eolimna minima
2b. Striae density < 24/10 µm .................................................................................. Sellaphora seminulum
Eolimna minima
(Grunow) Lange-Bertalot 1997 (Figs 122a-b)
Synonyms: Navicula minutissima Grunow 1860 non Rabenhorst 1853
Navicula atomoides Grunow in Van Heurck 1880
Navicula minima Grunow in Van Heurck 1880
Navicula tantula Hustedt 1943
[Sellaphora minima sensu Gell et al. 1999]
Description: Valve relatively small, elliptical, linear-elliptical to linear, with broadly rounded ends. Axial
area narrow and linear, often appearing slightly arcuate. Raphe filiform. Central area widened, transversely
rectangular, almost reaching the margins due to numerous equally shortened medial striae. Transapical striae
relatively densely spaced, distinctly radial throughout the valve. Length 10-13 (5-18) µm, width 3-4 (2-4.5)
µm, striae density 28-30 (25-30)/10 µm.
Key references: Germain 1981, p. 232, pl. 85, fig. 41.
Krammer & Lange-Bertalot 1986, p. 229, fig. 76: 39-47.
Patrick & Reimer 1966, p. 488, pl. 46, figs 17, 18.
Common varieties: None
Similar species: Achnanthidium minutissimum (p. 10)
Eolimna subminuscula (p. 85)
Mayamaea atomus (p. 87)
Sellaphora seminulum (p. 138)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 122. Eolimna minima: (a-b) Dandenong
Creek, VIC, x2850.
Notes: Widespread and can be very abundant. This
species differs little from Sellaphora seminulum except
for possessing a higher density of striae in the central
region (greater than 24/10 µm), and a reduced central
area. Presence usually indicates nutrient enrichment.
Found in epipelic and epilithic assemblages.

137
Sellaphora pupula
(Kützing) Mereschkowsky 1902 (Figs 123a-c)
Synonyms: Refer to individual variety descriptions.
Description: Valve shape highly variable from linear-lanceolate, elliptical to linear-elliptical. Valve ends
broadly rounded, sub-capitate to capitate. Axial area straight and narrow, somewhat raised, raphe filiform.
Longitudinal furrows present on either side of the axial area. Distal axial areas expanded laterally and
conspicuously absent of striae. Proximal raphe endings may be just slightly deflected to one side. Striae on
either side of the central area variously shortened to form a transverse fascia in the shape of a bow tie. Striae
strongly radial in the central region, and either becoming less radial, or parallel to convergent distally.
Length 19-35.5 (10-90) µm, width 6-8.5 (4.2-21) µm, striae density 20-22 (16-26)/10 µm.
Key references: Foged 1978, p. 96, pl. 28, figs 7, 9.
Germain 1981, p. 205, pl. 78, figs 4-12.
Holland & Clark 1989, p. 21, pl. 15, figs 5, 7, pl. 16, fig. 16.
John 1983, p. 96, pl. 41, fig. 3.
Krammer & Lange-Bertalot 1986, p. 189, fig. 68: 1-21.
Patrick & Reimer 1966, p. 495, pl. 47, figs 7-12.
Thomas 1983, p. 54, pl. 7, figs 24, 25.
Common varieties: Mann and Droop (1995) suggest as many as 20 varieties are distinguishable.
var. pupula
Syn: Stauroneis rectangularis Gregory 1854
Navicula pupula Kützing 1844
Nominate variety, description as above.
var. capitata Skvortzow & Meyer 1928
Valve ends with broadly capitate ends.
Similar species: Sellaphora bacillum Mann 1989 (not described in this guide)
Sellaphora laevissima Mann 1989 (not described in this guide)
Sellaphora mutata Krasske (Lange Bertalot) 1996 (not described in this guide)
Sellaphora pseudopupula (Krasske) Hustedt 1930 (not described in this guide)
Sellaphora seminulum (p. 138)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 123. Sellophora pupula: (a)
Tookayerta Creek, SA, x1650; (b)
Wallpolla Creek, VIC, x1730; (c)
Blackwood River, WA, x1700.
Notes: Widespread and can be moderately abundant.
Broad tolerance may reflect the existence of several as yet
undistinguished taxa. Found in epipelic and epilithic
assemblages.

138
Sellaphora seminulum
(Grunow) Mann 1990 (Figs 124a-d)
Synonyms: Refer to individual variety descriptions.
Description: Valve linear-elliptical, with slightly convex central area and broadly rounded ends. Axial area
straight and narrow. Central area transversely widened, reaching almost 2/3 of the distance to margins. Striae
radial throughout valve, except in the central area where shortened striae appear almost parallel. Striae
density 20 (18-22)/10 µm, length 8.5-12.5 (3-21) µm, width 4 (2-5) µm.
Key references: Germain 1981, p. 230, pl. 85, figs 22-30, pl. 158, figs 3-5.
Krammer & Lange-Bertalot 1986, p. 230, fig. 76: 30-36.
Patrick & Reimer 1966, p. 489, pl. 46, fig. 19.
Common varieties:
var. seminulum
Syn: Navicula seminulum Grunow 1860
Nominate variety, description as above.
var. hustedtii Patrick 1959
Valve linear with broadly rounded ends, small specimens elliptical, central area transverse and rounded,
striae 18-22/10 µm, length 4-18 µm, width 3-5 µm (Patrick & Reimer, 1966).
var. intermedia Hustedt 1942
Valve linear elliptical.
Similar species: Eolimna minima (p. 136)
Eolimna subminuscula (p. 84)
Navicula submuralis (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be moderately abundant.
Indicates nutrient enrichment. Recorded in epipelic and
epilithic assemblages.
Fig. 124. Sellaphora seminulum: (a-d) Dandenong
Creek, VIC, x1500; Eolimna cf. minima, (e)
Dandenong Creek, VIC, x1500.

139
Genus Staurophora
Key to the common species
1a. Valve length > 50 mm ............................................................................................. Staurophora salina
2a. Valve length < 50 mm ...................................................................................... Staurophora wislouchii
Staurophora salina
(W. Smith) Mann 1990 (Fig. 125)
Synonyms: Stauroneis salina W. Smith 1853
Description: Valve lanceolate, with smoothly convex margins and sharply rounded ends. Valve face
convex. Axial area narrow and linear, sometimes slightly lanceolate. Raphe filiform. Central area a widely
transverse fascia reaching the valve margins. The fascia may be apically widened at the margins. Transapical
striae relatively coarse and weakly radial throughout the valve. Has a rounded valve face and will often sit
obliquely. Length 58 (50-110) µm, width 12 (11-20) µm, striae density 20 (18-25)/10 µm.
Key references: Germain 1981, p. 157, pl. 60, fig. 23.
Krammer & Lange-Bertalot 1986, p. 250, fig. 91: 14, 15.
Common varieties: None
Similar species: Staurophora wislouchii (p. 140)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Restricted to streams with high conductivity.
Mostly recorded in epipelic and epilithic assemblages.
Fig. 125. Staurophora salina, Salt Creek, SA, x1750.

140
Staurophora wislouchii
(Poretzky & Anisimowa) Mann 1990 (Figs 126a-d)
Synonyms: Stauroneis wislouchii Poretzky & Anisimowa 1933
Description: Valve elliptical-lanceolate to rhomboid-lanceolate, with broad, rounded ends. Axial area
narrow and linear, raphe filiform. Central area transapically widened to the valve margins, forming a narrow
fascia. Several extremely short medial striae ± present. Transapical striae weakly radial throughout the valve.
Striae denser towards the ends. Has a rounded valve face and will often sit obliquely. Striae finely punctate,
but not usually seen under LM. Length 24-47 (20-38) µm, width 9-13 (5-9) µm, striae density 20-24 (22-
28)/10 µm.
Key references: Krammer & Lange-Bertalot 1986, p. 250, fig. 91: 16, 17.
Common varieties: None
Similar species: Staurophora salina (p. 139)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread in brackish waters. Most
commonly found in epipelic and epilithic assemblages.
Fig. 126. Staurophora wislouchii: (a-b) Bremer River, SA, x 1750; (c) Inman River, SA, x1750; (d) Lindsay
River, VIC, x1750.

