Content uploaded by James Lamsdell
Author content
All content in this area was uploaded by James Lamsdell on Mar 26, 2014
Content may be subject to copyright.
Early Devonian stylonurine eurypterids from
Arctic Canada
James C. Lamsdell, Simon J. Braddy, Elizabeth J. Loeffler, and David L. Dineley
Abstract: Two new stylonurine eurypterids are described from the Peel Sound Formation (Early Devonian, Lochkovian)
of the northern coast of Prince of Wales Island, Nunavut, Arctic Canada. Associations including pteraspids and ostracodes
indicate a fluvial depositional environment. An almost complete stylonurid, Pagea plotnicki sp. nov., is recognized by its
large size and lack of vaulting on the carapace, and it provides evidence that Stylonurus and Pagea are sister-taxa. Also, a
smaller incomplete rhenopterid assigned to Leiopterella tetliei gen. et sp. nov., is characterized by its broad turbinate cara-
pace and lack of cuticular sculpture. This assemblage provides the first Canadian record of Pagea, and the youngest occur-
rence of a rhenopterid outside the Rheno-Hercynian Terrane, indicating that these taxa were more geographically
widespread than previously supposed.
Re
´sume
´:Deux nouveaux eurypte
´rides stylonuride
´s provenant de la Formation de Peel Sound (De
´vonien pre
´coce, Lochko-
vien) de la co
ˆte nord de l’ı
ˆle Prince-de-Galles, au Nunavut, dans l’Arctique canadien, sont de
´crits. Des associations com-
prenant des pte
´raspides et des ostracodes indiquent un milieu de de
´po
ˆt fluvial. Un stylonuride quasi complet, Pagea
plotnicki sp. nov., se distinguant par sa grande taille et l’absence de structures en vou
ˆte sur sa carapace, appuie l’hypo-
the
`se selon laquelle Stylonurus et Pagea seraient des taxons fre
`res. En outre, un rhe
´nopte
´ride incomplet plus petit affecte
´a
`
Leiopterella tetliei gen. et sp. nov. se distingue par sa large carapace turbine
´e et l’absence de sculpture cuticulaire. Cet as-
semblage constitue le premier exemple canadien documente
´de Pagea et l’exemple le plus re
´cent d’un rhe
´nopte
´ride a
`l’ex-
te
´rieur du terrane rhe
´no-hercynien, ce qui e
´largie la distribution ge
´ographique de ces taxons.
Introduction
Eurypterids (Chelicerata) are Palaeozoic aquatic predatory
arthropods. Some grew to gigantic proportions, probably
driven by environmental stress and competition with other
animals (Lamsdell and Braddy 2010). Eurypterids are glob-
ally widespread but tend to be restricted to Konservat–La-
gersta
¨tte because of their unmineralized cuticle (Gupta et al.
2007), the most famous of which are found along the eastern
seaboard of the USA (Clarke and Ruedemann 1912). Most
eurypterids reported from Canadian localities represent nek-
tonic forms with prosomal appendage VI modified into a
swimming paddle (Eurypterina). These are known primarily
from the Late Ordovician (Stott et al. 2005) and Silurian
(Copeland and Bolton 1960, 1985; Rudkin et al. 1998) of
Ontario, with more recent reports from the Late Ordovician
of Manitoba (Young et al. 2007). The Canadian Arctic re-
cord of Eurypterina is very sparse; only Eurypterus,Carci-
nosoma,Rhinocarcinosoma, and Erieopterus have so far
been reported, from the Silurian and Early Devonian
(Braddy and Dunlop 2000, and references therein), based on
fragmentary specimens of isolated carapaces or appendages.
Enigmatic raptorial appendages assigned to Angustidon-
tus, known from the Late Devonian of Yukon Territory and
the lowermost Carboniferous of Alberta (Copeland and Bol-
ton 1960), were previously suggested to have affinities with
Eurypterida (Briggs 1979; Braddy and Dunlop 2000),
although more recent work has convincingly shown that An-
gustidontus is a eumalacostracan crustacean (Rolfe and Dzik
2006).
Eurypterid trackways are also known from the Silurian of
Ontario (Braddy and Dunlop 2000), the Early Devonian of
New Brunswick (Greiner 1972), and the Middle Devonian
of Quebec (Braddy and Milner 1998), some of which are at-
tributed to large stylonurine eurypterids.
The fossil record of Canadian Stylonurina (eurypterids
with their posterior prosomal appendages adapted for walk-
ing) is even sparser than that of the Eurypterina. Only four
stylonurine species are known: (1) a kokomopterid (Rudkin
et al. 1998); (2) an unidentified taxon from the Middle Dev-
onian of Quebec (Jeram 1996); (3) a specimen described as
Stylonurus sp. from the Early Devonian of Cornwallis Island
(Plotnick and Elliott 1995); and, (4) Drepanopterus sp. from
the Early Devonian of Anderson River in the Northwest Ter-
ritories (Braddy and Dunlop 2000; Lamsdell et al. 2009).
In this paper, we report on a new Early Devonian euryp-
terid fauna from the Peel Sound Formation, 29 km south-
west of Bellot Cliff on the north coast of Prince of Wales
Island, Nunavut, in the Canadian Arctic (Dineley 1994,
Fig. 1, locality F). The strata at this locality have been dated
as Early Devonian (Lochkovian), based on agnathan and
gnathostome vertebrate occurrences (Elliott 1984).
The palaeoenvironment most likely represents an alluvial
fan system (Broad et al. 1968), with the marine Douro For-
mation grading into the nonmarine Peel Sound Formation
Received 11 February 2010. Accepted 25 May 2010. Published
on the NRC Research Press Web site at cjes.nrc.ca on
27 October 2010.
Paper handled by Associate Editor J. Jin.
J.C. Lamsdell,1,2 S.J. Braddy, E.J. Loeffler, and D.L. Dineley.
Department of Earth Sciences, University of Bristol, Wills
Memorial Building, Queen’s Road, Bristol, BS8 1RJ, UK.
1Corresponding author (e-mail: lamsdell@ku.edu).
