The Burgess Shale

Tokummia katalepsis

Tokummia katalepsis, paratype, ROMIP 63826

Taxonomy:

Kingdom: 3D Animation
Phylum: 3D Animation
Higher Taxonomic assignment: Hymenocarines, Family Protocarididae (Miller 1889).
Species name: Tokummia katalepsis
Remarks:

Hymenocarines were early arthropods with bivalved carapaces and mandibles, forming the bulk of the first mandibulates (represented today by myriapods, crustaceans and insects) (Aria & Caron 2017; Vannier et al. 2018). Tokummia was a close relative of Branchiocaris, both grouped within the eponymous family Protocarididae Miller, 1889—one of the oldest formal taxa from the Burgess Shale. The relationship of Protocarididae within hymenocarines, as well as the relative placement of hymenocarines within early mandibulates is still under investigation (Aria 2022; Izquierdo-López & Caron 2022).

Described by: Aria and Caron
Description date: 2017
Etymology:

Tokummia — from Tokumm Creek, a river of the Kootenay area, in British Columbia, running through Marble Canyon, near the outcrop where the fossil was first found.

katalapsis — from the Greek, meaning “seizing, grasping,” by reference to the well-developed pincers of the animal.

Type Specimens: Holotype ROMIP 63823; paratypes ROMIP 63014, 63081, 63824–63827, 63736 (7 specimens), in the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: none.
Other deposits: none.

Age & Localities:

Age:
Middle Cambrian, Wuliuan Stage, upper part of the Burgess Shale Formation (around 507 million years old).
Principal localities:

The Marble Canyon and Tokumm Creek areas of the Burgess Shale, British Columbia.

History of Research:

Brief history of research:

Tokummia was discovered during the original excavation of the Marble Canyon locality in 2012, along Yawunik and other taxa characteristic of this area. Additional specimens were later discovered during quarrying operations and along Tokumm Creek. Tokummia’s description was published in 2017: Tokummia’s size and quality of preservation helped identify mandibles and other diagnostic traits of mandibulates. Mandibles were also identified in Branchiocaris in the same study. This study partially rehabilitated original interpretations by Derek Briggs recognizing mandibulate affinities of Cambrian bivalved arthropods (hymenocarines) (Briggs 1992) but were not without their issues, notably that of the presence of an intercalary segment (e.g. Edgecombe 2017). However, research on hymenocarines has since been supportive of the mandibulate affinity of these arthropods (Vannier et al. 2018; Izquierdo-López & Caron 2022). Tokummia therefore remains central to our modern understanding of early arthropod evolution as a whole (Aria 2022).

Description:

Morphology:

Like other protocaridids, Tokummia’s long, tubular, multisegmented body is largely enclosed in a broad bivalved carapace with ample, lobate corners. Small processes are present medially at the front and rear of both valves. Eyes are very reduced or absent. The very front of the animal bears a bilobed organ covered by triangular sclerite. A pair of short, stout, multisegmented antennules are the most anterior appendages. The next pair of appendages are large, round mandibles, followed by modified appendages identified as maxillules and maxillae. The first pair of thoracic limbs are very large pincers projecting at the front of the animal, and therefore called maxillipeds. Trunk limbs are composed of well-developed walking legs ending in strong claws, and of lobate flaps that get much larger starting with trunk limb pair 9. There is a total of about 50 limb pairs in the trunk, one for each segment, which gradually decrease in size towards the back. Some tergites are fused at the back of the animal, forming a plate, and the tailpiece is a pair of caudal rami, typical of mandibulates.

Abundance:

The original description was based on 21 specimens (Aria & Caron 2017), but this count has so far doubled (Nanglu et al. 2020). Tokummia is a signature taxon of both the Marble Canyon quarry and the Tokumm sites.

Maximum Size:
About 15 cm.

Ecology:

Life habits: 3D Animation
Feeding strategies: 3D Animation
Ecological Interpretations:

The combination of large pincers and strong walking appendages in Tokummia suggests it was a nektobenthic predator. However, as in Branchiocaris and Protocaris, the absence of distinct eyes in the fossils, implying they were either very reduced or absent, indicates that the predatory lifestyle of Tokummia and other Protocarididae had its own specificity. Protocaridids either relied more heavily on their other sensory organs or were perhaps more passive predators.

