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Acta Palaeontologica Polonica 62 (x): xxx–xxx, 2017
Brief report
Acta Palaeontol. Pol. 62 (X): xxx–xxx, 2017 https://doi.org/10.4202/app.00361.2017
Aysheaia prolata from the Utah Wheeler Formation (Drumian,
Cambrian) is a frontal appendage of the radiodontan Stanleycaris
STEPHEN PATES, ALLISON C. DALEY, and JAVIER ORTEGA-HERNÁNDEZ
Ayshe aia pro lata, was descr ibed as the only lobopodian from
the Drumian (Cambrian) Wheeler Formation in Utah, USA,
and the sole representative of this genus besides the type
species Aysheaia pedunculata, from the Cambrian (Stage 5)
Stephen Formation, British Columbia. A redescription of
Aysheaia prolata reveals previously overlooked morpholog-
ical features, including segmental boundaries between pu-
tative lobopods, and curved terminal spines on the putative
anterior end. These observations undermine lobopodian
affinities of Aysheaia prolata, and instead we interpret this
specimen as an isolated radiodontan frontal appendage.
The presence of 11 podomeres, five of which possess elon-
gate and anteriorly recurved ventral blades with auxiliary
spines, together with shorter robust dorsal spines, identify
the specimen as Stanleycaris. This represents the first re-
port of Stanelycaris outside of the Cambrian Stage 5 thin
Stephen Formation in British Columbia, expanding its pa-
laeobiogeographic and stratigraphic range. Aysheaia is left
as a monotypic genus endemic to the Burgess Shale. The
Spence Shale luolishaniid Acinocrinus stichus is currently
the only lobopodian known from the Cambrian of Utah.
Introduction
Radiodontans, a diverse group of large nektonic predators,
are among the most recognizable faunal components in Lower
Palaeozoic Burgess Shale-type biotas (e.g., Daley et al. 2009,
2013a, b; Daley and Edgecombe 2014; Van Roy et al. 2015;
Cong et al. 2016; Zeng et al. 2017). Despite their fundamentally
soft-bodied construction, there is a comprehensive record of
radiodontan diversity owing to the preferential preservation
of their sclerotized frontal appendages (e.g., Caron et al. 2010;
Daley and Budd 2010; Daley and Peel 2010; Wang et al. 2013;
Lerosey-Aubril et al. 2014; Vinther et al. 2014). Recent work
has expanded the palaeobiogeographic and stratigraphic oc-
currence of radiodontan taxa previously known only from the
Cambrian (Stage 5) Burgess Shale in British Columbia, includ-
ing new reports from the Cambrian (Series 3) of Utah (Pates
et al. in press). Here we demonstrate that Aysheaia prolata
Robison, 1985, widely regarded for over 30 years as the only
lobopodian from the Wheeler Formation (Drumian), is actu-
ally a radiodontan frontal appendage, and discuss implications
for the known diversity of middle Cambrian radiodontans and
lobopodians from Utah, USA.
Institutional abbreviations.—KUMIP, University of Kansas
Natural History Museum, Lawrence, Kansas, USA; ROM,
Royal Ontario Museum, Toronto, Canad a; USNM, Smithsonian
Institution National Museum of Natural History, Washington
D.C., USA.
Other abbreviations.—Pn, podomere n; sag., sagittal; trans.,
transverse.
Material and methods
The only known specimen (KUMIP 153923) is housed at the
University of Kansas Natural History Museum. A Canon EOS
500D DSLR camera, with Canon EF-S 60 117 mm Macro
Lens, controlled for remote shooting with EOSUtility 2 was
used for photography. Photographs were taken wet, dry, under
cross-polarized and non-polarized light. Lengths and angles
were measured from photographs using ImageJ 2. Photoshop
CS6 was used to convert photographs to black and white and
manipulate colour channels.
Systematic palaeontology
Phylum Euarthropoda Lankester, 1904
Order Radiodonta Collins, 1996
Family Hurdiidae Vinther, Stein, Longrich, and
Harper, 2014
Genus Stanleycaris Caron, Gaines, Mángano,
Streng, and Daley, 2010
Type species: Stanleycaris hirpex Caron, Gaines, Mángano, Streng,
and Daley, 2010; Stephen Formation (Cambrian Series 3, Stage 5), near
Stanley Glacier (Kootenay National Park), British Columbia, Canada.