141
Genus Staurosira and related genera
Key to the common species
1a. Valves generally > 11mm in length with marginal striae ........................... Pseudostaurosira brevistriata
1b. Valves variable in shape, mostly < 11mmin length, with longer striae ................................................... 2
2a. Striae density between 5-12/10 mm ..................................................................... Staurosirella pinnata
2b. Striae density > 12/10 mm .................................................................................. Staurosira construens
Staurosira construens
Ehrenberg 1843 (Figs 127a-b)
Synonyms: Refer to individual form and variety descriptions.
Description: Valve extremely variable in shape, ranging from elliptical, elliptical-lanceolate, linear-
lanceolate to almost cruciform, with drawn out, bluntly rounded to slightly capitate ends. Axial area
(pseudoraphe) linear to lanceolate, sometimes absent. Central area absent. Transapical striae generally
widely spaced and clearly radial throughout valve. Punctae may be visible. Cells solitary or forming long
straight chains. [Morphometrics: see individual variety and form descriptions below].
Key references: Foged 1978, p. 63, pl. 8, fig. 6.
Germain 1981, p. 68, pl. 21, figs 1-43.
Holland & Clark 1989, p. 15, pl. 8, fig. 9.
John 1983, p. 42, pl. 16, figs 4-6.
Krammer & Lange-Bertalot 1991, p. 153, figs 132: 1-34, 129: 21-27, 131: 5, 6.
Patrick & Reimer 1966, p. 125, pl. 4, fig. 4.
Common forms and varieties:
f. construens (Ehrenberg) Hustedt 1957
Syn: Fragilaria construens f. construens (Ehrenberg) Hustedt 1957
Valve elliptical to almost cruciform, sometimes asymmetrically so, with a strongly convex swelling in
the centre and drawn out, rounded to slightly capitate ends. Length 10-17 µm, width 5.5-10 µm, striae
density 12-22/10 µm.
f. venter (Ehrenberg) Hustedt 1957
Syn: Fragilaria venter Ehrenberg 1854
Fragilaria construens var. venter (Ehrenberg) Grunow in Van Heurck 1881
Fragilaria construens f. venter (Ehrenberg) Hustedt 1957
Valve elliptical, elliptical-lanceolate to rhomboid, with slightly drawn out, rostrate to acutely rounded
ends.
var. subsalina Hustedt 1957
Syn: Fragilaria construens var. pumila Grunow in Van Heurck 1881
Fragilaria construens var. subsalina Hustedt 1925
Fragilaria construens f. subsalina (Hustedt) Hustedt 1957
Valve linear to linear-lanceolate with bluntly rounded ends. Punctae clearly visible.

142
Staurosira construens cont.
f. binodis (Ehrenberg) Hustedt 1957
Syn: Fragilaria binodis Ehrenberg 1854
Fragilaria construens var. binodis (Ehrenberg) Grunow 1862
Fragilaria construens f. binodis (Ehrenberg) Hustedt 1957
Valve strongly constricted in the middle, therefore resulting in two undulations per margin. Valve
ends apiculate to capitate.
f. exigua (W. Smith) Hustedt 1959
Syn: Triceratium exiguum W. Smith 1856
Fragilaria exigua (W. Smith) Lemmerma nn 1908
Fragilaria construens var. exigua (W. Smith) Schulz 1922
Fragilaria construens f. exigua (W. Smith) Hustedt 1959
Valve with three poles, margins in the centre convex, drawn out and capitate ends.
Similar species: Pseudostaurosira brevistriata (p. 130)
Staurosira elliptica (figs 127c-d) (not described in this guide)
Staurosirella pinnata (p. 143)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be very abundant.
Williams & Round (1987) separated Staurosira from
Fragilaria on the basis of morphological features
such as the absence of rimoportulae (tubes opening to
the inside of the valve), which can only be seen
clearly using a SEM. Nethertheless, most species
belonging to this genus are relatively easily
differentiated from Fragilaria due to their valve size,
shape and distinctive striae. Facultative planktonic. A
common planktonic species in the lower Murray
River. Valves form chains and so are mostly in girdle
view, making them diffcult to distinguish from
Pseudostaurosira brevistriata and Staurosirella
pinnata.
Fig. 127. Staurosira construens var. construens: (a-b) Wimmera River, VIC, x 1750; Staurosira elliptica (c)
Wimmera River, VIC, x1750; (d) Mount Barker Creek, SA, x1750.

143

143
Staurosirella pinnata
(Ehrenberg) Williams & Round 1987 (Figs 128a-b)
Synonyms: Refer to individual variety descriptions.
Description: Valve elliptical to elliptical-linear with broad to slightly drawn out rounded ends. Axial area
(pseudoraphe) extremely narrow, occasionally slightly lanceolate. Central area absent. Transapical striae
coarse, finely lineolate, and weakly radial thoughout the valve. Striae may by crossed by fine longitudinal
lines. Length 6-15 (3-35)µm, width 2.5-3.5 (2-8)µm, striae density 10-12 (6-12)/10µm.
Key references: Foged 1978, p. 64, pl. 8, fig. 7.
Germain 1981, p. 72, pl. 21, figs 44-52, pl. 156, fig. 3.
Krammer & Lange-Bertalot 1991, p. 156, figs 112: 15, 16, 117: 3, 131: 3, 4, 133: 1-23.
Patrick & Reimer 1966, p. 127, pl. 4, fig. 10.
Common varieties:
var. pinnata
Syn: Fragilaria pinnata Ehrenberg 1843
Fragilaria elliptica Schmacher 1867
Nominate variety, description as above.
var. intercedens (Grunow) Hustedt 1931
Syn: Odontidium mutabile W. Smith 1856
Fragilaria mutabile (W. Smith) Grunow 1862
Fragilaria mutibile var. intercedens Grunow in Van Heurck 1881
Fragilaria pinnata var. intercedens (Grunow) Hustedt 1931
Valve linear, rounded ends, broad pseudoraphe and coarsely striate.
Similar species: Pseudostaurosira brevistriata (p. 130)
Staurosira construens (p. 141)
Staurosira elliptica (not described in this guide) (figs 127c-d)
Staurosirella leptostauron (Ehrenberg) Williams & Round 1987 (not described in this
guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 128. Staurosirella pinnata: (a) Mount
Barker Creek, SA, x1750; (b) Salt Creek,
SA, x1750.
Notes: Widespread and can be very abundant. Very broad
ecological tolerances and as such is usually a poor
indicator taxon. Facultative planktonic. Common
planktonic species in the lower Murray River. Chain
forming, valves usually in girdle view. Can easily be
confused with Staurosira construens var. venter.
Northern hemisphere diatomists are attempting to review
this taxon, however it is beyond the scope of this
document to address these complex issues.

144
Genus Surirella
Key to the common species
1a. Valves > than 80 mm in length1.............................................. Other species not included in this guide
1b. Valves < than 80 mm in length ............................................................................................................. 2
2a. Valve isopolar, sides more or less parallel2................................................................ Surirella angusta
2b. Valve heteropolar ................................................................................................................................ 3
3a. Valve distinctly oval to ‘pear-shape’ .................................................................... Surirella brebissonii3
3b. Valve linear-oval ........................................................................................................ Surirella minuta
1Forms with maximum lengths exceeding 80 mm are occasionally encountered, particularly in saline waters
2There are several other species of Surirella that can appear isopolar; however, most of these tend to be
either broad-elliptical rater than linear in outline, or somewhat larger. Examples of such taxa can be seen in
Krammer & Lange-Bertalot (1988).
3It is difficult to distinguish this taxon from small forms of S. ovalis (not included in this guide) using light
microscopes.