References:

  • ARIA, C. 2022. The origin and early evolution of arthropods. Biological Reviews, 97, 1786–1809.
  • ARIA, C. and CARON, J. B. 2017. Burgess Shale fossils illustrate the origin of the mandibulate body plan. Nature, 545, 89–92.
  • BRIGGS, D. E. G. 1992. Phylogenetic significance of the Burgess Shale crustacean Canadaspis. Acta Zoologica, 73, 293–300.
  • EDGECOMBE, G. D. 2017. Palaeontology: The cause of jaws and claws. Current Biology, 27, R796–R815.
  • IZQUIERDO-LÓPEZ, A. and CARON, J.-B. 2022. The problematic Cambrian arthropod Tuzoia and the origin of mandibulates revisited. Royal Society Open Science, 9.
  • MILLER, S. A. 1889. North American geology and palaeontology for the use of amateurs, students and scientists. Western Methodist Book Concern, Cincinnati.
  • NANGLU, K., CARON, J.-B. and GAINES, R. R. 2020. The Burgess Shale paleocommunity with new insights from Marble Canyon, British Columbia. Paleobiology, 46, 58–81.
  • VANNIER, J., ARIA, C., TAYLOR, R. S. and CARON, J. B. 2018. Waptia fieldensis Walcott, a mandibulate arthropod from the middle Cambrian Burgess Shale. Royal Society Open Science, 5:172206.
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Titanokorys gainesi

Titanokorys gainesi, holotype ROMIP 65168

Taxonomy:

Kingdom: 3D Animation
Phylum: 3D Animation
Higher Taxonomic assignment: Order Radiodonta, Family Hurdiidae
Species name: Titanokorys gainesi
Remarks:

With its single pair of jointed frontal appendages, lateral swimming flaps, and circular mouth structure, Titanokorys possesses all the hallmarks of Radiodonta, part of the stem group to the true arthropods which also includes the iconic Anomalocaris (Collins 1996). The frontal appendages with comb or rake-like inner spines are characteristic of the radiodont family Hurdiidae. Phylogenetic analysis has found it to be closely related to Cambroraster from the Burgess Shale and Zhenghecaris from the Chengjiang deposit, which share similarities in carapace shape and a large number of finely-spaced spines on the appendages (Caron and Moysiuk 2021).

Described by: Caron and Moysiuk
Description date: 2021
Etymology:

Titanokorys – from Titans, a group of powerful Greek deities of great sizes, in reference to the large size of the central carapace and from the Greek word Korys meaning helmet.

gainesi – after Robert R. Gaines, Professor of Geology at Pomona College, who was instrumental in the co-discovery of the Marble Canyon fossil deposit in 2012.

Type Specimens: Holotype ROMIP 65415; Paratypes ROMIP 65168, 65741, 65748, and 65749, at the Royal Ontario Museum.
Other species:

Burgess Shale and vicinity: None
Other deposits: None

Age & Localities:

Age:
Middle Cambrian, Wuliuan Stage, upper part of the ‘thick’ Stephen Formation (Burgess Shale) (around 507 million years old).
Principal localities:

Marble Canyon and Mount Whymper / Tokumm Creek, Kootenay National Park, British Columbia.

History of Research:

Brief history of research:

Several specimens of Titanokorys were discovered at the Marble Canyon and North Tokumm sites in Kootenay National Park in 2014 and 2018. Because of their distinctive shape, large size, and resemblance to the smaller Cambroraster (nicknamed “spaceship”), the head carapaces were nicknamed the “mothership.” The genus and species were formally described in 2021 (Caron and Moysiuk 2021).

Description:

Morphology:

The defining feature of Titanokorys gainesi is its large dorsal carapace. This is roughly elliptical in overall shape. Frontally this carapace has a small spine flanked by a pair of blunt lobes. The rear sides of the carapace are developed into short, wing-like projections. Each “wing” has a small spine along its inner margin. The rear central part of the carapace extends into a bilobate projection. Between the lateral “wings” and bilobate projection are notches that presumably accommodated the eyes. On the underside, the head is protected by two additional plates, shaped like elongate paddles and joined together at the front by their narrow ends, each of which bears a stout, downward-directed spine. All three plates are covered in longitudinal rows of small bumps. A circular, tooth-lined jaw and a pair of jointed frontal appendages with five long, curving, rake-like inner spines are located on the underside, near the front of the head. The body bears rows of stacked gill blades.