2Present address: Paleontological Institute, University of Kansas,
1475 Jayhawk Boulevard, Lawrence, KS 66045, USA.
1405
Can. J. Earth Sci. 47: 1405–1415 (2010) doi:10.1139/E10-053 Published by NRC Research Press
(Dineley 1965). The fossils are found in two lenses of calca-
reous siltstone and sandstone, which yield enormous quanti-
ties of well preserved, transported material. One lens is
characterized by numerous well-preserved cephalaspids,
with associated Ctenaspis, and a few pteraspids (Dineley
1966). The other contains abundant large pteraspids, Ctenas-
pis, arthrodires (Arctolepida), acanthodian spines, possible
antiarchs, arthropods, and vascular plant material. These ar-
thropods consist of the stylonurines reported here, fragments
of pterygotid cuticle, an arachnid, and ostracodes.
Materials and methods
The material described here was collected in 1973 as part
of a joint University of Bristol (Bristol, UK) and University
of Ottawa (Ottawa, Ontario, Canada) expedition led by DLD
and Brian Jones. The eurypterids are preserved in a dark
grey, poorly laminated pale brown marl matrix. Cuticle is
often preserved as a darker brown film. The fossils were
photographed using a Nikon D40 with 60 mm micro Nikkor
lens, under water to emphasise contrast, and drawn using
Adobe Illustrator CS3. All measurements are given in milli-
metres. Morphological terminology follows Tollerton (1989)
and Selden (1981), while higher systematics follows Lams-
dell et al. (2010). The phylogenetic analysis was performed
using Phylogenetic Analysis Using Parsimony (PAUP)*
4.0b10 (Swofford 2003), using the matrix in Lamsdell et al.
(2010) with the addition of the taxa described herein and
Pagea symondsii along with several characters that help to
differentiate these taxa. The synziphosurine Weinbergina
opitzi was retained as outgroup for the reasons outlined by
Lamsdell et al. (2010), while Eurypterina is represented by
Moselopterus ancylotelson,‘‘Drepanopterus’’ bembycoides,
Vinetopterus struvei,Onychopterella augusti,Eurypterus re-
mipes, and Hughmilleria socialis. Multiple exemplars of the
suborder are included as they more accurately represent the
character states and transitions of the group than a single
exemplar, such as Eurypterus or a composite taxon would
(see Brusatte 2010). The material described herein is depos-
ited in the collections of the Canadian Museum of Nature
(CMN 53570 – CMN 53573), Ottawa, Canada.
Systematic palaeontology
Order Eurypterida Burmeister, 1843
Suborder Stylonurina Diener, 1924
Superfamily Stylonuroidea Diener, 1924
Family Stylonuridae Diener, 1924
= Laurieipteridae Kjellesvig-Waering, 1966
Diagnosis
Stylonuroidea with undifferentiated opisthosoma, proso-
mal appendages II–IV spiniferous Ctenopterus-type and V–
VI non-spiniferous Pagea-type.
Remarks
Kjellesvig-Waering (1966) separated the Laurieipteridae
from the Stylonuridae based on the broad, rectangular shape
of their metastoma. The prosomal appendages of Pagea in-
dicate that it belongs within the Laurieipteridae, and several
features in Stylonurus, including its long telson and centrally
positioned lateral eyes, also indicate affinities with the Laur-
ieipteridae. The two families were, therefore, synonymized
by Lamsdell et al. (2010).
Genus Pagea Waterston, 1962
Pagea plotnicki sp. nov
(Figs. 1a,1b;2a,2b)
1995 Stylonurus sp. Plotnick and Elliott, p. 399, fig. 2.
Etymology
Named after Professor Roy Plotnick, who described a
specimen now assigned to this new species with Professor
David Elliott in 1995.
Diagnosis
Large Pagea lacking clear vaulting of the carapace or tri-
lobation of the opisthosoma; spines on appendage IV broad
and robust; tergites with acicular scales along their posterior
margins.
Type material
CMN 53570 (holotype), single large specimen comprising
carapace, opisthosomal segments 1–12 and prosomal appen-
dages III, IV, V, and VI; CMN 53571 (paratype) prosomal
appendage; CMN 53572 (paratype) base of the pretelson.
Additional material
UA10477 (University of Alberta, Edmonton, Canada),
large specimen consisting of carapace and anterior tergites
(Plotnick and Elliott 1995).
Horizon and locality
As described earlier in the text.
Description
Holotype CMN 53570 (Fig. 1a,1b). Almost complete
specimen lacking telson and majority of anterior prosomal
appendages. Opisthosomal segments dimensions shown in
Table 1. Carapace has a preserved length of 160 mm and a
width of 120 mm. Marginal rim 7 mm wide along the ante-
rior edge, narrowing evenly posteriorly to 2 mm. Lateral
eyes positioned centrimesially, 50 mm apart with an oval
ocular area 30 mm long and 27 mm wide. Median ridge sit-
uated between the lateral eyes, 14 mm wide and 91 mm
long, terminating at the probable location of the ocelli and
extending back to the raised posterior of the carapace.
Raised area correlates with the position of the coxae of ap-
pendage VI, which were very large. Carapace notches in-
wards along the lateral edge, 67 mm from base.
Ornamentation appears dimpled with occasional semi-lunate
scales. Two prosomal appendages are articulated on the
right side of the carapace; appendage V has three podomeres
preserved in full (V-3, V-4, V-5), and appendage VI only
two (VI-4, VI-5). Single podomere joint of appendage IV
also preserved, 12 mm wide. V-3 is 18 mm long, 20 mm
wide, V-4 is 59 mm long, 24 mm wide at base narrowing
to 16 mm distally. V-5 preserved length 64 mm, 12 mm
wide at base narrowing to 7 mm distally. VI-4 is 45 mm
long, 11 mm wide. VI-5 preserved length 50 mm, narrows
distally with grooves along each lateral edge. Left side of
1406 Can. J. Earth Sci. Vol. 47, 2010
Published by NRC Research Press
carapace preserves four appendages; single podomere of ap-
pendage III, 50 mm long and 15 mm wide, with four pairs
of fixed spines, 5 mm wide and 10 mm long, single poorly
preserved podomere of appendage IV, 44 mm long and
11 mm wide, six podomeres of appendage V and a distal po-
domere of appendage VI. V-2 and V-3 are poorly preserved,
V-4 is 35 mm long and 14 mm wide, V-5 is 76 mm long,
10 mm wide at its base expanding distally to 11 mm, bow-
ing centrally to 9 mm with grooves 2 mm from each lateral
edge. V-6 is 36 mm long and 11 mm wide, V-7 is indistinct,
34 mm long and 11 mm wide. The opisthosoma is raised
centrally with faint axial furrows running along either side.