145
Surirella angusta
Kützing 1844 (Figs 129a-d)
Synonyms: Surirella angustata Hustedt 1930
Description: Valve isopolar to somewhat heteropolar, linear with sharply pointed, apiculate ends. Axial area
extremely narrow, linear. Raphe canal located within the narrow, raised wing that follows the circumference
of the valve. Valve with prominent marginal ribs extending from the valve margins to the axial area.
Marginal ribs parallel in the middle of the valve, becoming strongly radial towards the ends. Transapical
striae extremely dense, usually not distinguishable under LM. Length 24-40 (18-70) µm, width 7.5-11 (6-15)
µm, marginal rib density (5.5-8) /10 µm, striae density (23-28) /10 µm.
Key references: Foged 1978, p. 127, pl. 47, figs 5-7.
Germain 1981, p. 384, pl. 152, fig. 22.
Holland & Clark 1989, p. 26, pl. 24, figs 5, 7.
John 1983, p. 178, pl. 65, figs 1-4.
Krammer & Lange-Bertalot 1988, p. 187, figs 133: 6-13, 134: 1, 6-10.
Common varieties: None
Similar species: Surirella brebissonii (p. 146)
Surirella minuta (p. 147)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Very often associated with Surirella
brebissonii. S. angusta is generally distinguished from
S. minuta on the basis that it exhibits a lower degree of
heteropolarity. Recorded in both epipelic and epilithic
assemblages.
Fig. 129. Surirella angusta: (a) Aire River, VIC,
x1800; (b-c) Merri Creek, VIC, x 2300; (c) Merri
Creek, VIC, x1600.

146
Surirella brebissonii
Krammer & Lange-Bertalot 1987 (Figs 130a-c)
Synonyms: Refer to individual variety descriptions.
Description: Valve heteropolar, ovate (egg-shaped), one end broadly rounded, the other end narrower, but
also broadly rounded. Axial area narrow, somewhat undulate. Raphe canal located within a robust raised
wing that follows the circumference of the valve. Valve with prominent marginal ribs extending from
midway between the axial area and the valve margin, to the valve margins. Marginal ribs weakly radial in the
middle of the valve, becoming strongly radial at the valve ends. Transapical striae extremely fine (indistinct
under LM), located between coarse fibulae that extend to the apical axis. Length 17-30 (8-70) µm, width 11-
13 (8-30) µm, striae density 18-19 (17-19)/10 µm, marginal rib (3.5-7)density /10 µm.
Key references: Krammer & Lange-Bertalot 1988, p. 179, figs 123: 4, 5, 126: 2-11, 127: 1-13.
Common varieties:
var. brebissonii
Syn: Surirella ovata var. marina Brébisson in Rabenhorst 1887
Nominate variety, description as above.
var. kuetzingii Krammer & Lange-Bertalot 1987
Outline and fine construction of the valve is identical to the nominate variety. The division solely exists
on the basis of the smaller valve characteristics (Krammer & Lange-Bertalot, 1988).
Similar species: Surirella minuta (p. 147)
Surirella ovalis Brébisson 1838 (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 130. Surirella brebissonii: (a) Wimmera
River, VIC, x1750; (b) Glenelg River, VIC,
x1850; (c) Bremer River, SA, x1750.
Notes: Widespread and can be abundant. Probably the
most common of the Surirella species. Most
commonly recorded in epipelic and epilithic
assemblages.

147
Surirella minuta
Brébisson in Kützing 1849 (Figs 131)
Synonyms: Surirella pinnata W. Smith 1853
Surirella apiculata W. Smith 1856
Surirella salina W. Smith 1851.
Surirella ovata var. salina (W. Smith) Rabenhorst 1864
Surirella ovalis var. salina (W. Smith) Van Heurck 1896
Description: Valve regularly heteropolar, linear to linear-ovate with sharply pointed, apiculate ends. Valve
margins linear, convex or sometimes slightly concave in the middle. Axial area extremely narrow, linear.
Raphe canal located within the narrow, raised wing that follows the circumference of the valve. Valve with
prominent marginal ribs extending from the valve margins, almost to the axial area. Marginal ribs parallel in
the middle of the valve, becoming strongly radial towards the ends. Transapical striae extremely dense,
usually not distinguishable under LM, located between dense fibulae that extend to the apical axis. Length 30
(9-47) µm, width 10 (9-11) µm, striae density 22 (21-29)/10 µm, marginal rib density (6-8)/10 µm.
Key references: Krammer & Lange-Bertalot 1988, p. 186, figs 127: 14, 134: 2, 11, 12, 135: 1-14.
Common varieties: None
Similar species: Surirella angusta (p. 145)
Surirella brebissonii (p. 146)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread but rarely abundant. Broad
ecological tolerances, poor indicator species. S. minuta
is generally distinguished from S. angusta on the basis
that it exhibits a higher degree of heteropolarity. Found
in both epepelic and epilithic assemblages.
Fig. 131. Surirella minuta, Adelong River, NSW, x1850.

148
Genus Synedra
Key to the common species
1a. Valve with narrow, long tapering ends; striae density usually > 10/10 mm ........................ Synedra acus
1b. Valve with broadly rounded ends; striae density usually < 10/10 mm ............................... Synedra ulna
Synedra acus
Kützing 1844 (Figs 132a-b)
Synonyms: Fragilaria ulna var. acus (Kützing) Lange-Bertalot 1980
Synedra delicatissima W. Smith 1853
Description: Valve narrowly linear-lanceolate (needle-shaped), gradually tapering to capitate ends. Axial
area (pseudoraphe) narrowly lanceolate. Central area variable, often extending to the margins. Striae parallel.
Length 60-110 µm, width 3-5 µm, striae density 10-14(12)/10 µm.
Key references: Germain 1981, p. 78, pl. 27, figs 1-12.
John 1983, p. 55, pl. 12, fig. 15.
Krammer & Lange-Bertalot 1991, p. 144, figs 122: 11-13, 119: 8.
Patrick & Reimer 1966, p. 135, pl. 5, fig. 1.
Common varieties: None
Similar species: Ctenophora pulchella (p. 32)
Fragilaria capucina (p. 61)
Fragilaria tenera (not described in this guide)
Synedra ulna (p. 149)
Tabularia fasciculata (p. 152)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be moderately abundant.
Tolerates a broad range of pH and nutrient
concentrations. Mostly planktonic but can also be
epipelic and epilithic. Not chain forming.
Fig. 132. Synedra acus: (a-b) Barwon River,VIC, x1400.

