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Accepted by J. Sparks: 16 Jul. 2012; published: 31 Aug. 2012
ZOOTAXA
ISSN 1175-5326 (print edition)
ISSN
1175-5334 (online edition)
Copyright © 2012 · Magnolia Press
Zootaxa 3447: 41–55 (2012)
www.mapress.com
/zootaxa/
Article
41
Microgobius urraca (Teleostei: Gobiidae), a new species of goby from the tropical
eastern Pacific
LUKE TORNABENE
1
, JAMES L. VAN TASSELL
2
& D. ROSS ROBERTSON
3
1
Texas A&M University – Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78418, U.S.A. E-mail: Luke.Tornabene@tamucc.edu
2
Department of Ichthyology, American Museum of Natural History, New York, New York 11024, U.S.A.
E-mail: jvantassell@gobiidae.com
3
Smithsonian Tropical Research Institute, Balboa, Panam, Republic of Panama. E-mail: drr@stri.org
Abstract
A new species of goby in the genus Microgobius (Teleostei: Gobiidae: Gobiosomatini) is described from the Pacific coast
of Panama. It is morphologically similar to M. erectus, but differs from that species in possessing fewer lateral scale rows,
lacking a patch of ctenoid scales under the pectoral fin, having unpigmented epaxial myosepta, having a distinct oval-
shaped dark blotch on the first dorsal fin, and possessing three blue-white stripes on a dark caudal fin. Differences in both
the number and type of scales, dorsal and anal fin ray counts, the poor development of a fleshy dorsal crest, and overall
color patterns further distinguish this species from the remaining eastern Pacific congeners. Photographs of all Pacific
species of Microgobius and a dichotomous key to the Pacific members of the genus are provided.
Key words: Gobiosomatini, Microgobius group, Gobiiformes, Panama, American seven-spined gobies
Introduction
Microgobius Poey 1876 is a genus of American seven-spined gobies (tribe Gobiosomatini) that currently includes
six species from tropical and warm temperate waters in the western Atlantic and eight species in the tropical
eastern Pacific. Western Atlantic species include Microgobius carri Fowler 1945, M. gulosus (Girard 1858), M.
meeki Evermann and Marsh 1899, M. microlepis Longley and Hildebrand 1940, M. signatus Poey 1876, and M.
thalassinus (Jordan and Gilbert 1883), while M. brevispinis Ginsburg 1939, M. crocatus Birdsong 1968, M. curtus
Ginsburg 1939, M. cyclolepis Gilbert 1890, M. emblematicus (Jordan and Gilbert 1882), M. erectus Ginsburg 1938,
M. miraflorensis Gilbert and Starks 1904, and M. tabogensis Meek and Hildebrand 1928 are restricted to the
eastern Pacific. Species of Microgobius often have bright color patterns in life that feature silvery bodies with
irisdescent blue, green, red and yellow marks on the head, body or median fins. Sexual dimorphism in color
patterns, cranial osteology, dorsal fin spines, and the development of a fleshy dorsal crest occurs in several species.
Most species of Microgobius are found associated with fine sediments in estuaries and shallow coastal waters while
some are associated with burrows, roots and open sandy areas. Several species are common in depths less than 1 m
whereas other species reach depths of at least 57 m (Birdsong 1981; Robertson and Allen 2008).
The genus was last treated in its entirety in a taxonomic review by Birdsong (1981). Several subsequent studies
have addressed the relationship of Microgobius to other gobiid genera. Birdsong et al. (1988) placed the genus in
the Microgobius group of the Gobiosomatini, together with Bollmannia, Parrella and Palatogobius. This was
based on shared pterygiophore insertion patterns, vertebral counts, the presence of one epural and the absence of
fusion of hypural 1–2 with 3–4 and the terminal caudal element. Akko and Antilligobius have since been added to
the Microgobius group based on both molecular and morphological data (Ruber et al. 2003; Van Tassell and
Baldwin 2004; Van Tassell et al. 2012). A clear sister genus to Microgobius has yet to be established. Monophyly
of Microgobius, of the Microgobius group, and of the tribe Gobiosomatini is strongly supported by recent
molecular phylogenetic analyses (Rüber et al. 2003; Thacker and Roje 2011).
TORNABENE ET AL.
42 · Zootaxa 3447 © 2012 Magnolia Press
In 2003, during a cruise of the Smithsonian Tropical Research Institute’s research vessel R/V Urraca, three
large gobies were collected while trawling on sand and leaf-litter bottoms at depths of 12–20 m off the Pacific coast
of western Panama. The specimens were identified as a species of Microgobius based on the following suite of
characters: first dorsal fin with seven spines; pterygiophore formula 3(221110) (following Birdsong et al. 1988);
second dorsal and anal fin well separated from caudal fin; caudal fin lanceolate; head and body laterally
compressed; pelvic fins fused into a disc, the frenum of which has a smooth posterior margin; trunk of body scaled;
and head, nape, breast and pectoral fin base without scales. Based on several prominent differences between these
three specimens of Microgobius and the eight previously described species of Microgobius from the eastern Pacific
we describe them as a new species. We comment on the phylogenetic relationships of the genus and provide
photographs and a dichotomous key for the Pacific species of Microgobius.