Each mesosomal segment has a transverse ridge 7 mm from
its anterior margin. Pretelson greatly elongated, bears a me-
dian keel 23 mm wide, 29 mm from the lateral pretelson
edge. The mesosomal segments have rounded edges, while
the metasomal segments bear small epimerae.
Paratype CMN 53571 (Fig. 2a). Prosomal appendage con-
sisting of two podomeres of Pagea-type. First podomere
85 mm long, 10 mm wide expanding to 15 mm distally,
grooved along each lateral edge. Second podomere has a
preserved length of 59 mm with a median ridge running
along its length.
Paratype CMN 53572 (Fig. 2b). Segments 10 and 11 of
metasoma and pretelson. Segment 10 is 72 mm wide, length
unknown. Segment 11 preserved width 60 mm, length
32 mm. Pretelson has a preserved length of 130 mm and is
keeled medially.
Remarks
Although lacking some of the diagnostic ventral struc-
tures, these specimens display several characteristics that
firmly place them in the genus Pagea:(i) the multiple pairs
of fixed spines on appendage III; (ii) the quadrate-shaped
carapace; (iii) the broad marginal rim of the carapace nar-
rowing posteriorly; (iv) the oval shape, large size, and cen-
trimesial position of the lateral eyes; (v) the Pagea-type
posterior pairs of prosomal appendages; (vi) the axial fur-
rows on the opisthosoma; and (vii), the broad, elongated pre-
telson with its median keel.
Fig. 1. Pagea plotnicki sp. nov., Prince of Wales Island, Nunavut, Canada. (a) Holotype CMN 53570. Scale bar = 4 cm. (b) Interpretive
drawing of CMN 53570. Scale bar = 4 cm. MR, marginal rim; C, carapace; LE, lateral eyes; MRi, median ridge; S, spines; AF, axial fur-
rows; TR, transverse ridges. Prosomal appendages are labelled with Roman numerals and individual podomeres with Arabic numerals from
proximally to distally.
Lamsdell et al. 1407
Published by NRC Research Press
Only two other species of Pagea are known, P. sturrocki
and P. symondsii, both from the Early Devonian (Lochko-
vian) of the UK. The type species, P. sturrocki Waterston,
1962, is known only from the holotype. The general mor-
phology of P. plotnicki n. sp. corresponds well to P. stur-
rocki, although the axial furrows are not so well developed
and the opisthosoma of the holotype is much broader, a gen-
eral trait of juvenile eurypterids (Andrews et al. 1974). The
adult P. sturrocki has a length of 65 cm, while CMN 53570
has an observed length of 54 cm, with an estimated total
length of 75 cm; P. plotnicki reached a far greater adult size.
Plotnick and Elliott (1995) described a stylonurine euryp-
terid from Arctic Canada as Stylonurus sp. (UA10477),
based on similarities in the form of the carapace median
ridge, lateral eye shape, and shortening of the first tergite.
However, it differs significantly from the type species, Sty-
lonurus powriensis, in lacking trilobation of the opistho-
soma. The holotype specimen of P. plotnicki corresponds
well with UA10477, showing identical form and positioning
of the lateral eyes and shape of the carapace, and they are
herein considered conspecific. The opisthosoma of
UA10477 is much narrower, in keeping with that of Pagea
sturrocki, and the specimen has an estimated total length of
115 cm, suggesting that it is the adult form of CMN 53570.
Superfamily Rhenopteroidea Størmer, 1951 (nom. trans.
Lamsdell et al. 2010)
Family Rhenopteridae Størmer, 1951
= Brachyopterellidae Tollerton, 1989
= Alkenopteridae Poschmann and Tetlie, 2004
Diagnosis
Rhenopteroidea with single fixed spines on prosomal ap-
pendage III and a short telson. Appendages II–IV with short,
fixed spines; V–VI non-spiniferous.
Remarks
The Rhenopteridae, as currently defined, contains five
genera, most of which had previously been placed in mono-
typic families, forming a basal clade of relatively primitive
stylonurines (Lamsdell et al. 2010).
Genus Leiopterella gen. nov
Etymology
Leio is from the Greek leios, meaning smooth. pterella is
from the Greek pteros for wing, the traditional suffix ap-
plied to eurypterid genera.
Diagnosis
Rhenopteridae with turbinate carapace lacking cuticular
sculpture; ventral sutures of Eurypterus-type; gnathobases
large and robust; type-B genital appendage short with bi-
lobed termination.
Leiopterella tetliei sp. nov
(Figs. 3a,3b)
Etymology
Named after Dr. O. Erik Tetlie for his many contributions
to the study of eurypterids.
Type material
Holotype CMN 53573, single small specimen consisting
of prosoma and four opisthosomal segments, detailing coxae,
faintly preserved metastoma, ventral sutures, portions of pro-
somal appendages IV–VI and type B genital appendage.
Horizon and locality
As described earlier in the text.
Description
Holotype CMN 53573 (Fig. 3a,3b) carapace turbinate,
37 mm long and 29 mm wide at its base, lateral angle 758.
Narrow marginal doublure 1 mm wide. Ventral sutures
faintly preserved, of Eurypterus-type, with right median
ventral plate absent. Left chelicera faintly preserved, length
3 mm, width 2 mm. Left coxae well preserved; II-1 length
5 mm, width 3 mm; III-1 length 7 mm, width 3 mm; IV-1
length 7 mm, width 3 mm, with attached IV-2 (3 mm long,
3 mm wide); V-1 length 7 mm, width 3 mm. VI-1 length
23 mm, width 15 mm. Large, robust gnathobases preserved
as dark stains on right side. Two disarticulated prosomal ap-
Fig. 2. Pagea plotnicki, Prince of Wales Island, Nunavut, Canada.