149
Synedra ulna
(Nitzsch) Ehrenberg 1836 (Fig. 133)
Synonyms: Refer to individual variety descriptions.
Description: Valve linear to linear-lanceolate with drawn out rostrate, sub-apiculate to capitate ends. Axial
area (pseudoraphe) narrow and linear. Central area extremely variable from broadly rectangular to circular,
extending to the margins (sometimes with very short striae present), to completely absent. Transapical striae
parallel, conspicuously coarse and finely punctate, a feature that is not always visible under LM. Length 96-
263 (27-600) µm, width 7-7.5 (2-9) µm, striae density 9 (7-15)/10 µm.
Key references: Foged 1978, p. 133, pl. 8, figs 11-15, pl. 9, figs 1, 2, 14.
Germain 1981, p. 76, pl. 24, figs 1-7, pl. 168, fig. 8.
Holland & Clark 1989, p. 27, pl. 25, figs 5, 6, pl. 26, figs 1, 3-6.
John 1983, p. 61, pl. 26, figs 1-7.
Krammer & Lange-Bertalot 1991, p. 143, figs 119-122.
Patrick & Reimer 1966, p. 148, pl. 6, fig. 9, pl. 7, figs 1-10, pl. 8, figs 1, 2.
Thomas 1983, p. 76, pl. 4, fig. 1.
Common varieties:
var. ulna
Syn: Bacillaria ulna Nitzsch 1817
Frustulia splendens Kützing 1833
Synedra lanceolata Kützing 1844
Synedra splendens Kützing 1844
Nominate variety, description as above.
var. amphirhynchus (Ehrenberg) Grunow 1862
Syn: Synedra amphirhynchus Ehrenberg 1843
Synedra vitrea Bory ex Kützing 1844
Synedra ulna var. vitrea (Bory ex Kützing) Van Heurck 1885
Valve linear with sharp rostrate ends. No central area is present.
var. oxyrhynchus (Kützing) Van Heurck 1885
Syn: Synedra ulna var. medioconstricta Forti 1910
Valve < 100 µm length, transapical striae denser, around 15/10 µm.
Similar species: Ctenophora pulchella (p. 32)
Fragilaria capucina (p. 61)
Fragilaria tenera (not described in this guide)
Synedra acus (p. 148)
Synedra danica Kützing 1844 (not described in this guide)
Synedra ungeriana Grunow 1863 (not described in this guide)
Tabularia fasciculata (p. 152)

150
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 133. Synedra ulna, Ovens River, VIC,
x1300.
Notes: Widespread and can be moderately abundant.
Broad ecological tolerances. Mostly found in epipelic
and epilithic assemblages, but can also be planktonic.

151
Tabellaria flocculosa
(Roth) Kützing 1844 (Fig. 134)
Synonyms: Conferva flocculosa Roth 1797
Tabellaria fenestrata var. intermedia Grunow in Van Heurck 1881
Striatella flocculosa (Roth) Kuntze 1898
Description: Valve linear with notably inflated central region and swollen capitate ends. Axial area
(pseudoraphe) narrow, centrally widened to form a rhomboid central area. Transverse striae parallel to
slightly radial, irregularly spaced, and often visibly punctate. Multiple girdle bands may be present consisting
of either complete or incomplete septa which are visible at the valve ends. Cells often forming zig-zag
chains. Length 17-45 (6-130) µm, width 7-8 (3.8-8.5) µm, striae density 16 (13-20)/10 µm.
Key references: Foged 1978, p. 134, pl. 6, fig. 5.
Germain 1981, p. 50, pl. 12, figs 8-12.
Holland & Clark 1989, p. 27, pl. 26, fig. 7.
John 1983, p. 63, pl. 27, figs 1, 2.
Krammer & Lange-Bertalot 1991, p. 108, figs 106: 1-13, 107: 7, 11, 12.
Common varieties: None
Similar species: None
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be very abundant,
particularly in upland areas. Indicative of slightly
acidic, oligotrophic, low conductivity environments.
Girdle bands may initially be confused with valves.
Recorded in epipelic, epilithic and planktonic
assemblages.
Fig. 134. Tabellaria flocculosa, Kiewa River, VIC, x1600.

152
Tabularia fasciculata
(Agardh) Williams & Round 1986 (Fig. 135)
Synonyms: Diatoma fasciculatum Agardh 1812
Synedra fasciculata (Agardh) Kützing 1844
Fragilaria fasciculata (Agardh) Lange-Bertalot 1980
Description: Valve linear to linear-lanceolate. Valve ends vary between broadly rounded to elongated,
capitate or sub-rostrate ends. Axial area in the form of a pseudoraphe, which is linear to lanceolate in shape,
and between one third and one half of the valve width. Transapical striae conspicuously broad and parallel
throughout the entire valve. Length 25-140 (20-400)µm, width 3.9-5 (2-8)µm, striae density 12-17
(7.5-26)/10 µm.
Key references: Foged 1978, p. 132, pl. 8, figs 18, 20, pl. 9, fig. 5.
Germain 1981, p. 78, pl. 26, figs 5-10.
John 1983, p. 56, pl. 22, figs 6-14.
Krammer & Lange-Bertalot 1991, p. 150, figs 135: 1-18, 124: 3.
Patrick & Reimer 1966, p. 141, pl. 5, figs 17, 18.
Common varieties: None
Similar species: Synedra acus (p. 148)
Synedra ulna (p. 149)
Tabularia parva (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be very abundant. More
common in lowland sites. Can tolerate elevated
conductivity. Recorded in both epipelic and epilithic
assemblages.
Fig. 135. Tabularia fasciculata, Deep Creek, VIC, x1875.

153
Genus Tryblionella
Key to the common species
1a. Fibulae indistinguishable from the transapical striae ........................................... Tryblionella apiculata
1b. Fibulae distinguishable from the transapical striae ............................................................................... 2
2a. Striae easily distinguished ................................................................................ Tryblionella hungarica
2b. Striae extremely fine, difficult to distinguish ........................................................................................ 3
3a. Transapical 'costae' prominent ................................................................................. Tryblionella calida
3b. Valves small, less than 30 µm, transapical 'costae' visible only to one side .............. Tryblionella debilis
Tryblionella apiculata
Gregory 1857 (Fig. 136)
Synonyms: Synedra constricta Kützing 1844
Nitzschia constricta (Kützing) Ralfs in Pritchard 1861
Nitzschia apiculata (Gregory) Grunow 1878
Description: Valve broadly linear with concave to weakly constricted central margins. Valve ends cuneate,
with sharply rounded to short, subrostrate apices. Raphe canal very narrow and marginal. Fibulae
indistinguishable from the transapical striae, and although a central nodule is present, it is rarely visible
under LM. Striae prominent, parallel in the central region becoming slightly radial distally. Transapical striae
interrupted by a longitudinal fold that is of variable width and slightly eccentric. Length 35-42 (20-58) µm,
width 6-7 (4.5-8.5) µm, striae density 14-16 (15-20)/10 µm.
Key references: Germain 1981, p. 336, pl. 127, fig. 8.
Krammer & Lange-Bertalot 1988, p. 43, fig. 35: 1-6.
Common varieties: None
Similar species: Tryblionella hungarica (p. 156)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 136. Tryblionella apiculata, Wimmera
River, VIC, x1750.
Notes: Widespread and not usually abundant. Epipelic
and epilithic. May not be the correct name, which may
be Nitzschia constricta (Kutz) Ralfs in Pritchard,
according to IUCN rules, but it is a valid name. We use
it here to conform with the distinction between
Nitzschia and Tryblionella given in Gell et al 1999.
Mostly recorded in epipelic and epilithic assemblages.

154
Tryblionella calida
(Grunow in Cleve & Grunow) Mann 1990 (Figs 137a-b)
Synonyms: Nitzchia tryblionella var. calida (Grunow) Van Heurck 1885
Nitzschia umbilicata Hustedt 1949
Description: Valve broadly linear, slightly concave at the valve centre. Valve cuneate distally, with short
rostrate to sub-capitate ends. Raphe canal strongly marginal and with a slight constriction at the central
nodule. Fibulae apically enlongated, narrow. Valve surface with a longitudinal fold, and with prominent
transapical 'costae' that are parallel to slightly radial at the ends. Striae not usually visible. Length 32-33 (27-
70) µm, width 7 (8-11) µm, 'costae' density 18-20 (9-17)/10 µm, fibulae density (7-10)/10 µm.
Key references: Krammer & Lange-Bertalot 1988, p. 40, fig. 30: 1-5.
Common varieties: None
Similar species: Tryblionella apiculata (p. 153)
Tryblionella debilis (p. 155)
Tryblionella hungarica (p. 156)
Tryblionella levidensis (Fig. 137c) (not described in this guide)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be abundant. Most
commonly recorded in epipelic and epilithic
assemblages. Narrow nutrient and conductivity
tolerances.
Fig. 137. Tryblionella calida: (a-b) Deep Creek, VIC, x1700; Tryblionella levidensis, Dandenong Creek,
VIC, x2000.