Abundance:

Titanokorys is rare in Kootenay National Park, being known from just twelve specimens. Only disarticulated frontal appendages, mouthparts, carapace elements, and gills are known.

Maximum Size:
About 500 mm.

Ecology:

Life habits: 3D Animation
Feeding strategies: 3D Animation
Ecological Interpretations:

Like other hurdiids, Titanokorys shows adaptations to sweep feeding. Specifically, the rake-like inner spines on its stout frontal appendages form a rigid basket-like apparatus of spines surrounding the mouth, which could have functioned to disturb the sediment, sift out burrowing organisms, and move them into the mouth for further processing. Compared to related hurdiids like Hurdia and Stanleycaris, the particularly finely-spaced, strong, hooked secondary spines on the inner spines could have enabled capture of minute benthic organisms, although larger prey may also have been consumed. As the largest animal known from the Marble Canyon and Tokumm communities, Titanokorys would have been at the top of the food chain. Titanokorys shared the environment with the slightly smaller Cambroraster, which probably employed a similar mode of feeding, although body size differences may have entailed distinct prey size niches (Moysiuk and Caron 2019; Caron and Moysiuk 2021). Respiration would have been accomplished primarily through the rows of gill blades on the body (Daley et al. 2013).

References:

  • CARON, J.-B. and MOYSIUK, J. 2021. A giant nektobenthic radiodont from the Burgess Shale and the significance of hurdiid carapace diversity. Royal Society Open Science, 8: 210664.
  • COLLINS, D. 1996. The “evolution” of Anomalocaris and its classification in the arthropod class Dinocarida (nov.) and order Radiodonta (nov.). Journal of Paleontology, 70: 280–293.
  • DALEY, A. C., BUDD, G. E. and CARON, J.-B. 2013. Morphology and systematics of the anomalocaridid arthropod Hurdia from the Middle Cambrian of British Columbia and Utah. Journal of Systematic Palaeontology, 11: 743–787.
  • MOYSIUK, J. and CARON, J.-B. 2019. A new hurdiid radiodont from the Burgess Shale evinces the exploitation of Cambrian infaunal food sources. Proceedings of the Royal Society B, 286: 20191079.
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Cambroraster falcatus

Cambroraster falcatus, isolated H-element ROMIP 65316

Taxonomy:

Kingdom: 3D Animation
Phylum: 3D Animation
Higher Taxonomic assignment: Order Radiodonta, Family Hurdiidae
Species name: Cambroraster falcatus
Remarks:

With its single pair of jointed frontal appendages, lateral swimming flaps, and circular mouth structure, Cambroraster possesses all the hallmarks of Radiodonta, part of the stem group to the true arthropods which also includes the iconic Anomalocaris (Collins 1996). The frontal appendages with comb or rake-like inner spines are characteristic of the radiodont family Hurdiidae. Phylogenetic analysis found it to be closely related to Titanokorys from the Burgess Shale and Zhenghecaris from the Chengjiang deposit, which share similarities in carapace shape and a large number of finely-spaced spines on the appendages (Caron and Moysiuk 2021).

Described by: Moysiuk and Caron
Description date: 2019
Etymology:

CambrorasterCambro, for Cambrian; raster, for the rake-like morphology of the inner spines on the frontal appendages.

falcatus – meaning sickle-shaped, but more specifically in reference to the dorsal carapace’s resemblance to the fictional Millennium Falcon starship in the Star Wars franchise.

Type Specimens: Holotype ROMIP 65078; Paratypes ROMIP 65079, 65081, 65083, 65084, 65092, at the Royal Ontario Museum.
Other species:

Burgess Shale and vicinity: None

Other deposits: Cambroraster sp. from the early Cambrian Chengjiang biota (Liu et al. 2020); Cambroraster cf. C. falcatus from the mid-Cambrian Mantou Formation of north China (Sun et al. 2020).

Age & Localities:

Age:
Middle Cambrian, Wuliuan stage, Burgess Shale Formation (around 507 million years old).
Principal localities:

Marble Canyon and Mount Whymper / Tokumm Creek, Kootenay National Park, British Columbia.