(a) Paratype CMN 53571. Prosomal appendage. Scale bar = 5 cm.
(b) Paratype CMN 53572. Opisthosomal segments 10 and 11 and
pretelson. Scale bar = 5 cm.
1408 Can. J. Earth Sci. Vol. 47, 2010
Published by NRC Research Press
pendages preserved to the right of the specimen; first (prob-
ably IV) three podomeres 11 mm, 12 mm, and 10 mm long,
each 3 mm wide with small, fixed spines at their distal mar-
gins, second (probably V) two podomeres 10 mm long
3 mm wide and 4 mm long, 3 mm wide. Metastoma faintly
preserved between coxae VI; anterior and posterior margins
visible, while sides are barely distinguishable. Shape oval
with anterior notch; width 15 mm, length 18 mm. Append-
age VI partially preserved on right side. VI-1 length
23 mm, width 15 mm; VI-2 length 4 mm, width 6 mm; VI-
3 length 8 mm, width 6 mm, VI-4 length 11 mm, width
4 mm, VI-5 length 6 mm, width 4 mm, VI-6 length 6 mm,
width 4 mm. Genital operculum 10 mm long and 32 mm
wide, preserving anterior, median and posterior plates. Type
B genital appendage length 8 mm, width 3 mm, with bi-
lobed termination. Three blattfu
¨sse preserved: first 9 mm
long and 32 mm wide; second 10 mm long, 32 mm wide;
third 9 mm long, preserved width 16 mm. No ornamentation
or cuticular sculpture is evident on the specimen.
Remarks
The specimen probably represents an exuvium, an inter-
pretation suggested by the absence of one of the ventral
plates, which detach during ecdysis (Tetlie et al. 2008).
Although it as been suggested that eurypterids moulted in a
supine position (Tollerton 1997) Tetlie et al. found no evi-
dence for a preferred dorsal or ventral posture in eurypter-
ids, while moults could be reoriented after ecdysis by water
currents (Braddy 2001).
Leiopterella gen. nov. shows several similarities with the ge-
nus Brachyopterella,fromtheWenlockofScotlandandNor-
way, particularly the anterior widening of the carapace.
Brachyopterella was transferred to the Rhenopteridae by Lams-
dell et al. (2010) despite its possession of an epistoma, a charac-
ter usually associated with the Laurieipterinae in stylonurines.
The underside of Leiopterella bears a resemblance to Rhe-
nopterus, as reconstructed by Størmer (1936), yet differs in
the shape of the carapace and the lack of cuticular ornamen-
tation. The genital appendage faintly preserves a bilobed ter-
Table 1. Proportions of the holotype specimen CMN 53570 of Pagea plotnicki.
Proportions (length/width) of opisthosomal segments, in specimen CMN 53570
1 2 3 4 5 6 7 8 9 10 11 12
13/132 21/134 37/149 35/153 33/142 39/142 23/129 24/132 19/122 22/119 25/100* 84*/89*
*Preserved dimensions.
Fig. 3. Leiopterella tetliei gen. et sp. nov., Prince of Wales Island, Nunavut, Canada. (a) Holotype CMN 53573. Scale bar = 1 cm. (B)
Interpretive drawing of CMN 53573. Scale bar = 1 cm. Abbreviations as in Fig. 1bwith the addition of TS, transverse suture; MVP, median
ventral plate; MS, median suture; G, gnathobases; Ch, chelicera; S, spines; M, metastoma; AOP, anterior opercular plate; MOP, median
opercular plate; POP, posterior opercular plate; GA, genital appendage; B, blattfu
¨sse.
Lamsdell et al. 1409
Published by NRC Research Press
mination, which may represent the primitive state within
Eurypterida. The specimen clearly links Brachyopterella
with the other basal rhenopterids Brachyopterus and Kiaer-
opterus; the widest point of the mesosoma is around the sec-
ond segment, and Brachyopterus,Brachyopterella, and
Leiopterella all display a narrow marginal rim to the cara-
pace, while Brachyopterus,Kiaeropterus, and Leiopterella
share a lack of cuticular sculpture. The dorsal structures of
the carapace of Leiopterella are not preserved, but it is
likely that the eyes were large and converging anteriorly as
in Brachyopterella and Kiaeropterus and that the ocelli were
situated within an ocellar area.
Leiopterella gen. nov. is clearly separated from Brachyop-
terus by the possession of crests rather than broad ridges on
its podomeres, a more derived rhenopterid character. It dif-
fers from Brachyopterella in the shape of the carapace and
the absence of an epistoma.
Discussion
The relationships of the Stylonuridae are poorly resolved,
with the family previously including several genera (e.g.,
Hallipterus) now known to belong in other families. The
new material of Pagea supports the relationships of the
Superfamily Stylonuroidea and its two constituent families,
the Parastylonuridae and the Stylonuridae, as proposed by
Lamsdell et al. (2010).
The holotype of Pagea sturrocki does not preserve the
dorsal structures of the carapace, and as such Waterston
(1962) reconstructed the dorsal anatomy based on Stylonurus
powriensis. The new specimens with their dorsal structures
preserved reveal just how accurate this assumption was; Sty-
lonurus and Pagea appear to be very closely related. Previ-
ously, Lamsdell et al. (2010) resolved them within a
paraphyletic grade, from the Parastylonuridae to Ctenopterus
Fig. 4. Cladogram of the relationships of the Stylonurina, as presented by Lamsdell et al. (2010), with the inclusion of the species discussed
herein. The single MPT (most parsimonious tree) was retrieved from analysis of the data set in Appendix A. Tree length = 126, CI (consis-
tency index) = 0.571, RI (retention index) = 0.729, RC (re-scaled consistency index) = 0.416. Jackknife support (20% resampling, 1000
repetitions) is shown above the nodes and is often higher than at the corresponding nodes in Lamsdell et al. (2010). The taxa representing
Eurypterina resolve as in the analysis of Lamsdell et al. (2010) and are represented in the figure by a single terminal.