155
Tryblionella debilis
Arnott in O'Meara 1873 (Figs 138a-d)
Synonyms: Nitzschia debilis (Arnott) Grunow in Cleve & Grunow non Pantocsek 1902
Nitzschia tryblionella var. debilis (Arnott) Hustedt 1913
Description: Valve relatively small (generally under 30 µm long), elliptical to broadly linear-elliptical, with
broadly rounded, cuneate ends. Raphe canal strongly marginal, fibulae small, rod-like, and with a central
nodule. Valve surface with a conspicuous longitudinal, eccentric fold, that appears as a clear hyaline line,
and with prominent transapical 'costae' that are visible only to one side. Transapical striae extremely fine,
indistinct under LM. Length 21-23 (13-26) µm, width 9-9.5 (7-10) µm, fibulae density (8-10)/10 µm.
Key references: Krammer & Lange-Bertalot 1988, p. 39, fig. 27: 9-11.
Common varieties: None
Similar species: Tryblionella calida (p. 154)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Notes: Widespread and can be moderately abundant.
Narrow pH tolerance. Recorded in both epipelic and
epilithic assemblages.
Fig. 138. Tryblionella debilis: (a-d) Dandenong Creek, VIC, x2100.

156
Tryblionella hungarica
(Grunow) Mann 1990 (Figs 139a-b)
Description: Valve linear with parallel to slightly concave margins, and with cuneate or apiculate, blunt
sub-rostrate ends. Raphe canal marginal and narrow. Fibulae small, rod-like, and with central two fibulae
widely spaced to form a central nodule. Transapical striae distinct, slightly radial distally. Valve surface with
a conspicous longitudinal, eccentric fold, that often appears as a distinct hyaline line. Length 38-78 (35-130)
µm, width 6-8 (5-9) µm, fibulae density 10 (7-10)/10 µm, striae density 17 (16-20)/10 µm.
Key references: Foged 1978, p. 106, pl. 45, fig. 10.
Germain 1981, p. 336, pl. 127, figs 1-7.
John 1983, p. 169, pl. 69, figs 11, 12.
Krammer & Lange-Bertalot 1988, p. 42, fig. 34: 1-3.
Common varieties: None
Synonyms: Nitzschia hungarica var. linearis Grunow in Cleve & Grunow 1880
Nitzschia hungarica Grunow 1962
Similar species: Tryblionella apiculata (p. 153)
Tryblionella calida (p. 154)
Tryblionella debilis (p. 155)
Ecological preferences:
TP
EC
pH
1 2 3 4 5
Fig. 139. Tryblionella hungarica: (a) Dandenong
Creek, VIC, x1800; (b) Bremer River, SA, x1750.
Notes: Widespread and can be moderately
abundant, particularly in saline streams. Narrow
pH and conductivity tolerances. Recorded in both
epipelic and epilithic assemblages.

157

158

157
GLOSSARY
µm Micrometre; 1000 micrometres = 1 millimetre
Aerophilous Able to live in marginal aquatic environments, for example, on moist surfaces or in the soil.
Apical axis The axis between the two poles of pennate diatoms. The axial area runs along the apical axis.
Araphid Term used to describe pennate diatom taxa lacking a raphe.
Arcuate Curved, arched.
Areola Regular repeated pores through the valve (or girdle). The pores are covered by a siliceous seive plate
with many fine perforations.
Axial area Area occupied by the raphe or pseudoraphe in pennate diatoms. In pseudoraphid valves, the axial
area may also known as the sternum.
Bifid/Bifurcate Divided into two parts, forked (e.g., a spine that is divided into two points)
Bipolar With two poles or ends.
Central area Region in the middle of the valve without striae, includes central nodule.
Central nodule Thickened region in the middle of the valve between the proximal raphe ends.
Centric Informal term referring to diatom taxa that exhibit radial symmetry in valve view (e.g., Melosira).
Circumneutral Preferring waters with pH valves close to 7.
Compound raphe Complex raphe, highly undulate along its length.
Connection cell Cell at which filament breaks, often denoted by spines or tube processes.
Convergent Term used to describe distal striae that are pointing towards the poles (i.e., in an opposite
direction to radially arranged striae).
Copulae See ‘Girdle”.
Costae Thickened internal ribs, usually visible under LM.
Cruciform Cross-shaped.
Cuneate Wedge-shaped.
DIC Differential Interference Contrast
Distal Term used to describe the polar regions of the valve (as opposed to ‘proximal’).
Dorsal side The most convex side of the valve for valves described as ‘dorsiventral’.
Dorsiventral - term used to describe pennate valves that are asymmetrical about the apical axis with sides of
different curvature (eg Eunotia, Cymbella, Encyonema, Amphora, Epithemia, Rhopalodia).
Eccentric Not centrally placed. For example, eccentric raphes are those that run from pole to pole but are
transapically displaced
Fascia An unornamented transverse strip located across the centre of the valve.
Fascicles Areolae arranged in rows, radiating from the centre of the valve face in centric diatoms.
Fibulae Struts that link the outer margins of the raphe canal in genera such as Nitzschia and Hantzschia.
Filiform Thread-like.
Foot pole The narrower of the two poles in a heteropolar valve.
Frustule collective term to describe the siliceous components of the diatom cell wall (hypovalve, epivalve,
girdle bands).
Fultoportulae Short tube-like structures extending internally and externally from the valve face. found in
several centric genera.
Girdle A series of siliceous bands that link the epi-and hypovalves of the frustule. Girdle bands are added
as the individual cell grows, causing the volume of the cell to increase in a single plane.
Head pole The broader of the two poles in a heteropolar valve.
Heteropolar Term used to describe pennate valves that are asymmetrical about the transapical axis. That is,
with differently shaped poles (e.g., Gomphonema, Asterionella, Meridion, Rhoicosphenia).
Hyaline area An area on the valve face that is without ornamentation (e.g., the absence of striae).
Intercalary bands See ‘girdle’.
Interfascicles The area between fascicles, often appearing as a thickened siliceous rib.
Isopolar Term used to describe pennate valves that are symmetrical to the apical axis.
Linear Valve with more or less parallel margins.
Lineolae Areolae in the shape of short lines rather than dots (punctae).
LM Light microscope.
Longitudinal furrow A furrow (narrow depression) adjacent to the raphe
Longitudinal line A narrow hyaline line interrupting the striae in a longitundanal (apical) direction.