Methods
Methods for counts and measurements follow Van Tassell et al. (2012). The dorsal pterygiophore formula is that of
Birdsong et al. (1988), patterns of sensory papillae are described according to Miller (1986) and terminology of the
head-canal pores follows Akihito et al. (1984). Institutional acronyms follow Sabaj Pérez (2010). Counts of
branched and segmented caudal fin rays and vertebrae were made from radiographs.
Microgobius urraca sp. nov.
Dark-finned sand goby
(Figures 1,2)
Material examined: Holotype: AMNH 255033, field number JVT-03-238, 69.4 mm SL, female, east of Isla Raya,
Panama (Pacific), 7.3966
o
, -80.2991
o
, trawled specimen, collected by J.L. Van Tassell and D.R. Robertson, R/V
Urraca, 20 June 2003, 12 m, sand substrate.
Paratypes: AMNH 255034, field number JVT-03-208, GenBank accession number JX139737 (partial
cytochrome c oxidase I sequence), 62.2 mm SL, male, north of Isla Secas near main land, Panama (Pacific),
8.1435
o
, -81.8775
o
, trawled specimen, collected by J.L. Van Tassell and D.R. Robertson, R/V Urraca, 16 June
2003, 15-18 m, sand and leaf litter substrate; USNM 404510, field number JVT-03-210, 59.8 mm SL, male, north
of Islas Secas, Panama (Pacific), 8.1135
o
, -81.8336
o
, trawled specimen, collected by J.L. Van Tassell and D.R.
Robertson, R/V Urraca, 16 June 2003, 20 m, sand and leaf litter substrate.
Diagnosis. The new species is morphologically similar to M. erectus, but differs from that species in
possessing fewer lateral scale rows, lacking a patch of ctenoid scales under the pectoral fin, having unpigmented
epaxial myosepta, a distinct oval-shaped dark blotch on the first dorsal fin, and possessing three blue-white stripes
on a dark caudal fin. Differences in both the number and type of scales, dorsal and anal fin ray counts, the poor
development of a fleshy dorsal crest, and overall color pattern further distinguish this species from the remaining
eastern Pacific congeners.
Description. Morphometric data and summary of meristics given in Table 1. Counts of the holotype indicated
by an asterisk, followed by number of specimens with each count in parentheses.
Median and paired fins: first dorsal VII*(3); first dorsal spines not highly filamentous, free tips of spines
extending only a short distance beyond interspinal membrane; second dorsal I,14*(3); anal I,14*(3); second dorsal
and anal fin rays extending slightly posterior to origin of caudal fin rays when laid flat; pectoral rays 21(1), 22*(1),
23(1); pectoral fin length 17.3–20.2 % SL; caudal fin long and lanceolate, 35.3–40.0 % SL; segmented caudal rays
17*(2); branched caudal rays 15*(2); pelvic fin I,5*(3); pelvic fins united to form oval-shaped disk with well-
developed frenum; pelvic frenum with smooth posterior margin.
Scales: trunk covered with cycloid scales; predorsal region, cheek, operculum, pectoral fin base and pelvic fin
base without scales; pre-anal region with small embedded cycloid scales; scales on anterior and ventral portions of
trunk small, partially imbedded, and in irregular rows, becoming larger and arranged in distinct rows dorsally and
posteriorly; no small patch of ctenoid scales beneath pectoral fin; lateral scale rows 67*(1), 75(1), 76(1); transverse
scale rows 15*(1), 17(1), 18 (1).
Zootaxa 3447 © 2012 Magnolia Press · 43
NEW MICROGOBIUS SPECIES FROM THE TROPICAL EASTERN PACIFIC
ABLE 1. Microgobius urraca morphometrics and counts. Measurements are in % SL.
Head: head length 22.1–23.3 % SL; mouth angled upwards at approximately 45–55 from horizontal; upper jaw
length 10.2–12.9 % SL; teeth in upper jaw in two to three rows near symphysis, becoming two distinct rows near
midpoint of premaxilla, terminating as single row near end of upper jaw; teeth in lower jaw two to three rows
anteriorly near symphysis, becoming a single row near midway of dentary; teeth in outer row of both jaws
enlarged, elongate and with slightly curved canines; tongue bilobed with deep medial notch; eye diameter 6.1–6.3
% SL; interorbital width 3.2–3.7 % SL; snout short, 4.7–5.9 % SL; low fleshy dorsal crest anterior to first dorsal fin
in both sexes; anterior nare on short erect tube; posterior nare small, adjacent to head pore B’; gill rakers 5+16;
epibranchials present.
Genitalia: female papillae unpigmented, short and bulbous; papilla in males unpigmented, slightly elongate
and conical.