1410 Can. J. Earth Sci. Vol. 47, 2010
Published by NRC Research Press
and Laurieipterus; however, the analysis herein resolves
them as sister-taxa (Fig. 4). Of the three species assigned to
Pagea,P. sturrocki, and P. symondsii are united by strong
vaulting of the carapace. Both are known from the Lochko-
vian of the UK (the former from Scotland, the latter from
Herefordshire), and may be synonyms. P. symondsii could
be a juvenile of P. sturrocki (length 65 cm), as the smaller
but otherwise identical carapace of P. symondsii indicates a
total length of 35 cm. If this were the case then P. symondsii
would have priority, but more specimens of both species
would need to be found before such issues of synonymy
can be resolved.
The Rhenopteridae were previously only known from Eu-
rope, and in the Devonian only from the Rheno-Hercynian
terrane of Germany. The discovery of Leiopterella gen.
nov. shows that this basal clade of stylonurines was more
geographically widespread than previously suggested (e.g.,
Tetlie 2007). Our analysis places Leiopterella as basal to
the Rhenopterinae, consisting of Rhenopterus and Alkenop-
terus (Fig. 4). The genera Brachyopterella and Kiaeropterus
themselves form a more basal clade of Silurian rhenopterids.
Brachyopterus is basal to both these clades, as befitting its
stratigraphic position in the Ordovician. The morphology of
the lateral eyes and postabdomen of Leiopterella are equivo-
cal; the lateral eyes may be large and converging anteriorly
as in the Silurian genera, while the postabdomen may be
caudal as in the Rhenopterinae. There is a clear progression
throughout rhenopterid evolution from broad carapaces nar-
rowest at their base (Brachyopterus,Brachyopterella,Leiop-
terella) to broad carapaces narrowest at their front
(Alkenopterus) to narrower carapaces narrow at the front
(Rhenopterus). Kiaeropterus is in some ways unusual in its
morphology, although several characters, including lateral
eye morphology and its probable possession of an epistoma
(Størmer 1934) place it as sister-taxon to Brachyopterella,
and it may represent an offshoot during the Silurian.
The first records of Pagea and a rhenopterid from Canada
offer insights into the palaeobiogeography of these groups.
Only one other unequivocal member of the Stylonuridae is
known from North America (Ctenopterus,fromtheSilurianof
New York (Clarke and Ruedemann 1912)), and so the discov-
ery of a more basal taxon (albeit in younger strata) begins to
link the European and American occurrences. The fact that the
Canadian records of Pagea are of the same age (Lochkovian)
as those from the UK suggests that some stylonurines may
have had a more cosmopolitan distribution than previously as-
sumed. The stratigraphic position of Leiopterella suggests that
it is part of a radiation from the early European rhenopterids;
the other basal rhenopterids are known from the Ordovician
and Silurian, and appear to go extinct by the Devonian with
only the North American genus and those of the Rheno-Hercy-
nian terrane surviving. The Stylonuridae and Rhenopteridae are
the most poorly understood stylonurine families, and any new
discoveries linked to these families are extremely important.
Ideally specimens of Leiopterella preserving the dorsal cara-
pace morphology and postabdomen would be required to fully
confirm its position within the Rhenopteridae. Although fur-
ther, more complete specimens of Stylonurus powriensis also
need to be described before its affinities can be confirmed, the
identification of Stylonurus-like characters in a species of
Pagea firmly links these enigmatic eurypterid taxa.
Acknowledgements
We thank Simon Powell (University of Bristol, Bristol,
UK) for photographing CMN 53570 and 53573, Andrew
Ross (National Museums of Scotland, Edinburgh, Scotland,
UK) for access to Stylonurus powriensis and for providing
pictures of Pagea sturrocki for comparative purposes, and
Paul Shepherd (British Geological Survey (BGS), Keyworth,
Nottingham, UK) for access to Pagea symondsii. Jisuo Jin
(The University of Western Ontario, London, Ontario, Can-
ada), David Rudkin (Royal Ontario Museum, Toronto, On-
tario, Canada) and an anonymous referee provided valuable
suggestions and comments during review that greatly im-
proved the manuscript. JCL acknowledges the Palaeonto-
graphical Society for a grant to investigate early stylonurine
evolution that allowed for museum visits.
References
Andrews, H.E., Brower, J.C., Gould, S.J., and Reyment, R.A. 1974.
Growth and variation in Eurypterus remipes De Kay. Bulletin of
the Geological Institutions of the University of Uppsala, 4: 81–
114.
Braddy, S.J. 2001. Eurypterid palaeoecology: palaeobiological, ich-
nological and comparative evidence for a ‘mass-moult-mate’ hy-
pothesis. Palaeogeography, Palaeoclimatology, Palaeoecology,
172(1–2): 115–132. doi:10.1016/S0031-0182(01)00274-7.
Braddy, S.J., and Dunlop, J.A. 2000. Early Devonian eurypterids
from the Northwest Territories of Arctic Canada. Canadian Jour-
nal of Earth Sciences, 37(8): 1167–1175. doi:10.1139/cjes-37-8-
1167.
Braddy, S.J., and Milner, A.R.C. 1998. A large arthropod trackway
from the Gaspe
´Sandstone Group (Middle Devonian) of eastern
Canada. Canadian Journal of Earth Sciences, 35(10): 1116–
1122. doi:10.1139/cjes-35-10-1116.
Briggs, D.E.G. 1979. Anomalocaris, the largest known Cambrian
arthropod. Palaeontology, 22: 631–664.
Broad, D.S., Dineley, D.L., and Miall, A.D. 1968. The Peel Sound
Formation (Devonian) of Prince of Wales and adjacent islands:
A preliminary report. Journal of the Arctic Institue of North
America, 21: 84–91.
Brusatte, S.L. 2010. Representing supraspecific taxa in hugher-le-
vel phylogenetic analyses: guidelines for palaeontologists. Pa-
laeontology, 53(1): 1–9. doi:10.1111/j.1475-4983.2009.00918.x.