Remarks.—Stanleycaris was originally described from the thin
Stephen Formation near Stanley Glacier (Cambrian Stage 5),
British Columbia. 37 specimens of the type species, S. hirpex,
have been described: disarticulated assemblages including
frontal appendages, oral cones, and carapace material; no post
cephalic remains have yet been found.
Stratigraphic and geographic range.—Thin Stephen For ma tion
(Cambrian Series 3, Stage 5), British Columbia, Canada (Caron
et al. 2010); Wheeler Formation (Cambrian Series 3, Drumian),
Utah, USA (this study).
2 ACTA PALAEONTOLOGICA POLONICA 62 (X), 2017
Aysheaia prolata Robison, 1985 nomen dubium
= Stanleycaris sp.
Figs. 1A, 2, 3A.
1985 Aysheaia prolata sp. nov.; Robison 1985: 226–235, text-fig. 3.
1989 Aysheaia? prolata Robison, 1985; Dzik and Krumbiegel 1989:
175.
1995 Aysheaia? prolata Robison, 1985; Hou and Bergström 1995: 13.
1998 Aysheaia prolata Robison, 1985; Ramsköld and Chen 1998: 108,
134, 138–139, 143–144.
2001 Aysheaia? prolata Robison, 1985; Bergström and Hou 2001:
238, 245.
2004 Aysheaia? prolata Robison, 1985; Hou et al. 2004: 238.
2009 Aysheaia? prolata Robison, 1985; Whittle et al. 2009: 562.
2011 Aysheaia? prolata Robison, 1985; Ou et al. 2011: 587.
2
A
3
A4
A
A1
2
BB1
5mm 5mm
5mm 5mm
5mm 5mm
Fig. 1. A. Radiodontan euarthropod Stanleycaris sp., KUMIP 153923 from the Wheeler Formation (Cambrian Series 3, Drumian), Utah, USA; non-polarized
light (A1), cross-polarized light, red and yellow channels reduced (A2), cross polarized light (A3), cross-polarized light, red and yellow channels enhanced (A4).
B. Stanleycaris hirpex Caron, Gaines, Mángano, Streng, and Daley, 2010, ROM 59944 (holotype) from the Stephen Formation (Cambrian Series 3, Stage 5),
British Columbia, Canada; cross-polarized light (B1), black and white (B2).
Fig. 2. Explanatory drawing of radiodontan euarthropod Stanleycaris sp.,
KUMIP 153923 from the Wheeler Formation (Cambrian Series 3, Dru-
mian), Utah, USA. Hachure direction indicates lower sediment level. Dot-
ted lines indicate expected path of incomplete ventral blades.
P1 P4 P7 P11
P1
dorsal spines
sediment
layer
terminal
spines
auxiliary spines
ventral blades
5mm
BRIEF REPORT 3
2
A
A1B
CD
proximal distal
terminal spines
posterior
oral
papillae
anterior
P3 P4
podomere boundaries
podomere boundaries
P5 P6
ventral blades ventral blades
folds
lobopods
1mm 1mm
1mm
1mm
1mm
posterior
anterior
proximal distal proximal distal
Fig. 3. Comparison between terminal spines and vetral blades of Stanleycaris and oral papillae and lobopodous limbs of Aysheaia. A. Stanleycaris sp.,
KUMIP 153923 from the Wheeler Formation (Cambrian Series 3, Drumian), Utah, USA; anterior end showing recurved terminal spines (A1), ventral
blade (A2). B. Aysheaia pedunculata Walcott, 1911, USNM 189199 from the Stephen Formation (Cambrian Series 3, Stage 5), British Columbia, Can-
ada; anterior end showing anterior appendages and oral papillae. C, D. Stanleycaris hirpex Caron, Gaines, Mángano, Streng, and Daley, 2010 from the
Stephen Formation (Cambrian Series 3, Stage 5), British Columbia, Canada. C. ROM 59975 (paratype), ventral blade. D. USNM 83942, trunk section
and lobopods. Abbreviation: Pn, podomere n.
4 ACTA PALAEONTOLOGICA POLONICA 62 (X), 2017
2011 Aysheaia? prolata Robison, 1985; Gámez Vintaned et al. 2011:
211.
2015 Aysheaia? prolata Robison, 1985; Robison et al. 2015; 27, fig. 56.
2016 Aysheaia prolata Robison, 1985; Foster and Gaines 2016: 299,
303, 330, fig. 9H.