158
Keel A thin section of the valve wall supporting the raphe canal in several genera (e.g., Entomoneis and
Surirella).
Mantle The portion of the valve extending away from the valve face to form a ‘skirt’ that meets the girdle
bands.
Medial Situated in the middle of the valve.
Naviculoid Term to describe valves with similar shapes to species within the genus Navicula.
Ocelli A clearly defined circular to elliptical area, usually near the valve margin covered by distinctly
smaller pores (termed ‘porelli’). Often seen as smooth in LM (cf. Pleurosira).
Pennate Informal term referring to diatoms that exhibit a form of symmetry other than radial (usually
bilateral).
Periphytic: A term describing plant (including algal)species that grow upon other surfaces. This includes
species that are: epiphytic (which grow upon plants), epilithic (which grow upon rocks), epipsammic (which
grow upon sand), and epipelic (which grow upon mud/silt)
Pervalvar striae Striae ornamenting the sides of cylindrically shaped centric diatoms.
Proximal Term used to describe the the middle region of the valve (as opposed to distal).
Pseudoraphe A clear area forming a longitudinal line along the apical axis in the absence of a raphe.
Puncta Small pore-like structures on the valve face, usually extending to the mantle; frequently arranged in
lines (striae -see below) across the valve face.
Raphe A canal (slit-like structure) that runs for a varying distance along the apical axis of the valves of
many diatom genera. It is believed to facilitate the movement of diatom cells through the secretion of
mucilage.
Reverse-lateral A raphe that appears to cross over itself towards the proximal region.
Ribs A line of thickened silica often slightly raised above the valve surface.
Septum An internal plate extending from the girdle into the interior the valve.
Sinuous Undulate.
Sternum A thickened and sometimes raised area running along the apical axis of pennate valves.
Stigma An enlarged pore found adjactent to the central nodule in some genera (e.g., Cymbella and
Gomphonema).
Striae Lines formed by the linear arrangement of punctae across the valve.
Sulcus Furrow (indentation) running around the valve margin of several species of Aulacoseira.
Transapical The plane that is perpendicular to the apical (longitudinal) plane.
Transverse Extending across the valve along the transapical plane.
Valve The upper (epivalve) or lower (hypovalve) portion of the diatom frustule excluding the girdle bands.
Ventral side The least convex of the valve for valves described as ‘dorsiventral’. May be concave, straight
or convex (but always less convex than the dorsal side).
Vestigial raphe A very short raphe, often considered rudimentary (e.g., Eunotia).

159
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161
TAXONOMIC INDEX
Species described in this guide appear in normal type-face, all other species names (synonyms and similar species) are
italicised.
Achnanthes andicola 7
Achnanthes clevei 12
Var. rostrata 12
Achnanthes conspicua 8
Achnanthes delicatula 13
spp hauckiana 13
Achnanthes exigua 6,
var. constricta 6
var. exigua 6
var. heterovalva 6
Achnanthes fonticola 13
Achnanthes hauckiana 13
Achnanthes hungarica 7, 9, 11, 16
Achnanthes lanceolata 15
var. dubia f. minuta 14
var. frequentissima 14
Achnanthes linearis
var. pusilla 16
Achnanthes microcephala
f. scotica 10
Achnanthes minutissima
var. inconspicua 10
var. scotica 10
var. cryptocephala 10
Achnanthes oblongella 8
Achnanthes pseudohungarica 7
Achnanthes pusilla 16
Achnanthes strenzki 10
Achnanthes cf. subexigua 6, 9, 11
Achnanthidium affine 11
Achnanthidium altergracillima 11
Achnanthidium clevei 12
var. rostratum 12
Achnanthidium delicatulum 13
Achnanthidium hungaricum 7
Achnanthidium lanceolatum 15
Achnanthidium lineare 10
Achnanthidium microcephalum 10
Achnanthidium minutissimum 7, 9, 10, 16, 42, 136
var. ‘inconspincua’ 10
var. ‘scotica’ 10
Achnanthidium pusillum 16
Achnanthidium saprophila 11
Actinocyclis normanii 17
var. subsalsus 17
Amphicampa mirabilis 58
Amphiprora alata 48
Amphiprora costata 49
Amphiprora hustedtii 49
Amphiprora paludosa 50
Amphora acutiscula 19
Amphora affinis 20
Amphora atomus 87
Amphora coffeaeformis 18, 22
var. acutiscula 19
var. borealis 19
Amphora gouwsii 22
Amphora libyca 20
Amphora ovalis
var. affinis 20
var. libyca 20
var. pediculus 20, 21
Amphora pediculus 20, 21
Amphora perpusilla 21
Amphora salina 19
Amphora veneta 19, 21, 22
Aulacoseira ambigua 23, 25, 26
Aulacoseira crenulata 23
Aulacoseira granulata 23, 24, 26
var. angustissima 25
Aulacoseira italica 23, 25, 26
ssp. subartica 23, 26
Aulacoseira subartica 25, 26
f. subborealis 26
Aulacoseira valida 23
Bacillaria cistula 40
Bacillaria paradoxa 27
Bacillaria paxillifer 27
Bacillaria ulna 149
Brebissonia vulgaris 66
Ceratoneis lunaris 54
Cocconeis elongata 28
Cocconeis euglypta 28
Cocconeis lineata 28
Cocconeis placentula 28
var. euglypta 28
var. lineata 28
Cocconeis pumila 28
Cocconeis punctata 28
Cocconema gracile 45
Cocconema tumidum 41
Colletonema viridulum 64
Conferva flocculosa 151
Coscinodiscus normanii 17
Coscinodiscus rothii
var. subsalsum 17
Coscinodiscus subsalsus 17
Coscinodiscus subtilis
var. fluviatilis 17
Craticula accomoda 30, 31, 85, 91, 95
Craticula cuspidata 31
Craticula halophila 30, 31, 91, 95
Ctenophora pulchella 32, 148, 149
Cyclostephanous invisitatus 34
Cyclostephanous tholiformis 33, 34, 35
Cyclotella kuetzingiana 36
Cyclotella meneghiniana 36, 38
var. stellifera 38
var. stelligera 38
var. stellullifera 38
Cyclotella pseudostelligera 36, 37, 38
Cyclotella rectangula 36
Cyclotella stelligera 36, 37, 38
Cyclotella tasmanica 38
Cymbella abnormis 131
Cymbella cistula 40, 41
Cymbella gracilis 45
Cymbella lunata 45
Cymbella maculata 40
Cymbella microcephala 42
Cymbella minuta 46
var. silesiaca 47
Cymbella pediculus 21
Cymbella pusilla 43

162
Cymbella ruttnerii 42
Cymbella scotica 45
Cymbella sinuata 131
Cymbella stomatophora 41
Cymbella tumida 40, 41
Cymbella ventricosa 46, 47
Cystopleura sorex 53
Cystopleura zebra 51
var. porcellus 51
var. proboscidea 52
var. saxonica 52
Diatoma elongatum 44
Diatoma fasciculatum 152
Diatoma mesoleptum 44
Diatoma moniliformis 44
Diatoma tenuis 44
var. elongatum 44
Diploneis hudsonis 59
Encyonema gracile 43, 45, 47
Encyonema mesiana 45
Encyonema minutum 45, 46, 47
Encyonema silesiacum 45, 46, 47
Encyonopsis microcephala 42
Entomoneis alata 48, 49, 50
Entomoneis costata 48, 49, 50
Entomoneis paludosa 48, 49, 50
Eolimna minima 9, 136, 138
Eolimna subminuscula 85, 136, 138
Epithema saxonica 52
Epithemia adnata 51, 53
var. minor 51
var. porcellus 51
var. probiscidea 51
var. saxonica 51
Epithemia gibba 134
Epithemia musculus 135
Epithemia porcellus 51
Epithemia proboscidea 52
Epithemia saxonica 52
Epithemia sorex 52, 53
Epithemia ventricosa 134
Epithemia zebra 51
var. minor 51
var. porcellus 51
var. proboscidea 52
var. saxonica 52
Eunotia amphioxys 80
Eunotia bilunaris 54, 57
var. linearis 54
var. mucophila 54
Eunotia circumborealis 57
Eunotia curvata
var. linearis 54
Eunotia eruca 58
Eunotia exigua 56
var. bidens 56
var. undulata 56
var. tridentula 56
Eunotia flexuosa
var. linearis 54
Eunotia implicata 57
Eunotia impressa
var. angusta 57
Eunotia intermedia 57
Eunotia lunaris 54
var. subarcuata 54
Eunotia minor 57
Eunotia naegelii 55
Eunotia okavangoi 54
Eunotia paludosa 56
Eunotia pectinalis
var. minor 57
Eunotia serpentina 58
Eunotia soleirolii 57
Eunotia subarcuata 54
Exilaria curvata 54
Exilaria pulchella 32
Exilaria vaucheriae 62
Fallacia pygmaea 59, 60
Fallacia tenera 59, 60
Fragilaria aequalis 63
Fragilaria binodis 142
Fragilaria brevistriata 130
var. capitata 130
var. inflata 130
var. pusilla 130
var. subacuta 130
var. subcapitata 130
Fragilaria capucina 32, 61, 148, 149
var. distans 62
var. gracilis 61
var. lanceolata 61
var. mesolepta 61
var. rumpens 62
var. vaucheriae 62
Fragilaria construens
f. binodis 142
f. construens 141
f. exigua 142
f. subsalina 141
f. venter 141
var. binodis 142
var. exigua 142
var. pumila 141
var. subsalina 141
var. venter 141
Fragilaria elliptica 143
Fragilaria exigua 142
Fragilaria fasciculata 152
Fragilaria gracilis 61
Fragilaria inflata 130
Fragilaria intermedia 62
Fragilaria mesolepta 61
Fragilaria mutabile 143
var. intercedens 143
Fragilaria pinnata 143
var. intercedens 143
Fragilaria pulchella 32
Fragilaria pseudolaevissima 62
Fragilaria subconstricta 61
Fragilaria tenera 148, 149
Fragilaria tenuistriata 61
Fragilaria ulna
var. acus 148
Fragilaria vaucheriae 62
Fragilaria venter 141
Fragilaria virescens 63
Fragilariforma virescens 63
Frustulia acuminata 77
Frustulia adnata 51
Frustulia attenuata 78
Frustulia coffeaeformis 19
Frustulia lanceolata 93
Frustulia rhomboides 64, 66
var. amphipleuroides 64
var. saxonica 64
var. viridula 64
Frustulia saxonica 64