Burmeister, H. 1843. Die Organisation der Trilobiten, aus ihren le-
benden Verwandten entwickelt; nebst systematische Uebersicht
aller Seitherbeschriebenen Arten. G. Reimer, Berlin.
Clarke, J.M., and Ruedemann, R. 1912. The Eurypterida of New
York. New York State Museum Memoirs. Vol. 14, pp. 1–439.
Copeland, M.J., and Bolton, T.E. 1960. The Eurypterida of Canada.
Geological Survey of Canada, Bulletin 60, pp. 13–48.
Copeland, M.J., and Bolton, T.E. 1985. Fossils of Ontario Part 3:
The eurypterids and phyllocarids. Royal Ontario Museum, Life
Sciences Miscellaneous Publications.
Diener, C. 1924. Fossilium Catalogus, I; Pars 25, Eurypterida. Ber-
lin.
Dineley, D.L. 1965. Notes of the scientific results of the University
of Ottawa expedition to Somerset Island, 1964. Journal of Arctic
Institute of North America, 18: 55–57.
Dineley, D. 1966. Geological studies in Somerset Island, University
of Ottawa expedition, 1965. Journal of Arctic Institute of North
America, 19: 270–277.
Dineley, D.L. 1994. Cephalaspids from the Lower Devonian of
Prince of Wales Island, Canada. Palaeontology, 37: 61–70.
Lamsdell et al. 1411
Published by NRC Research Press
Elliott, D.K. 1984. Siluro-Devonian fish biostratigraphy of the Ca-
nadian Arctic Islands. Proceedings of the Linnean Society of
New South Wales, 107: 197–209.
Greiner, H. 1972. Arthropod trace fossils in the Lower Devonian
Jacquet River Formation of New Brunswick. Canadian Journal
of Earth Sciences, 9: 1772–1777.
Gupta, N.S., Tetlie, O.E., Briggs, D.E.G., and Pancost, R.D. 2007.
The fossilization of eurypterids: a result of molecular transfor-
mation. Palaios, 22(4): 439–447. doi:10.2110/palo.2006.p06-
057r.
Jeram, A.J. 1996. Chelicerata from the Escuminac Formation. In
Devonian fishes and plants of Miguasha, Quebec, Canada. Edi-
ted by H.-P. Schultze and R. Cloutier. Verlag Dr Friedrich Pfeil,
Munich, pp. 103–111.
Kjellesvig-Waering, E.N. 1966. A revision of the families and gen-
era of the Stylonuracea (Eurypterida). Fieldiana. Geology, 14(9):
169–197.
Lamsdell, J.C., and Braddy, S.J. 2010. Cope’s Rule and Romer’s
theory: patterns of diversity and gigantism in eurypterids and
Palaeozoic vertebrates. Biology Letters, 6(2): 265–269. doi:10.
1098/rsbl.2009.0700. PMID:19828493.
Lamsdell, J.C., Braddy, S.J., and Tetlie, O.E. 2009. Redescription
of Drepanopterus abonensis (Chelicerata: Eurypterida: Stylonur-
ina) from the Late Devonian of Portishead, UK. Palaeontology,
52(5): 1113–1139. doi:10.1111/j.1475-4983.2009.00902.x.
Lamsdell, J.C., Braddy, S.J., and Tetlie, O.E. 2010. The systema-
tics and phylogeny of the Stylonurina (Arthropoda: Chelicerata:
Eurypterida). Journal of Systematic Palaeontology, 8: 49–61.
Plotnick, R.E., and Elliott, D.K. 1995. A Lower Devonian stylo-
nurid eurypterid from Arctic Canada. Journal of Paleontology,
69: 399–402.
Poschmann, M., and Tetlie, O.E. 2004. On the Emsian (Early De-
vonian) arthropods of the Rhenish Slate Mountains: 4. The eur-
ypterids Alkenopterus and Vinetopterus n. gen. (Arthropoda:
Chelicerata). Senckenbergiana lethaea, 84(1-2): 173–196.
doi:10.1007/BF03043470.
Rolfe, W.D.I., and Dzik, J. 2006. Angustidontus, a Late Devonian
pelagic predatory crustacean. Transactions of the Royal Society
of Edinburgh. Earth Sciences, 97(01): 75–96. doi:10.1017/
S0263593300001413.
Rudkin, D., Stott, C., Tetreault, D., and Rancourt, C. 1998. Ordovi-
cian and Silurian rocks and fossils of the southern Georgian Bay
area, Ontario. Canadian Paleontology Conference, Field Trip
Guidebook No. 7. Geological Association of Canada - Paleontol-
ogy Division, 37 p.
Selden, P.A. 1981. Functional morphology of the prosoma of Bal-
toeurypterus tetragonophthalmus (Fischer) (Chelicerata: Euryp-
terida). Transactions of the Royal Society of Edinburgh. Earth
Sciences, 72: 9–48.
Størmer, L. 1934. Merostomata from the Downtonian Sandstones
of Ringerike, Norway. Skrifter utgitt au Det Norske, Viddens-
kaps-Akademie i Oslo, 1933, No. 10.
Størmer, L. 1936. Eurypteriden aus dem Rheinischen Unterdevon.
Abhandlungen der Preußischen Geologischen Landesanstalt,
Vol. 175, pp. 1–74.
Størmer, L. 1951. A new eurypterid from the Ordovician of Mon-
tgomeryshire, Wales. Geological Magazine, 88(6): 409–422.
doi:10.1017/S001675680006996X.
Stott, C.A., Tetlie, O.E., Braddy, S.J., Nowlan, G.S., Glasser, P.L.,
and Devereux, M.G. 2005. A new eurypterid (Chelicerata) from
the Upper Ordovician of Manitoulin Island, Ontario, Canada.
Journal of Paleontology, 79(6): 1166–1174. doi:10.1666/0022-
3360(2005)079[1166:ANECFT]2.0.CO;2.
Swofford, D.L. 2003. PAUP*. Phylogenetic Analysis Using Parsi-
mony (*and Other Methods). Ver. 4. Sinauer Associates, Sun-
derland, Mass., USA.