Sensory papillae and head pores (Figure 2): two interorbital canals anteriorly, joining posteriorly to become
single interorbital canal at point in line with midpoint of eye; oculoscapular pores B’, D(s), F, G, H’ present;
posterior canal (typically between pores K’ and L’) absent; preopercular pores M’, O’ present; sensory papillae on
head in transverse pattern with three vertical rows below eye; transverse papillae row b beginning at vertical
through midpoint of pupil, extending posteriorly, ending well short of posterior margin of preopercle; transverse
papillae row d long, beginning anterior one third ofeye, extending posteriorly, ending well short of posterior margin
Holotype Paratype Paratype
Catalog Number AMNH 255033 AMNH 255034 USNM 404510
Field number JVT-03-238 JVT-03-208 JVT-03-210
Sex female male male
SL (mm) 69.4 62.2 59.8
Eye diameter 6.23 6.27 6.05
Upper jaw length 10.2 12.86 12.2
Head length 22.1 23.33 22.4
Post orbital length 10.95 10.93 11.2
Depth at DI origin 15.85 15.51 16.3
Least caudal peduncle depth 8.07 8.84 7.85
Pectoral fin length 18.7 17.25 20.2
Caudal fin length 35.3 38.7 40
Snout length 4.7 5.86 5.2
Interorbital width 3.2 3.4 3.7
Dorsal crest present present present
Precaudal vertebrae 11 11 11
Caudal vertebrae 16 16 16
First dorsal fin VII VII VII
Second dorsal fin I,14 I,14 I,14
Anal fin I,14 I,14 I,14
Caudal fin, segmented rays 17 17 x
Caudal fin, branched rays 15 15 x
Pectoral fin 22 21 23
Pelvic fin I,5 I,5 I,5
Transverse scale rows 15 18 17
Lateral scale rows 67 75 76
Patch of ctenoid scales under pectoral fin absent absent absent
TORNABENE ET AL.
44 · Zootaxa 3447 © 2012 Magnolia Press
of preopercle; papillae row n continuous across dorsal midline; papillae row x
1
continuous from above pore F to
above base of pectoral fin.
FIGURE 1. Microgobius urraca holotype, AMNH 255033, 69.4 mm SL, female, at time of collection (A) and preserved (B).
Photographs by JVT. Editing by DRR.
Vertebral skeleton: precaudal vertebrae 11; caudal vertebrae (including terminal element) 16; dorsal fin
pterygiophore formula 3(221110); two anal fin pterygiophores preceding first haemal arch.
Pigmentation (based on freshly collected specimens unless otherwise noted): head brownish grey, with an
indistinct silvery blotch at the lower corner of the operculum; iris creamy yellow; body uniformly light brownish-
grey (pale grey to yellow in preservation); anterior half of trunk with four or five narrow, wavy, diffuse pale vertical
“Y” shaped bars; epaxial myosepta unpigmented; first dorsal fin with a light grey-brown base, pale grey outer half,
those two color areas separated by a conspicuous, horizontal oval blackish blotch across the center of the fifth to
seventh spines; second dorsal fin darker posteriorly than anteriorly, with a dark grey base, grey-brown distal half,
those two zones separated by a narrow blue-white stripe (stripe not apparent in preservation); anterior third of anal
fin dark grey basal on basal quarter and paler grey on distal three-quarters; the posterior two-thirds of the fin is
uniformly dark grey; caudal fin very dark, nearly black, with two blue-white stripes along its entire length above
midline and one blue-white stripe below midline; pelvic and pectoral fins uniformly light grey; abdominal region
pale; prepelvic region lightly pigmented with scattered melanophores; gular region pale.
Habitat. Microgobius urraca was collected in depths ranging from 12–20 m over sand or sand and leaf litter
bottoms. In collections where leaf litter was present this species was collected with several specimens of
Ptereleotris carinata and M. erectus. Microgobius urraca may be a burrowing species (see Discussion section
below).
Distribution. Known only from the Pacific coast of western Panama (Figure 3)
Etymology. The specific epithet urraca is in reference to the Smithsonian Tropical Research Institute’s
research vessel the Urraca, which served the institute between 1994–2007. Microgobius urraca was collected on
one of the many expeditions throughout the tropical eastern Pacific and Caribbean by the R/V Urraca, which
contributed a wealth of information on fish diversity in the tropical Americas. The species name is to be treated as
a noun in apposition. The common name “dark-finned sand goby is given in reference to the greyish-black second
dorsal, anal and caudal fins and the sandy habitat over which it occurs.
Zootaxa 3447 © 2012 Magnolia Press · 45
NEW MICROGOBIUS SPECIES FROM THE TROPICAL EASTERN PACIFIC
FIGURE 2. Sensory papillae and head pore pattern of M. urraca holotype AMNH 255033. Illustrations by JVT.