Material.—KUMIP 153923, isolated frontal appendage, pre-
served flattened in light grey shale collected from locality 114
of Robison and Richards (1981: 3), Utah, USA, approximately
100 m below the top of the Wheeler Formation (Cambrian
Series 3, Drumian; Robison 1985).
Description.—The appendage measures 26.5 mm in length
(sag.), and displays 11 podomeres, indicated by the preserva-
tion of serially repeated segmental boundaries. P1 differs from
the other podomeres in having a subrectangular outline (length
[sag.] ca. 7.0 mm; width [trans.] ca. 4.6 mm). P2 to P11 are
shorter (sag.) and wider (trans.). A layer of sediment between
P1 and P2 suggests that P1 has shifted forwards to cover the
posterior border of P2 (Fig. 2), making the precise dimensions
of P2 unclear. P3 to P8 are similar lengths (sag. ca. 2 mm). P3
to P6 maintain a stable width (trans. ca. 3.5 mm), whereas P7
to P11 taper distally (P7 ca. 3.2 mm; P11 ca. 2.2 mm). P9 to P11
are flexed laterally towards the rock surface, slightly overlap-
ping one another. It is not possible to measure the dimensions
of these podomeres owing to their orientation. The armature
consists of well-developed spinose ventral blades with auxil-
iary spines, and short dorsal spines. P1 lacks ornamentation
altogether. P2 to P6 possess ventral blades (“lobopods 1–5”
in Robison 1985: fig. 3.2), which emerge approximately per-
pendicular to the limb axis. The most complete of the blades
(on P4, Fig. 3A2), has a length (sag.) of approximately 8 mm
and possesses two distally-pointing auxiliary spines. The tip
curves sharply towards the distal end of the appendage, giving
the blade a crescent-shape. A ventral blade on P7 is approxi-
mately a third of the length (sag.) of the others, with no visible
auxiliary spines. Dorsal spines are observed on P4, P6, and P7.
The most complete dorsal spine is on P6; it has a subtriangular
outline with a robust base (“lobopod 1” in Robison 1985: fig.
3.2), projects at an angle of 71° from the main limb axis, and
shows no evidence for more than a single-point. P4 and P7
show poorly preserved dorsal spine bases (“anterior append-
age” in Robison 1985: fig. 3.2). Armature is absent from P8
to P10. P11 preserves two recurved terminal spines (Fig. 3A1;
“papillae?” in Robison 1985: fig. 3.2).
Remarks.—The recognition of podomere boundaries, together
with the occurrence of ventral, dorsal, and terminal spines,
support the reinterpretation of KUMIP 153923 as an isolated
radiodontan appendage. Robison’s (1985) original lobopodian
interpretation was largely based on the similar outline of this
B
A
5mm 5mm
Fig. 4. Lobopodian Aysheaia pedunculata Walcott, 1911, USNM 365608 from the Stephen Formation (Cambrian Series 3, Stage 5), British Columbia,
Canada; in cross-polarized light (A), cross-polarized light, red and yellow channels reduced (B).
B
Adorsal spines
proximal
P1
P2
P6
ventral blades
distal
ventral blades
dorsal spines
P2 P7
P6
terminal spine
5mm
5mm
proximal distal
Fig. 5. Radiodontan euarthropod Stanleycaris hirpex Caron, Gaines, Mán-
gano, Streng, and Daley, 2010 from the Stephen Formation (Cambrian
Series 3, Stage 5), British Columbia, Canada. A. ROM 59975 (paratype).
B. ROM 59976 (paratype). Abbreviation: Pn, podomere n.
BRIEF REPORT 5
specimen to Aysheaia pedunculata preserved in lateral view
(Fig. 4; Whittington 1978). Although A. pedunculata frequently
displays compaction wrinkles that may resemble segmental
boundaries (e.g., Fig. 3D; Ma et al. 2014: fig. 5B), these are gen-
erally restricted to the lobopodous limbs. The features identi-
fied as podomere boundaries in KUMIP 153923 occur along
the main axis of the fossil, rather than on the putative limbs.