163
Frustulia silesiaca 102
Frustulia splendens 149
Frustulia vulgaris 65, 66
var. capitata 66
Gallionella decussata 25
Gallionella granulata 25
Gallionella varians 83
Gomphonema abbreviatum 132
Gomphonema acuminatum 68
Gomphonema affine 69, 70, 72
Gomphonema amoenum 72
Gomphonema angustum 70, 74
Gomphonema augur 75
Gomphonema bohemicum 70
Gomphonema brebissonii 68
Gomphonema capitatum 76
Gomphonema clavatum 69, 70, 71, 72, 74, 76
Gomphonema commutatum 71
Gomphonema constrictum 76
var. subcapitata 76
Gomphonema coronatum 68
Gomphonema curvatum 132
Gomphonema dichotomum 70
Gomphonema fanensis 70
Gomphonema gracile 69, 72, 75
Gomphonema grunowii 72
Gomphonema insigne 72
Gomphonema intricatum 70
Gomphonema lagenula 73, 74
Gomphonema lanceolatum 69, 72
Gomphonema longiceps 71
Gomphonema micropus 74
Gomphonema montanum 71
Gomphonema mustela 71
Gomphonema obliqua 71
Gomphonema parvulum 69, 70, 71, 72, 73, 74, 75
var. lagenula 73
Gomphonema pseudoaugur 75
Gomphonema pumilum 70
Gomphonema subclavatum 71
Gomphonema truncatum 76
var. capitatum 76
var. turgidum 76
Gomphonema turgidum 76
Gyrosigma acuminatum 77, 78, 79
Gyrosigma attenuatum 77, 78, 79
Gyrosigma kutzingii 79
Gyrosigma spencerii 77, 78, 79
Hantzschia abundans 80
Hantzschia amphioxys 80, 124
Himantidium exiguim 56
Himantidium minus 57
Hippodonta capitata 86, 126
Homoeocladia bulnheimiana 112
Homoeocladia conferta 111
Homoeocladia filiformis 111
Homoeocladia germanica 111
Karayevia clevei 12
var. ‘rostrata’ 12
Luticola goeppertiana 81, 82
Luticola mutica 81, 82
var. ventricosa 82
Mayamaea atomus 87, 136
var. permitis 87
var. excelsa 87
Melosira ambigua 23
Melosira crenulata
var. ambigua 23
Melosira granulata 25
var. angustissima 25
Melosira italica
ssp. subartica 26
Melosira lineolata 25
Melosira varians 83
Navicella pusilla 43, 45
Navicula accomoda 30
Navicula acuminata 77
Navicula alata 48
Navicula amphiceros 98
Navicula atomoides 136
Navicula atomus 87
Navicula auriculata 60
Navicula avenacea 93
Navicula biseriata 60
Navicula borealis 126
Navicula brauniana 127
Navicula braunii 127
Navicula bremensis 93
Navicula caduca 87
Navicula capitata 86
Navicula capitatoradiata 88
Navicula cari
var. recens 97
Navicula cincta
var. leptocephala 90
Navicula cocconeiformis 28
Navicula cryptocephala 88, 90, 92, 94, 96, 98, 99, 100, 101,
102
var. exilis 88
var. subsalina 101
var. veneta 101
Navicula cryptotenella 88, 89, 92, 95, 96, 100
Navicula cuspidata
var. halophila 31
Navicula demissa 85
Navicula dissipata 60
Navicula erifugia 90, 97, 99
Navicula excelsa 87
Navicula exilis 88
Navicula fluens 95
Navicula frugalis 85
Navicula geoppertiana 81
Navicula germainii 102
Navicula gibba 134
Navicula gondwana 96
Navicula gregalis 91
Navicula gregaria 30, 31, 91, 101
Navicula halophila 31
Navicula hariola 95
Navicula heimansioides 92, 96
Navicula heurflerii
var. leptocephala 90
Navicula humilis 86
Navicula hungarica
var. capitata 86
Navicula imbricata 82
Navicula incerta 93
Navicula incertata 93, 101
Navicula incompta 42
var. dissipatoides 60
Navicula lanceolata 93, 97, 99, 102
Navicula leptocephala 90
Navicula luzonensis 85
Navicula menisculus 89, 94, 97
var. upsaliensis 95
Navicula minima 136
Navicula minutissima 136
Navicula minutula 59