History of Research:

Brief history of research:

Several specimens of Cambroraster were discovered at the Marble Canyon and North Tokumm sites in Kootenay National Park in 2014. Because of their distinctive shape, the head carapaces were nicknamed the “spaceship.” Isolated frontal appendages were initially tentatively assigned to the genus Hurdia (Caron et al. 2014). The affinities of Cambroraster were not well-understood until further finds of abundant material at North Tokumm in 2018. The genus and species were formally described in 2019 (Moysiuk and Caron 2019). 3D digital modeling of an appendage of Cambroraster found it to have the lowest potential degree of appendage articulation of any of the studied radiodontans (de Vivo et al. 2021).

Description:

Morphology:

The defining feature of Cambroraster falcatus is its large, horseshoe-shaped dorsal carapace. This carapace is rounded frontally and projects along the rear sides into elongate wing-like projections lined along their margins with small spines. The rear central part of the carapace extends into a bilobate projection. Between the lateral “wings” and central projection are deep notches that accommodate the elliptical eyes, which are directed upwards. On the underside, the head is protected by two additional plates, shaped like elongate paddles and joined together at the front by their narrow ends. A circular, tooth-lined jaw and a pair of jointed frontal appendages with five long, curving, strong rake-like inner spines are located on the underside, near the front of the head. The body is stout, shorter than the dorsal carapace, and composed of 11 segments bearing rows of stacked gill blades and short lateral swimming flaps plus four short tail blades.

Abundance:

Cambroraster is abundant in Kootenay National Park, being known from over 100 specimens. It is particularly abundant around the North Tokumm locality, and may occur by the dozens on certain bedding planes, suggesting gregarious mass moulting behaviour. Rarer remains are known from Marble Canyon and single, isolated carapace fragments are known from Mount Stephen and Mount Field.

Maximum Size:
About 300 mm

Ecology:

Life habits: 3D Animation
Feeding strategies: 3D Animation
Ecological Interpretations:

Like other hurdiids, Cambroraster shows adaptations to sweep feeding. Specifically, the stout and rigid frontal appendages are ill-suited to grasping large, mobile prey (de Vivo et al. 2021). Instead, the rake-like inner spines on the appendages form a rigid, basket-like apparatus of spines surrounding the mouth. Sideways movements of the appendages could have disturbed the sediment, sifting out burrowing organisms, and transferring them to the mouth for further processing (Moysiuk and Caron 2019). Compared to related hurdiids like Hurdia and Stanleycaris, the particularly numerous and finely-spaced, strong, hooked secondary spines on the inner spines could have enabled capture of minute benthic organisms, although larger prey may also have been consumed. As one of the largest animals in the Marble Canyon and Tokumm communities, Cambroraster would have been near the top of the food chain. The broad dorsal carapace, upward facing eyes, and stubby body suggest it spent most of its time near the sea floor (Moysiuk and Caron 2019). As in other radiodontans, swimming was facilitated by undulation of the lateral flaps while respiration would have been accomplished primarily through the rows of gill blades on the body (Usami 2006; Daley et al. 2013).

References:

  • CARON, J.-B. and MOYSIUK, J. 2021. A giant nektobenthic radiodont from the Burgess Shale and the significance of hurdiid carapace diversity. Royal Society Open Science, 8: 210664.
  • CARON, J.-B., GAINES, R. R., ARIA, C., MÁNGANO, M. G. and STRENG, M. 2014. A new phyllopod bed-like assemblage from the Burgess Shale of the Canadian Rockies. Nature communications, 5: 1–6.
  • COLLINS, D. 1996. The “evolution” of Anomalocaris and its classification in the arthropod class Dinocarida (nov.) and order Radiodonta (nov.). Journal of Paleontology, 70: 280–293.
  • DALEY, A. C., BUDD, G. E. and CARON, J.-B. 2013. Morphology and systematics of the anomalocaridid arthropod Hurdia from the Middle Cambrian of British Columbia and Utah. Journal of Systematic Palaeontology, 11: 743–787.
  • LIU, Y., LEROSEY-AUBRIL, R., AUDO, D., ZHAI, D., MAI, H. and ORTEGA-HERNÁNDEZ, J. 2020. Occurrence of the eudemersal radiodont Cambroraster in the early Cambrian Chengjiang Lagerstätte and the diversity of hurdiid ecomorphotypes. Geological Magazine, 157: 1200–1206.
  • MOYSIUK, J. and CARON, J.-B. 2019. A new hurdiid radiodont from the Burgess Shale evinces the exploitation of Cambrian infaunal food sources. Proceedings of the Royal Society B, 286: 20191079.
  • SUN, Z., ZENG, H. and ZHAO, F. 2020. Occurrence of the hurdiid radiodont Cambroraster in the middle Cambrian (Wuliuan) Mantou Formation of North China. Journal of Paleontology, 94: 881–886.
  • USAMI, Y. 2006. Theoretical study on the body form and swimming pattern of Anomalocaris based on hydrodynamic simulation. Journal of Theoretical Biology, 238: 11–17.
  • DE VIVO, G., LAUTENSCHLAGER, S. and VINTHER, J. 2021. Three-dimensional modelling, disparity and ecology of the first Cambrian apex predators. Proceedings of the Royal Society B, 288.
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Yuknessia simplex