Comparisons. Microgobius urraca differs from all other eastern Pacific species of Microgobius except M.
erectus in having counts of I,14 in both the second dorsal and anal fins (all other species typically have
15 rays in
the second dorsal and anal fins). Microgobius urraca is most similar morphologically to M. erectus, but differs in
possessing a higher lateral scale count (67–76 vs
48 in M. erectus), scales entirely cycloid and not easily lost, a
dark blotch on the first dorsal fin (vs a pale/dusky fin with dark distal margin in female M. erectus), and in having
unpigmented epaxial myosepta (darkly pigmented in preserved specimens of M. erectus). The absence of ctenoid
scales under the pectoral fin further distinguishes M. urraca from M. erectus, M. cyclolepis, M. curtus, M. crocatus,
M. miraflorensis, and M. tabogensis. Like most species of Microgobius, M. urraca can also be distinguished from
its congeners by color patterns in life. No other species of Microgobius possesses a prominent sooty blotch on the
first dorsal fin, dark grey anal and second dorsal fins, and a blackish caudal fin with three blue-white stripes.
Microgobius urraca replaces M. brevispinis as the largest species in the genus (69.4 mm SL vs 64.6 mm SL,
maximum size of M. brevispinis, SIO62-719)
Discussion. Birdsong (1981) reported M. erectus from mud and broken shell bottoms from 15–30 m. Many M.
erectus were collected from the 2003 Urraca Panama expedition, several of which were collected with M. urraca
in a trawl over sand and leaf litter (field number JVT-03-210, AMNH 255301 and field number JVT-03-209,
AMHH 255297) and others were collected over sand and mud. Nearly all M. erectus specimens from these
collections had lost most of their scales and fins were severely damaged. The ease at which scales were lost and the
TORNABENE ET AL.
46 · Zootaxa 3447 © 2012 Magnolia Press
delicate fin membranes of M. erectus led Birdsong (1981) to conclude that M. erectus, unlike many other
Microgobius species, likely did not burrow. Although the specimens of M. erectus collected in 2003 were heavily
damaged, the specimens of M. urraca from the same trawls had not lost scales and fins were more or less intact.
Following Birdsong’s rationale, it is possible that the partially imbedded nature of the scales and the integrity of the
fins in M. urraca indicate a burrowing lifestyle. Burrowing behavior may also explain why, despite heavy sampling
effort, so few specimens of M. urraca were collected in trawls in comparison to M. erectus, which were common in
trawls in the same area.
FIGURE 3. Collection localities for M. urraca holotype and paratypes.
The phylogenetic relationship between M. urraca, the morphologically similar M. erectus, and other
Microgobius species remain unclear. Birdsong (1981) struggled greatly to generate even a broad phylogenetic
hypothesis for the genus, noting inconsistent patterns of shared characters across species, difficulty in determining
ancestral/derived character states, and complex and contradicting patterns of sexual dimorphism (i.e. female
conditions in one species are the male conditions in other species, while yet other species are sexually
monomorphic). The only phylogenetic hypothesis to date was a molecular phylogeny of the Gobiosomatini based
on mtDNA by Rüber et al. (2003) which contained 6 named (plus one unidentified) Microgobius species. Although
more than half of the known named species of Microgobius were missing from this study the relationships shown
were statistically robust and can provide a temporary framework for assessing the evolution and distribution of
some morphological characters. When several morphological characters (i.e. predominant scale type, presence/
absence of a patch of ctenoid scales under pectoral fin, second dorsal/anal fin counts, filamentous dorsal spines,
presence/absence of a dorsal crest, head pores) are mapped onto the phylogeny of Rüber et al. (2003), many
character states appear to have either arisen or been lost more than once, to which the overall confusion alluded to
by Birdsong (1981) may be attributed. A comprehensive phylogenetic analysis that includes all 15 currently
recognized species of Microgobius and incorporates morphological characters and additional molecular data
(including nuclear loci) would help clarify the interspecific relationships of this diverse group.
Zootaxa 3447 © 2012 Magnolia Press · 47
NEW MICROGOBIUS SPECIES FROM THE TROPICAL EASTERN PACIFIC
TABLE 2. Morphological comparison of species of Microgobius. All measurements are means and are expressed in % SL. Fin
ray counts are modes followed by ranges in parentheses.
erectus urraca cyclolepis
Ocean Pacific Pacific Pacific
Distribution Southern Baja California,
northern and eastern Gulf of
California to Panama
Pacific coast of Panama West coast of southern Baja
California, northeast Gulf of
California to Colombia
Habitat coastal areas with sand, mud
and broken shell bottom
sandy bottom generally with
leaf litter (two collected with
leaf litter one over sand)
sand, sand/mud or mud bottom
Depth 3–54 m 12–20 m 1–35 m
Elongate first dorsal fin
spines
spine 5 sometimes slightly
elongate in both sexes
not elongate in either sex spines 2–6 moderately elongate
in both sexes
Second dorsal (total
elements)
15(14–15) 15 16(15–17)
Anal 15(14–15) 15 16(16–17)
Pectoral 23(20–23) 21–22 23(22–24)
Fleshy dorsal crest males and females—low males and females—low males-very low; females -large
Preopercle pores 2 rarely 3 2 3
Oculoscapular pores B',D,F,G,H' B',D,F,G,H' B',D,F,G,H'
Separation of supraorbital
cephalic canals (see
Birdsong 1981: Fig. 1)
canals join near interorbital pore canals join between orbits canals join between orbits
Dominant scale type on
body
cycloid cycloid mostly cycloid
Ctenoid scale patch under
pectoral fin
present absent present
Lateral scale rows and
extent of scales
< 48 (easily lost), just short of
pectoral fin axis
67–76, pectoral fin axis 46–55, pectoral fin axis
Epaxial myosepta darkly pigmented no pigment no pigment
Gill rakers 3+13 5+16 5+16
Teeth outer row of dentary 6–8 6–7 6–8
Mouth angle 70 deg 45–50 deg 60 deg
Pectoral fin length 25.5 18.7 24.9
Head length—males 24.4 22.4 28.6
Head length—females 24.2 22.3 27.3
Interorbital width 2.6 3.4 2.6
Caudal fin length 45.0 38.0 32.9
TORNABENE ET AL.