Furthermore, the podomere boundaries cross the whole width
of the specimen, and are more widely spaced than annulations
on the trunk of A. pedunculata (Fig. 4). The putative lobopods
and oral papillae of A. prolata described by Robison (1985)
are best regarded as ventral blades and terminal spines respec-
tively. The ventral blades are curved and bear auxiliary spines
pointing to the anterior end, as also observed in in Stanleycaris
hirpex (compare Fig. 3A2 and 3C). The ventral blades lack
compaction wrinkles often preserved on limbs of A. peduncu-
lata (Figs. 3D, 4; Ma et al. 2014: f ig. 5B). The ter minal spi nes at
the anterior end of the specimen are short, recurved, and have
a sharp termination. This morphology is similar to that of the
spines in S. hirpex, and quite unlike the straight and less robust
oral papillae of A. pedunculata (compare Fig. 3A1 and 3B).
It should be noted that Robison (1985) studied the specimen
before the extent of radiodontan frontal appendage morpho-
logical diversity was known (e.g., Daley and Budd 2010; Caron
et al. 2010), and so lacked the appropriate context for correctly
interpreting KUMIP 153923.
Within the known diversity of radiodontan frontal append-
ages, the presence of five elongated ventral blades with auxil-
iary spines on P2 to P6, and differentiated distal podomeres,
support a more specific classification as a hurdiid (e.g., Daley
and Budd 2010; Daley et al. 2013a). Within hurdiids, KUMIP
153923 most closely resembles Stanleycaris hirpex (Figs. 1B,
5): both have 11 podomeres, including an elongated P1; long,
curved ventral blades with auxiliary spines on P2–P6; and a
distally tapering P7–P11. The only significant difference is that
the dorsal spine preserved on P6 of KUMIP 153923 appears to
be single-pointed, whereas dorsal spines of Stanleycaris from
Stanley Glacier are double-pointed (Figs. 1B, 5; Caron et al.
2010). The lack of a double-point may be the result of incom-
plete preservation in KUMIP 153923, as the size of the dorsal
spine relative to podomere width (trans.), robustness, and angle
relative to the dorsal surface of the podomere all conform to
Table 1. Comparison between Stanleycaris sp. and Stanleycaris hirpex.
Stanleycaris sp. Stanleycaris hirpex
Occurrence Wheeler Formation
Cambrian Series 3, Drumian Stephen Formation
Cambrian Series 3, Stage 5
Number of specimens 1 37
Number of podomeres 11 11
Length 26.5 mm 12.5–30.3 mm
Number of large ventral blades 5, on P2–P6 5, on P2–P6
Morphology of large ventral blades elongate, curved, with auxiliary spines elongate, curved, with auxiliary spines
Number of short ventral blades 1, on P7 1, on P7
Number of dorsal spines evidence for dorsal spines on P4, P6, P7, but dorsal
surface poorly preserved 9, on P2–P10
Morphology of dorsal spines robust, single pointed (?) robust, double pointed
Angle of projection of dorsal spines 71°, for dorsal spine on P6 45–90°
Morphology of terminal spines recurved, pointed recurved, pointed
Reference this study Caron et al. 2010
Table 2. Diversity of Cambrian radiodontans from Canada and Utah. A, appendage; C, carapace element; O, oral cone; P, post cephalic remains.
Burgess Shale (Stage 5) Stanley
Glacier
(Stage 5)
Spence Shale
(Stage 5)
Wheeler
Formation
(Drumian)
Marjum
Formation
(Drumian)
Weeks
Formation
(Guzhangian)
Anomalocaris canadensis A, C, O, P A
Anomalocaris sp. PP A
Hurdia victoria A, C, O, P A, C A, C, O
Hurdia triangulata A, C, O, P
Hurdia indet. sp. C
Caryosyntrips serratus A, C
Peytoia nathorsti A, O, P A, O O, P
Amplectobelua stephenensis A
Stanleycaris hirpex A, C, O
Stanleycaris sp. A
References Daley et al. 2009, 2013a, b;
Daley and Budd 2010;
Daley and Edgecombe 2014
Caron et al.
2010
Briggs et al.
2008; Pates et
al. in press
Briggs et al. 2008;
Pates et al. in
press; this study
Pates et al.
in press Lerosey-Aubril
et al. 2014
6 ACTA PALAEONTOLOGICA POLONICA 62 (X), 2017
the morphology of dorsal spines in Stanleycaris from Stanley
Glacier (Figs. 1B, 5). Additionally KUMIP 153923 fits within
the size-range described for Stanley Glacier specimens (12.5–
30.3 mm length [sag.]).