Tetlie, O.E. 2007. Distribution and dispersal history of Eurypterida
(Chelicerata). Palaeogeography, Palaeoclimatology, Palaeoecol-
ogy, 252(3–4): 557–574. doi:10.1016/j.palaeo.2007.05.011.
Tetlie, O.E., Brandt, D.S., and Briggs, D.E.G. 2008. Ecdysis in sea
scorpions (Chelicerata: Eurypterida). Palaeogeography, Palaeo-
climatology, Palaeoecology, 265(3–4): 182–194. doi:10.1016/j.
palaeo.2008.05.008.
Tollerton, V.P., Jr. 1989. Morphology, taxonomy, and classification
of the order Eurypterida Burmeister, 1843. Journal of Paleontol-
ogy, 63: 642–657.
Tollerton, V.P., Jr. 1997. Eurypterids and associated fauna at Litch-
field, a classic locality in Herkimer County. 69th Annual Meet-
ing and Guidebook New York State Geological Association,
pp. 253–264.
Waterston, C.D. 1962. Pagea sturrocki gen. et sp. nov., a new eur-
ypterid from the Old Red Sandstone of Scotland. Palaeontology,
5: 137–148.
Young, G.A., Rudkin, D.M., Dobrzanski, E.P., Robson, S.P., and
Nowlan, G.S. 2007. Exceptionally preserved Late Ordovician
biotas from Manitoba, Canada. Geology, 35(10): 883–886.
doi:10.1130/G23947A.1.
Appendix A
Character list and matrix (Table A1) for the phylogenetic
analysis. Thirteen new characters (03–04, 47, 62–71) are in-
cluded in the analysis, along with the taxa Pagea plotnicki,
Pagea symondsii, and Leiopterella tetliei.
01. Antero-median carapace protrusion (0 = absent; 1 =
present).
02. Denticulate anterior margin of carapace (0 = absent; 1
= present).
03. Carapace marginal rim broad (0 = absent; 1 =
present).
04. Row of pustules along inside of marginal rim (0 = ab-
sent; 1 = present).
05. Prosomal posterolateral lobes (0 = absent; 1 =
present).
06. Prosoma quadrate (0 = absent; 1 = present).
07. Median ridge between lateral eyes (0 = absent; 1 =
present).
08. Circular plateau ornamentation anterior to median
ridge (0 = absent; 1 = present).
09. Position of median eyes on carapace (0 = median
third; 1 = anterior third).
10. Ocellar area. (0 = absent; 1 = present).
11. Lateral eye shape (0 = crescentic; 1 = expanded).
12. Palpebral lobe circular (0 = absent; 1 = present).
13. Lateral eyes converging and placed anteriorly on car-
apace (0 = absent; 1 = present).
14. Round lens overlying lateral eyes (0 = absent; 1 =
present).
15. Orbital ridges (0 = absent; 1 = present).
16. Transverse suture on ventral plates (0 = absent; 1 =
present).
17. Transverse suture curving back at midline (0 = absent;
1 = present).
18. Suture on ventral plates (0 = epistoma absent; 1 =
epistoma present).
1412 Can. J. Earth Sci. Vol. 47, 2010
Published by NRC Research Press
19. Rostral field (0 = absent; 1 = present).
20. Ventral plates widen anteriorly (0 = absent; 1 =
present).
21. Appendage III (0 = spiniferous with paired spines; 1 =
spiniferous with single spines).
22. Pairs of spines per podomere on prosomal appendage
III (0 = one pair; 1 = two or more pairs).
23. Prosomal appendage IV (0 = spiniferous; 1 = non-spi-
niferous).
24. Pairs of spines per podomere on prosomal appendage
IV (0 = one pair; 1 = two or more pairs).
25. Spines on prosomal appendage IV (0 = moveable
spines; 1 = both moveable and fixed spines; 2 = fixed
spines).
26. Blade-like structures on podomeres of anterior ap-
pendage (0 = absent; 1 = present).
27. Rachis (0 = absent; 1 = present).
28. Coxal laden (0 = absent; 1 = present).
29. Prosomal appendage V (0 = spiniferous; 1 = non-spi-
niferous).
30. Spines on prosomal appendage V reduced (0 = absent;
1 = present).
31. Prosomal appendage VI (0 = walking leg; 1 = swim-
ming leg).
32. Appendage VI reaching to pretelson (0 = absent; 1 =
present).
33. Shape of proximal podomere of appendage VI (0 =
narrow (length/width (L/W) > or = 2.0); 1 = expanded (L/
W < 2.0)).
34. Distal podomere margin of VI-6 modified (0 = absent;
1 = present).
35. ‘‘Ear’’ on coxa VI (0 = absent; 1 present).
36. Appendage VI showing lateral serrations (0 = absent;
1 = present).
37. Podomere 7a on sixth prosomal appendage (0 = ab-
sent; 1 = present).
38. Width of VI-7a (0 = narrow (<50% of width of VI-7);
1 = wide (>50%)).
39. Shape of VI-7a (0 = oval; 1 = triangular).
40. Longitudinal grooves on podomeres (0 = absent; 1 =
present).
41. Podomeres ridged (0 = absent; 1 = present).
42. Podomeres thicken distally (0 = absent; 1 = present).
43. Cleft metastoma (0 = absent; 1 = present).
44. Anterior margin of metastoma (0 = notch absent; 1 =
notch present).
45. Posterior margin of metastoma (0 = rounded; 1 = flat-
tened or recurved).
46. Paired tubercles on opisthosomal tergites 2–5 (0 = ab-
sent; 1 = present).
47. Opisthosoma narrower than carapace (0 = absent; 1 =
present).
48. Marginal rim on opisthosoma (0 = absent; 1 =
present).
49. Positive opisthosomal differentiation of third order
first segment (0 = absent; 1 = present).
50. Second tergite developed into round macrotergite (0 =
absent; 1 = present).
51. Preabdominal epimera (0 = absent; 1 = present).
52. Caudal postabdomen (0 = absent; 1 = present).
53. Lateral pleurae (0 = absent; 1 = present).
54. Pretelson elongated (0 = absent; 1 = present).
55. Pretelson postlaterally expanded (0 = absent; 1 =
present).