48 · Zootaxa 3447 © 2012 Magnolia Press
continued.
curtus emblematicus brevispinnis
Ocean Pacific Pacific Pacific
Distribution El Salvador to northern Peru Southeast Gulf of
California to northern
Peru
West coast of southern Baja
California, northeast Gulf of
California to Panama
Habitat muddy mangrove areas beach areas with muddy
shell bottoms
beaches and tidepools with muddy
shell bottoms
Depth 0.2–16 m 0–17 m 0–6 m
Elongate first dorsal fin
spines
spines 2–5 elongate in both
sexes
males spines 4–7
elongate, to caudal fin;
females only slightly
elongate
males spines 2–5 elongate, to caudal
fin; females only slightly elongate
Second dorsal (total
elements)
16(15–17) 17(16–18) 18(16–19)
Anal 16(16–17) 17(16–18) 18(16–19)
Pectoral 21(20–22) 20(18–23) 21(19–22)
Fleshy dorsal crest males and females—absent to
poorly developed
males and females—low,
poorly developed
males and females—moderate
Preopercle pores 2 2 2
Oculoscapular pores B',D,F,G,H' B',D,F,G,H' B',D,F,G,H'
Separation of supraorbital
cephalic canals (see
Birdsong 1981: Fig. 1)
canals mostly separate canals join through most
of length
canals mostly separate
Dominant scale type on
body
mostly cycloid all cycloid all cycloid
Ctenoid scale patch under
pectoral fin
present absent absent
Lateral scale rows and
extent of scales
62–78, pectoral fin axis 50–75, end before
pectoral fin axis
63–81, end under third spine of D1
Epaxial myosepta no pigment no pigment no pigment
Gill rakers 5+16 4+16 4+16
Teeth outer row of
dentary
6–8 4–5 6–8
Mouth angle 45 deg 25 deg 45 deg
Pectoral fin length 20.3 19.2 21.6
Head length—males 27.8 27.8 25.5
Head length—females 27.9 27.8 25.8
Interorbital width 3.0 2.3 2.9
Caudal fin length 29.8 27.6 29.3
Zootaxa 3447 © 2012 Magnolia Press · 49
NEW MICROGOBIUS SPECIES FROM THE TROPICAL EASTERN PACIFIC
continued.
crocatus miraflorensis tabogensis
Ocean Pacific Pacific Pacific
Distribution El Salvador to Ecuador West coast southern Baja California
(Bahia Magdalene), central eastern
Gulf of California to northern Peru
West coast of Baja
California(n. Bahia
Magdalena), to Peru
(Puerto Pizarro)
Habitat mangrove slough with
muddy detritus bottom
estuarine species, mud to silty sand
bottom
mangrove ares with mud-
sand bottoms
Depth 0–6 m 0–4 m 0–4 m
Elongate first dorsal fin
spines
males spines 3–5 elongate
to caudal fin; females
elongate to end of D2;
males spines 2–6 extend to caudal
fin; females to third ray of D2
spines 2–5 moderately
elongate in both sexes
Second dorsal (total
elements)
17(17–18) 17(16–18) 17(16–18)
Anal 18(17–18) 17(16–18) 17(16–18)
Pectoral 22(21–24) 21–22(20–23) 22(19–23)
Fleshy dorsal crest males—absent;
females—low
males and females—absent males—absent;
females—well developed
Preopercle pores 2 2 2
Oculoscapular pores B',D,F,G,H' B',D,F,H' B',D,F,H', pore F frequently
absent
Separation of supraorbital
cephalic canals (see
Birdsong 1981: Fig. 1)
canals widely divergent canals join between orbits canals join between orbits
Dominant scale type on
body
mostly cycloid mostly ctenoid mixed
Ctenoid scale patch under
pectoral fin
present, but small and
weakly ctenoid
present present
Lateral scale rows and
extent of scales
46–56, pectoral fin axis 40–48, end under posterior 1/3 of
pectoral fin
41–55, pectoral fin axis
Epaxial myosepta no pigment no pigment no pigment
Gill rakers 5+18 4+15 4+13
Teeth outer row of dentary 5–6 20 7–9
Mouth angle 50 deg 35 deg 40 deg
Pectoral fin length 24.9 25.7 24.0
Head length—males 27.1 28.8 27.3
Head length—females 24.8 27.5 25.8
Interorbital width 3.7 2.4 2.0
Caudal fin length 35.3 36.9 37.4
TORNABENE ET AL.