164
Navicula molestiformis 30, 31, 85, 95
Navicula mutica 82
var. goeppertiana 81
Navicula neoventricosa 82
Navicula peratomus 86
Navicula perminuta 93
Navicula permitis 86
Navicula pseudoatomus 86
Navicula pseudoscutiformis 28
Navicula pupula 137
Navicula pygmaea 59
Navicula radiosa 88, 94, 96
var. acuta 96
var. parva 92, 96
var. tenella 89
Navicula recens 97, 99
Navicula rhomboides 64
var. amphipleuroides 64
Navicula rhynchocephala 88, 97, 102
var. amphiceros 97
Navicula rhynchotenella 98
Navicula rostellata 102
Navicula salinarum 98
Navicula schroeterii 90, 99
var. escambia 99
Navicula seminulum 138
Navicula simulata 99
Navicula spencerii 79
Navicula strenzkei 10
Navicula subcapitata
var. paucistriata 128
Navicula subminuscula 85
Navicula submuralis 138
Navicula symmetrica 99
Navicula tantula 136
Navicula tenella 89
Navicula tenelloides 100
Navicula tenera 60
Navicula terminata 81
Navicula twymaniana 95
Navicula umbonata 124
Navicula uniseriata 60
Navicula veneta 88, 90, 95, 100, 101
Navicula viridula 90, 94, 98, 99, 101
var. germanii 102
var. rostellata 102
Navicula zebra 51
Nitzschia abbreviata 114
Nitzschia accedens 111
Nitzschia accommodata 119
Nitzschia acicularis 104
Nitzschia acidoclinata 112, 120
Nitzschia adamata 123
Nitzschia agnita 105, 115, 119
Nitzschia alexandrina 106
Nitzschia allansonii 107
Nitzschia amphibia 85
Nitzschia angustata 63
Nitzschia apiculata 153
Nitzschia aurariae 106
Nitzschia bacillum 115, 120
Nitzschia balcanica 107
Nitzschia barvarica 121
Nitzschia capensis 105
Nitzschia capitellata 107, 117, 119, 123, 124
Nitzschia clausii 108
Nitzschia conferta 111
Nitzschia constricta 153
Nitzschia debilis 155
Nitzschia deserta 107
Nitzschia desertorum 109, 118
Nitzschia diducta 124
Nitzschia dissipata 27, 110, 121
var. media 110
Nitzschia draveillensis 104
Nitzschia elegantula 118
Nitzschia elliptica
var. alexandrina 106
Nitzschia fasciculata 111
Nitzschia filiformis 111, 117, 122
var. conferta 108, 111
Nitzschia fossalis 124
Nitzschia frequens 107
Nitzschia frustulum 112, 114, 116, 120
var. inconspicua 114
var. tenella 120
Nitzschia gandersheimiensis 123
Nitzschia garrensis 121
Nitzschia graciliformis 113
Nitzschia gracilis 104, 105, 113
Nitzschia graciloides 113
Nitzschia hantzschiana 109
Nitzschia hiemalis 120
Nitzschia hungarica 156
var. linearis 156
Nitzschia inconspicua 112, 114
Nitzschia intermedia 107, 117, 119
Nitzschia invisitata 114
Nitzschia irremissa 105
Nitzschia kuetzingioides 105
Nitzschia lacuum 105, 115, 118, 120
Nitzschia liebetruthii 112, 116, 120
var. major 116
var. siamensis 112
Nitzschia linearis 117
var. subtilis 117
var. tenuis 117
Nitzschia manca 107
Nitzschia media 110, 121
Nitzschia microcephala 118
Nitzschia minutissima 112
Nitzschia minutula 120
Nitzschia obtusa 108
Nitzschia palea 105, 107, 109, 111, 113, 119, 120, 123
f. major 119
var. debilis 119
var. perminuta 120
var. tenuirostris 119
Nitzschia paradoxa 27
Nitzschia perminuta 120
Nitzschia perpusilla 114, 116
Nitzschia pilum 119
Nitzschia pusilla 106
Nitzschia quadrangula 112
Nitzschia recta 110, 117, 121, 123
Nitzschia rectiformis 121
Nitzschia salincola 107
Nitzschia sigma 117, 122
var. clausii 108
var. curvata 108
Nitzschia solita 109
Nitzschia stagnorum 124
Nitzschia subcapitella 107
Nitzschia subfrequens 107
Nitzschia subtilis 117
Nitzschia supralitorea 116
Nitzschia tenuis 117
Nitzschia thermalis 124

165
Nitzschia tryblionella
var. calida 154
var. debilis 155
Nitzschia tubicola 107, 123
Nitzschia umbilicata 154
Nitzschia umbonata 124
Odontidium mutabile 143
Orthosira punctata 25
Pinnularia amphicephala 127
Pinnularia borealis 86, 126
var. rectangularis 126
var. scalaris 126
var. thuringiaca 126
var. undulata 126
Pinnularia brauniana 127
Pinnularia braunii 127
var. amphicephala 127
Pinnularia hilseana 128
Pinnularia lata
var. rabenhorstii 126
f. thuringaca 126
Pinnularia streptoraphe
var. minor 129
Pinnularia subcapitata 128
var. paucistriata 128
var. stauroneiformis 128
Pinnularia viridiformis 129
Planothidium delicatulum 13, 15
spp. haukiana 13
Planothidium frequentissimum 14, 15
Planothidium lanceolatum 13, 14, 15
Pleurosigma acuminatum 77
Pleurosigma attenuatum 78
Pleurosigma gracilentum 79
Pleurosigma kutzingii 79
Pleurosigma spencerii 79
Pseudostaurosira brevistriata 130, 142, 143
var. ‘capitata’ 130
var. ‘inflata’ 130
Reimeria sinuata 131
Rhoicosphenia abbreviata 132
Rhoicosphenia curvata 132
Rhopalodia acuminata 133
Rhopalodia brebissonii 133, 134, 135
Rhopalodia gibba 133, 134, 135
var. parallela 134
Rhopalodia gibberula 133
var. musculus 135
Rhopalodia musculus 133, 134, 135
var. succinta 133
Rhopalodia operculata 133
Rhopalodia parallela 134
Rhopalodia ventricosa 134
Rossithidium pusillum 7, 11, 16
Schizonema thwaitesii 93
Schizonema vulgare 66
Sellaphora bacillum 137
Sellaphora laevissima 137
Sellaphora mutata 137
Sellaphora pseudopupula 137
Sellaphora pupula 137
var. capitata 137
Sellaphora seminulum 7, 136, 137, 138
var. hustedtii 138
var. intermedia 138
Sphenella parvula 74
Stauroneis goeppertiana 81, 82
Stauroneis rectangularis 137
Stauroneis rotaeana 82
Stauroneis salina 139
Stauroneis ventricosa 82
Stauroneis wislouchii 140
Staurophora salina 139, 140
Staurophora wislouchii 139, 140
Staurosira construens 130, 141, 143
f. binodis 142
f. construens 141
f. venter 141
f. exigua 142
var. subsalina 141
Staurosira elliptica 142, 143
Staurosira intermedia 62
Staurosirella leptostauron 143
Staurosirella pinnata 142, 143
var. intercedens 130, 143
Stephanodiscus hantzschianus 34
Stephanodiscus hantzschii 34, 35
f. parva 35
Stephanodiscus minutulus 33, 35
Stephanodiscus parvus 33, 34, 35
Stephanodiscus pusillus 34
Stephanodiscus zachariasii 34
Striatella flocculosa 151
Surirella angusta 145, 147
Surirella angustata 145
Surirella apiculata 147
Surirella brebissonii 145, 146, 147
var. kuetzingii 146
Surirella melosiroides 36
Surirella minuta 145, 146, 147
Surirella ovalis 146
var. salina 147
Surirella ovata
var. marina 146
var. salina 147
Surirella pinnata 147
Surirella salina 147
Surirella thermalis 124
Synedra acicularis 104
Synedra acus 32, 62, 148, 149, 152
Synedra amphirhynchus 149
Synedra atomus 87
Synedra bilunaris 54
Synedra constricta 153
Synedra danica 149
Synedra debilis 119
Synedra delicatissima 148
Synedra dissipata 110
Synedra famelica 61
Synedra familiaris 32, 61
Synedra fasciculata 152
Synedra frustulum 112
Synedra lanceolata 149
Synedra lunaris 54
var. subartica 54
Synedra minutissima 112
Synedra perpusilla 112
Synedra pulchella 32
Synedra quadrangula 112
Synedra rumpens 62
var. familiaris f. major 61
var. meneghiniana 62
Synedra sigma 122
Synedra splendens 149
Synedra ulna 32, 62, 148, 149, 152
var. amphirhynchus 149
var. medioconstricta 149
var. oxyrhynchus 149

166
var. vitrea 149
Synedra ungeriana 149
Synedra vaucheriae
var. distans 62
Synedra vitrea 149
Tabellaria fenestrata
var. intermedia 151
Tabellaria flocculosa 151
Tabularia fasciculata 148, 149
Tabularia parva 152
Triceratium exiguum 142
Tryblionella apiculata 124, 153, 154, 156
Tryblionella calida 154, 155, 156
Tryblionella debilis 154, 155, 156
Tryblionella hungarica 124, 153, 154, 156
Tryblionella levidensis 154
Vanheurckia rhomboides 64
Vanheurckia vulgaris 66
Vibrio paxillifer 27