KUMIP 153923 differs from Hurdia frontal appendages in
the possession of 11 podomeres and more than one terminal
spine; Hurdia usually displays nine podomeres (rarely 10 or
11) and only one terminal spine (Daley et al. 2013a). KUMIP
153923 differs from Peytoia frontal appendages in the pres-
ence of a small ventral spine on P7; Peytoia displays no small
ventral spines (Daley et al. 2013a). Furthermore, KUMIP
153923 has a large dorsal spine which projects at a 71° angle to
the surface of P6, contrasting with the smaller, more inclined,
dorsal spines of both Hurdia and Peytoia appendages (Daley
et al. 2013a).
Aysheaia prolata should be considered a nomen dubium
due to the lack of distinguishing characters. As the incom-
plete preservation of KUMIP 153923 precludes a more detailed
comparison with the type material of Stanleycaris hirpex
(Figs. 1B, 5; Caron et al. 2010), we regard KUMIP 153923 as
Stanleycaris sp. (see Table 1 for comparison between the two
species). Additional material from the Wheeler Formation is
necessary to determine if the presence of single-pointed dorsal
spines in Stanleycaris sp. is a legitimate morphological feature
or a preservational artefact.
Concluding remarks
The recognition of KUMIP 153923 as a radiodontan frontal
appendage directly impacts the known diversity of these extinct
organisms for the lower Palaeozoic of Laurentia. Stanleycaris
can now be added to the list of radiodontan taxa have been
reported from the Cambrian (Series 3) of Utah and Canada
(Table 2). Peytoia nathorsti and Hurdia victoria (Briggs
et al. 2008; Pates et al. in press) are known in both regions
from frontal appendages, mouthparts, and carapace material.
Anomalocaris has also been described from post cephalic re-
mains in both the Spence Shale and Wheeler Formation (Briggs
et al. 2008), and isolated frontal appendages in the younger
(Guzhangian) Weeks Formation (Lerosey-Aubril et al. 2014).
The Wheeler Formation specimen is the youngest stratigraphic
occurrence of Stanleycaris, expanding its temporal range from
the Bathyuriscus–Elrathina Zone to the Ptychagnostus atavus
Zone.
Aysheaia prolata is here shown to be an invalid lobopodian
taxon, reducing the known diversity of these organisms for the
Cambrian of Laurentia. For over three decades, A. prolata was
regarded as the first lobopodian to be discovered from the nu-
merous Cambrian (Series 3) Konservat-Lagerstätten exposed
in Utah (Robison 1985) and was widely referenced as such in
subsequent studies (e.g., Dzik and Krumbiegel 1989; Hou and
Bergström 1995; Ramsköld and Chen, 1998; Bergström and
Hou 2001; Hou et al. 2004; Whittle et al. 2009; Ou et al. 2011;
Gámez Vintaned et al. 2011; Robison et al. 2015; Foster and
Gaines 2016). Our reappraisal of KUMIP 153923 leaves the
luolishaniid Acinocricus stichus (Conway Morris and Robison
1988) from the Spence Shale as the only Cambrian lobopodian
currently known from the USA (Ramsköld and Chen 1998;
García-Bellido et al. 2013; Yang et al. 2015).
Acknowledgements.—Bruce S. Lieberman and Paul A. Selden (KU-
MIP) provided access to the facilities and use of photographic equip-
ment, respectively. We thank Greg D. Edgecombe (Natural History
Museum, London, UK) and an anonymous reviewer for their valuable
comments and suggested improvements. SP was funded by a Palaeon-
tological Association Sylvester-Bradley Award (PA-SB201503) and is
supported by an Oxford-St Catherine’s Brade-Natural Motion Schol-
arship. ACD was funded by the Oxford University Museum of Natural
History. JOH is supported by a Herchel Smith Postdoctoral Fellowship
in Biological Sciences held at the Department of Zoology, University
of Cambridge.
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Stephen Pates [stephen.pates@zoo.ox.ac.uk], Department of Zoology, University of Oxford, Oxford, OX1 3PS, UK.
Allison C. Daley [allison.daley@unil.ch], Institute of Earth Sciences, University of Lausanne, Géopolis, CH-1015, Lausanne, Switzerland.
Javier Ortega-Hernández [jo314@cam.ac.uk], Department of Zoology, Downing Street, University of Cambridge, Cambridge, CB2 3EJ, UK.
Received 8 March 2017, accepted 11 May 2017, available online 14 August 2017.
Copyright © 2017 S. Pates et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License (for details please
see http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original
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