50 · Zootaxa 3447 © 2012 Magnolia Press
continued.
signatus microlepis meeki
Ocean Atlantic Atlantic Atlantic
Distribution Atlantic—Greater & Lesser
Antilles, coast of Venezuela
Southeast Florida (Jupitor Inlet
south through Flodida Bay) Dry
Tortugas, Bahamas, Yucatan,
Belize
Puerto Rico, Venezuela
south to Santos, Brazil
Habitat sandy bottom near islands calcareous bottoms shallow mud-bottom
mangrove areas
Depth 1–14 m 1.5–5.0 m 0–27 m
Elongate first dorsal fin
spines
males not elongate; females
spine 1 elongate to first ray of
D2
both sexes spines 2–6 slightly
delongate to fourth ray of D2
males spines 2–6 extend to
caudal fin and often
beyond; females only
slightly produced
Second dorsal (total
elements)
20(19–21) 18–19(16–20) 17(16–18)
Anal 21(20–22) 19(18–20) 17(16–18)
Pectoral 20–21(19–22) 21–22(20–23) 21–22(19–23)
Fleshy dorsal crest males and females—well
developed
males—low, slightly developed;
females—moderately developed
males—low; females—well
developed
Preopercle pores 3 3, middle pore very small 2
Oculoscapular pores B',D,F,G,H' B',D,F,G,H' B',D,F,G,H', pore G
frequently absent
Separation of
supraorbital cephalic
canals (see Birdsong
1981: Fig. 1)
canals mostly separate canals mostly separate canals joined between
orbits
Dominant scale type on
body
mostly cycloid mostly weakly ctenoid mostly ctenoid
Ctenoid scale patch under
pectoral fin
present, strongly ctenoid body mostly ctenoid body mostly ctenoid
Lateral scale rows and
extent of scales
77–90, pectoral fin axis 68–78, pectoral fin axis 46–60, pectoral fin axis
Epaxial myosepta no pigment no pigment no pigment
Gill rakers 5+16 4+12 4+13
Teeth outer row of
dentary
4–5 5–6 7–8
Mouth angle 45 deg 50 deg 40 deg
Pectoral fin length 20.1 24.9 males, 21.4 females 26.1
Head length—males 25.9 27.1 28.0
Head length—females 26.9 28.2 27.5
Interorbital width 3.3 3.2 2.1
Caudal fin length 33.4 35.0 41.0
Zootaxa 3447 © 2012 Magnolia Press · 51
NEW MICROGOBIUS SPECIES FROM THE TROPICAL EASTERN PACIFIC
continued.
thalassinus carri gulosus
Ocean Atlantic Atlantic Atlantic
Distribution Chesapeake Bay to Florida
(Cape Canaveral), northern
Gulf of Mexico to Texas
(Galveston)
Florida, northeast Gulf of
Mexico, Lesser Antilles to
Tobago
Chesapeake Bay to Florida;
Gulf of Mexico to Corpus
Christi, TX
Habitat muddy sand or mud bottoms coarse sandy bottom muddy-bottom, quiet waters
Depth 0–6 m 6–21 m 0–75 m
Elongate first dorsal fin spines males slightly elongate;
females not elongate
males spines 2–5 elongate,
spine 5 longest to two-
thirds length D2; females
not elongate
males spines 2–6 elongate,
raching midpoint of D2;
females not elongate
Second dorsal (total elements) 16(15–17) 16–17(15–18) 16–17(15–18)
Anal 17(15–17) 16–17(16–19) 16–17(16–18)
Pectoral 21–22(19–23) 21(20–24) 21–22(19–24)
Fleshy dorsal crest males—absent; females low
crest
males and females—absent males and females—absent
Preopercle pores 2 2 2
Oculoscapular pores B',D,F,H', pore D large B',D,F,G,H' B',D,F,G,H', pore D small,
pores F,G,H variably present
or absent
Separation of supraorbital
cephalic canals (see Birdsong
1981: Fig. 1)
canals joined between orbits canals mostly separate canals join near posterior
half of orbits
Dominant scale type on body mostly cycloid mostly ctenoid mostly cycloid
Ctenoid scale patch under
pectoral fin
present body mostly ctenoid present
Lateral scale rows and extent of
scales
43–50, pectoral fin axis 50–62, pectoral fin axis 44–54, pectoral fin axis
Epaxial myosepta no pigment no pigment no pigment
Gill rakers 5+16 5+15 3+10
Teeth outer row of dentary 7–9 4–5 7–9
Mouth angle 45 deg 30 deg 30 deg
Pectoral fin length 26.5 18.3 24.5
Head length – males 26.9 27.7 30.6
Head length – females 26.5 27.7 28.9
Interorbital width 2.5 4.1 2.4
Caudal fin length 34.0 29.7 31.7
TORNABENE ET AL.