3D animation of Yuknessia simplex.
© Phlesch Bubble

Taxonomy:

Kingdom: 3D Animation
Phylum: 3D Animation
Higher Taxonomic assignment: Non applicable
Species name: Yuknessia simplex
Remarks:

Walcott (1919) considered Yuknessia as a green alga, a view shared by Conway Morris and Robison (1988). However, no revision of the type material from the Burgess Shale has been published since its original description and its affinities remain uncertain.

Described by: Walcott
Description date: 1919
Etymology:

Yuknessia – from Yukness Mountain (2,847m), a Peak in Yoho National Park, east of the Burgess Shale.

simplex – from the Latin simplex, meaning “simple,” in reference to the simple morphology of this alga.

Type Specimens: Holotype –USNM35406 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none

Other deposits: Yuknessia sp. from the Lower Cambrian Niutitan Formation in China (Yang et al., 2003).

Age & Localities:

Age:
Middle Cambrian, Bathyuriscus-Elrathina Zone to Ptychagnostus punctuosus Zone (approximately 505 million years ago).
Principal localities:

Burgess Shale and vicinity: The Walcott Quarry on Fossil Ridge and the Trilobite Beds on Mount Stephen.

Other deposits: Y. simplex is known from the Middle Cambrian Spence Shale and the Marjum and Wheeler Formations in Utah (Conway Morris and Robison, 1988).

History of Research:

Brief history of research:

This genus was described by Charles Walcott (1919) as a possible green alga. However, like all the algae from the Burgess Shale, it awaits a modern redescription (see Dalyia). Conway Morris and Robison (1988) described specimens of this species from several Utah deposits.

Description:

Morphology:

This alga has long branches emerging from a short but wide hollow stem covered of small conical elements or plates. The plates were the attachment sites of the branches. The branches show strong similarities with Dalyia and suggest the two species might be synonymous, with Yuknessia representing the main stem structure of the Dalyia branches.

Abundance:

Yuknessia is very rare and represents only 0.04% of the Walcott Quarry community (Caron and Jackson, 2008).

Maximum Size:
30 mm

Ecology:

Life habits: 3D Animation
Feeding strategies: 3D Animation
Ecological Interpretations:

The wide stem suggests this species was attached to the sea floor within the photic zone rather than being free floating.

References:

CARON, J.-B. AND D. A. JACKSON. 2008. Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology, 258: 222-256.

CONWAY MORRIS, S. AND R. A. ROBISON. 1988. More soft-bodied animals from the Middle Cambrian of Utah and British Columbia. University of Kansas Paleontological Contributions, 122 p.

WALCOTT, C. 1919. Cambrian Geology and Paleontology IV. Middle Cambrian Algae. Smithsonian Miscellaneous Collections, 67(5): 217-260.

YANG, R., W. ZHANG, L. JIANG AND H. GAO. 2003. Chengjiang biota from the Lower Cambrian Niutitang Formation, Zunyi County, Guizhou Province, China. Acta Palaeontologica Sinica, 77: 145-150.