56. Dorsal pretelson lobes (0 = absent; 1 = present).
57. Telson shortened (0 = absent; 1 = present).
58. Telson elongate (0 = absent; 1 = present).
59. Dorsal median keel on telson (0 = absent; 1 =
present).
60. Paired, broad rounded ventral keels on telson (0 = ab-
sent; 1 = present).
61. Carapace ornament of large lunate scales surrounding
and pointing away from the central area and eyes. [0 = ab-
sent; 1 = present).
62. Row of large, tongue-shaped scales on posterior mar-
gin of opisthosomal segments (0 = absent; 1 = present].
63. Pustular ornamentation (0 = absent; 1 = present).
64. Acicular scales on opisthosoma (0 = absent; 1 =
present).
65. Podomere VI-5 (0 = half the width of VI-4; 1 = equal
width of VI-4).
66. Lateral carapace margin (0 = continuous; 1 =
stepped).
67. Carapace anterior (0 = rounded; 1 = angular).
68. Carapace vaulted (0 = absent; 1 = present).
69. Metasoma (0 = bulky; 1 = gracile).
70. Groove running across doublure (0 = absent; 1 =
present).
71. Carapace position of greatest width (0 = posterior
third; 1 = median third).
Lamsdell et al. 1413
Published by NRC Research Press
Table A1. Matrix used in the phylogenetic analysis.
Weinbergina opitzi 0000000000 00000000–0 0000000000 0010000--0
00—00000 1000000000 0000100000 0
Alkenopterus brevitelson 0010000000 00000????? ??????0?1- 00?0?00--0
10???00000 0100001000 000010001? 0
Brachyopterella pentagonalis 000000??01 001001111? ??1–?0?1- 0000000--0
10????00?? 0?????0?0? 0?00001010 1
Brachyopterus stubblefieldi 00000000?1 00000????? 1–00000?1- 00?0?00--0
000?000000 0000000000 000000000? 1
Ctenopterus cestrotus 010000001? 01000??11? 0101200?1- 01?0?00--0
00???00000 1?0???010? 0001100000 0
Cyrtoctenus wittebergensis 1000100000 00011????? ??00111??? ?00?00???1
01???00000 0000100001 010010000? 0
Drepanopterus abonensis 0011001000 00010100–1 001–1001- 0000000--1
0111–10000 0000000010 0010100000 0
‘‘Drepanopterus’’ bembycoides 00000000?0 000??0–10? ?????0001- 00?0?01010
0001000000 0000001000 0000100000 0
Drepanopterus pentlandicus 001?00?0?0 000??????? ??1–???1- 00?0?00--?
0111–10000 0000000010 0010100000 0
Hallipterus excelsior 000100110? 000111011? ?????0?0?? ??????????
?????????? 0????????? 1?00?010?0 0
Hardieopterus macrophthalmus 00000010?0 00000100–1 ??????0?00 0000?00--0
0101100100 00100100?? 1110100000 0
Hibbertopterus scouleri 0000101000 00010????1 ??0011011- 00?0000--0
0111–00000 0000000001 0100100000 0
Kiaeropterus cyclophthalmus 0000000001 00100????? ??????0?1- 00?0??0--0
10???00000 000??????0 0000?0001? ?
Kokomopterus longicaudatus 000000???? 0000?????1 0000000?01 00?0010--0
0101100100 0000000000 0100100000 0
Lamontopterus knoxae 000000???? ?????????? ??????0?01 00?0?00--0
01???00100 0000000000 ??0010000? 0
Laurieipterus elegans 0100000010 0100011111 0101200?1- 0?00000--0
0000100000 0?????01?? 00001100?0 0
Megarachne servinei 1000001000 0001?????? ??1–1011- 0???0????1
01????0011 ?????????? 000??000?? 0
Moselopterus ancylotelson 00000000?0 00000??0–0 000000001- 0010101000
0001000000 00000010?0 0000101001 0
Mycterops mathieui 10??00???? 00010????? ?????????? ??????????
???????01? ????0?0??? 0?0??010?? 0
Pagea sturrocki 000001???? 01001100–1 0101200?1- 01?0000--0
0000101?00 0001100010 0001111100 1
Parastylonurus ornatus 00000000?0 00000100–1 000000001- 0100000--0
0001100000 0001100010 0000100000 0
Rhenopterus diensti 0000000000 00000100–1 1–1–0001- 0000000--0
1001000000 0100001010 0011100011 0
Stylonurella spinipes 00000100?0 00000100–1 ?11000001- 0100000--0
00???01000 000??????? 0000111000 0
Stylonurus powriensis 00000110?0 01001?????0 ????????1- 01?0?00--0
00???00000 000000011 000110000? 0
Tarsopterella scotica 00000011?0 00001????? ?????????? ??????????
01???00000 001001000? 1100?0100? 0
Vinetopterus struvei 0000000000 00000????? ??????0??? 0010?0110?
0????00000 00001010?0 0?00100000 0
Woodwardopterus scabrosus 000000???? 000??????? ??1–10?1- 00?0?00--1
01????0011 000??0?0?1 000010000? 0
Eurypterus remipes 0000000000 100000–0-0 000000001- 1011101110
0001000000 0000100000 0000100000 0
Hughmilleria socialis 0000000000 100000–100 0000000000 1011101110
0001000000 0000000000 0000100000 0
Onychopterella augusti 00000000?0 ?0000????0 ??0000001- 1010101010
00???00000 0000?000?0 0000100000 0
1414 Can. J. Earth Sci. Vol. 47, 2010
Published by NRC Research Press
Pagea plotnicki 00000110?0 01001????? 11???00?1- 0??0?0???0
00???01000 0001110??? 000111100? 1
Pagea symondsii 00000110?0 01001??0–1 ?????????? ??????????
?????????? ?????????? 000?1111?0 1
Leiopterella tetliei 000000???? ?????100–1 ??100??01- 0?0000???0
10010?1000 ?????????? ??0?1000?1 1
Lamsdell et al. 1415
Published by NRC Research Press