52 · Zootaxa 3447 © 2012 Magnolia Press
Key to the Pacific species of Microgobius
The following key to the Pacific species of Microgobius is largely based on diagnostic characters described by
Birdsong (1981). Additional diagnostic pigmentation characters have been included in the key and photographs of
freshly collected specimens of all Pacific Microgobius are included here to assist with identification of fresh
material (Figures 4–6). A more comprehensive comparison of morphological features across the entire genus,
summarizing data from Birdsong (1981) and data from additional material examined here (Appendix I), is given in
Table 2.
FIGURE 4. Photographs of freshly collected M. brevispinis, M. curtus, and M. crocatus. Photos by JVT, editing by DRR.
FIGURE 5. Photographs of freshly collected M. erectus, M. emblematicus, and M. miraflorensis. Photos by JVT and Gerry
Allen, editing by DRR.
Zootaxa 3447 © 2012 Magnolia Press · 53
NEW MICROGOBIUS SPECIES FROM THE TROPICAL EASTERN PACIFIC
FIGURE 6. Photographs of freshly collected M. cyclolepis and M. tabogensis. Photographs of males not available. Photos by
Gerry Allen and JVT, editing by DRR.
1a. Second dorsal fin elements I,15 or fewer (rarely I,16); anal fin elements I,15 or fewer (rarely I,16); scales mostly cycloid . . .2
1b. Second dorsal fin elements I,16 or more (rarely I,15); anal fin elements I,16 or more (rarely I,15); scales cycloid or ctenoid .5
2a. Second dorsal fin elements I,14 or fewer; anal fin elements I,14 or fewer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
2b. Second dorsal fin elements I,15 (rarely I,14 or I,16); anal fin elements I,15 (rarely I,16). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
3a. No patch of ctenoid scales under pectoral fin base; all scales on body cycloid, lateral scales 67–76; epaxial myosepta not darkly
pigmented; caudal fin blackish, with three blue-white stripes, an oval blackish blotch on rear of first dorsal fin. . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M. urraca
3b. Patch of ctenoid scales under pectoral fin base; patch of 10–22 weakly ctenoid scales sometimes present immediately below
first and second dorsal fin, remaining scales cycloid, lateral scales less than 48; epaxial myosepta darkly pigmented in pre-
served specimens; body in life silvery brown in both sexes (pale in preservation), fins grey or silvery . . . . . . . . . . . M. erectus
4a. Preopercular sensory canal with three pores; lateral scale rows less than 60; pectoral rays 22–24; a prominent crescentic to
ovoid dark blotch on shoulder below anterior of dorsal fin; anterior half of second dorsal fin of females often with a blue-white
diagonal streak; no distinct rows of spots on first dorsal fin; no pale or blue vertical bars on body of females . . . M. cyclolepis
4b. Preopercular sensory canal with two pores; lateral scale rows more than 60; pectoral rays 20–21; dark spot on body below
anterior dorsal spines indistinct; both sexes with two to four rows of prominent orange spots along both dorsal fins, spots dark
in preservation; female often with pale or blue vertical bars both before and after pectoral fin base in life (bars less apparent in
preservation); male with front half of body and head behind eye densely spotted with orange (not apparent in preservation). . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. curtus
5a. Scales entirely cycloid, no ctenoid patch beneath pectoral fin; pectoral fin short, usually 18–24% of SL; both sexes with low,
fleshy dorsal crest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
5b. Patch of ctenoid scales present beneath pectoral fin; remaining scales cycloid or ctenoid; pectoral fin long, usually 23–27% of
SL; fleshy dorsal crest absent in males, present or absent in females. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
6a. Dorsum with a row of four or five dashes (short, thin dark lines) along the dorsal fin base (sometimes with four or five dark
saddles below them), sometimes a diffuse dark blotch on shoulder below front dorsal spines; caudal fin of both sexes with an
oblique red stripe across lower half (not apparent in preservation); about four enlarged, caninoid teeth in outer row of each den-
tary; second dorsal fin elements usually I,16; anal fin elements usually I,16 . . . . . . . . . . . . . . . . . . . . . . . . . . M. emblematicus
6b. Dorsum without dark dashes or saddles; males with a dark bar on shoulder bordered posteriorly with blue or yellow in life, and
often with a short iridescent blue stripe below posterior half of second dorsal and two large round yellow spots above anal fin ;
an iridescent yellow bar with a blue anterior border on shoulder in living females; about six or seven enlarged, caninoid teeth in
outer row of each dentary; second dorsal fin elements usually I,17; anal fin elements usually I,17 . . . . . . . . . . . M. brevispinis
TORNABENE ET AL.
54 · Zootaxa 3447 © 2012 Magnolia Press
7a. A dark spot (sometimes diffuse) or bar present on body below origin of first dorsal fin; second dorsal fin elements usually I,16;
anal fin elements usually I,16; no elongate iridescent blue blotch on body above and before anus. . . . . . . . . . . . . . . . . . . . . . .8
7b. No dark spot or bar on body below origin of first dorsal fin; second dorsal fin elements I,16–17; anal fin elements usually I,17;
in life, both sexes with an elongate iridescent blue blotch on upper belly above and before anus, and the ventral edge of the
caudal fin yellow (lost in preservation); male with anal and pelvic fins bordered in yellow in life, female with a yellow stripe
along base of anal fin in life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. crocatus
8a. Each dentary with about 15–20 teeth in outer row; fleshy dorsal crest absent in both sexes; often with a dark vertical bar on
shoulder, and sometimes one to five faint vertical bars on trunk behind shoulder bar in preservation (due to the poor quality of
our photos, life color patterns cannot be accurately defined) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M. miraflorensis
8b. Each dentary with about seven to nine teeth in outer row; fleshy dorsal crest well developed in females; both sexes with a dif-
fuse dark spot on body below origin of first dorsal fin; in life, both sexes with a series of four or five large iridescent blue spots
along mid flank, another series of two or three iridescent blue spots along side of belly beneath pectoral fin (spots lost in pres-
ervation) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M. tabogensis
Acknowledgements
We thank J. Earle and the crew of the R/V Urraca for their assistance in the field. Funding for field work was
provided by Smithsonian Tropical Research Institute to DRR. R. Arrindell, B. Brown and R. Schelly at AMNH;
and J. Williams, C. Baldwin and D. Pitassy at USNM provided assistance with digital radiographs and museum
material. Special thanks to S. Large for his assistance with the map and F. Pezold for his review of an earlier
version of this paper.
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APPENDIX I. Additional Microgobius material examined.
Microgobius curtus: AMNH 255302, field number JVT-03-202, 1 specimen, Panama, Isla Brava north side, rotenone
collection, 8.2609, -82.3267, mangrove area with fine mud, J.L. Van Tassell and D.R. Robertson, R/V Urraca, 15 June
2003.
Microgobius emblematicus: AMNH 255300, field number JVT-01-103, 15 specimens, Panama, Ancon Boat Club, south of boat
ramp in mangrove creek, rotenone collection, 8.9392, -079.5547, mud and root substrate, J.L. Van Tassell and D.R.
Robertson, 8 April 2001. AMNH 255303, field number JVT-EL-01-009, 3 specimens, El Salvador, Gulf de Fonseca, Isla
Meanguera, rotenone collection, 13.1600, -87.7085, large gorgonian covered boulders with barnacle rubble substrate, J.L.
Van Tassell and D.R. Robertson, R/V Urraca, 8 March 2001.
Microgobius erectus: AMNH 255296, 1 specimen, Gulf of Chiriqui, trawl 56, 7.9295, -81.6645 to 7.9091, -81.6528, 30.7-32.7
m, 27 April 2000, D.R. Robertson and J.L. Van Tassell, R/V Urraca. AMNH 255297, field number JVT-03-209, 55
specimens (4 examined), Gulf of Chiriqui, North of Isla Secas near main land, trawl 68, 8.12583, -81.8555 to 8.11483, -
81.83083, 18.4-19.7 m, sand with leaf litter substrate, 16 June 2003, D.R.Robertson and J.L. Van Tassell, R/V Urraca.
AMNH 255298, field number JVT-EL-01-082, 9 specimens, El Salvador, Pacific, trawl, 21 March 2001, D.R. Robertson
and J.L. Van Tassell, R/V Urraca. AMNH 255301, field number JVT-03-210, 60 specimens, Gulf of Chiriqui, North of
Isla Secas near main land, trawl 69, 08.1135, -081.8336 to 08.1128, -081.8573, 20.5-21.9 m, sand with leaf litter substrate,
16 June 2003, D.R. Robertson and J.L. Van Tassell, R/V Urraca. AMNH 255304, field number JVT-EL-01-058, 1
specimen, El Salvador, off Tamarindo, trawl, 13.202, -87.8798 to 13.172, -87.8756, 6.0-8.0 m, mud and tree litter, 18
March 2001, D.R. Robertson and J.L. Van Tassell, R/V Urraca.
Microgobius gulosus: AMNH 255305, field number JVT-07-789, 15 specimens, Texas, near town of Fulton, Copano Bay, Salt
Lake, rotenone collection, 28.0777, -97.0860, 0-1 m, sand substrate with grass along edge of water, J.L. Van Tassell, D.R.
Robertson, L. Tornabene, 16 October 2007.
Microgobius tabogensis: AMNH 255299, field number JVT-EL-01-014, 4 specimens, El Salvador, Golfo de Fonseca, Estero El
Tamarindo, 13.2036, -87.9112, 0-1 m, rotenone collection, intertidal area silty sand, scattered rocks and logs, 10 March
2001, J.L. Van Tassell and D.R. Robertson, R/V Urraca. AMNH 255306, 4 specimens, Gulf of Chiriqui, Trawl 52, D.R.
Robertson and J.L. Van Tassell, R/V Urraca, 26 April 2000. AMNH 255307, field number JVT-03-202, 1 specimen, Gulf
of Chiriqui, Isla Brava north side, 8.2609, -82.3267, 0-1 m, rotenone collection, intertidal mangrove area with fine mud, 15
June 2003, D.R. Robertson and J.L. Van Tassell, R/V Urraca.