Other Links:

None

Testing this Change

Yohoia tenuis

3D animation of Yohoia tenuis.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: 3D Animation
Phylum: 3D Animation
Higher Taxonomic assignment: Unranked clade Megacheira? (stem group arthropods)
Species name: Yohoia tenuis
Remarks:

Yohoia was originally considered to be a branchiopod crustacean (Walcott, 1912; Simonetta, 1970), but was also described as being closely related to the chelicerates (Briggs and Fortey, 1989; Wills et al., 1998; Cotton and Braddy, 2004). Other analyses suggest that Yohoia belongs in the group of “great appendage” arthropods, the Megacheira, together with LeanchoiliaAlalcomenaeus and Isoxys (Hou and Bergström, 1997; Budd, 2002). The megacheirans have been suggested to either be stem-lineage chelicerates (Chen et al. 2004; Edgecombe, 2010), or stem-lineage euarthropods (Budd, 2002).

Described by: Walcott
Description date: 1912
Etymology:

Yohoia – from the Yoho River, Lake, Pass, Glacier, Peak (2,760 m) and Park, British Columbia, Canada. “Yoho” is a Cree word expressing astonishment.

tenuis – from the Latin tenuis, “thin,” referring to its slender body.

Type Specimens: Lectoype –USNM57699 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

Age:
Middle Cambrian, Bathyuriscus-Elrathina Zone (approximately 505 million years ago).
Principal localities:

The Walcott, Raymond and Collins Quarries on Fossil Ridge.

History of Research:

Brief history of research:

Yohoia was first described by Walcott (1912), who designated the type species Y. tenuis based on six specimens, and a second species, Y. plena, based on one specimen. Additional specimens of Y. tenuis were described by Simonetta (1970), and a major redescription of Yohoia tenuis was then undertaken by Whittington (1974), based on over 400 specimens of this species. Whittington (1974) invalidated Y. plena, upgrading it to its own genus, Plenocaris plena, leaving Y. tenuis as the only species of YohoiaYohoia has since been included in several studies on arthropod phylogeny and evolution (e.g., Briggs and Fortey, 1989; Hou and Bergström, 1997; Wills et al., 1998; Budd, 2002; Chen et al., 2004; Cotton and Braddy, 2004).

Description:

Morphology:

The body of Yohoia consists of a head region encapsulated in a cephalic shield and 14 body segments, ending in a paddle-shaped telson. The dorsal head shield is roughly square and extends over the dorsal and lateral regions of the head. There is a pair of great appendages at the front of the head. Each appendage consists of two long, thin segments that bend like an elbow at their articulation, with four long spines at the tip. Three pairs of long, thin, segmented appendages project from beneath the head shield behind the great appendages.

The body behind the head consists of ten segments with tough plates, or tergites, that extend over the back and down the side of the animal, ending in backward-facing triangular points. The first of these body segments may have an appendage that is segmented and branches into two (biramous), with a segmented walking limb bearing a flap-like extension. The following nine body segments have only simple flap-shaped appendages fringed with short spines or setae. The next three body segments have no appendages, and the telson is a paddle-shaped plate with distal spines.

Abundance:

Over 700 specimens of Yohoia are known from the Walcott Quarry, comprising 1.3% of the specimens counted (Caron and Jackson, 2008) but only few specimens are known from the Raymond and Collins Quarries.

Maximum Size:
23 mm

Ecology:

Life habits: 3D Animation
Feeding strategies: 3D Animation
Ecological Interpretations:

Yohoia is thought to have used its three pairs of cephalic appendages, and possibly the biramous limb on the first body segment, to walk on the sea floor. The animal could also swim by waving the flap-like appendage on the body trunk. The setae on these appendages may have been used for respiration. The pair of frontal appendages were likely used to capture prey or scavenge food particles from the sea floor.

References:

BRIGGS, D. E. G. AND R. A. FORTEY. 1989. The early radiation and relationships of the major arthropod groups. Science, 246: 241-243.

BUDD, G. E. 2002. A palaeontological solution to the arthropod head problem. Nature, 417: 271-275.

CARON, J.-B. AND D. A. JACKSON. 2008. Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology, 258: 222-256.

CHEN, J. Y., D. WALOSZEK AND A. MAAS. 2004. A new ‘great-appendage’ arthropod from the Lower Cambrian of China and homology of chelicerate chelicerae and raptorial antero-ventral appendages. Lethaia, 37: 3-20.

COTTON, T. J. AND S. J. BRADDY. 2004. The phylogeny of arachnomorph arthropods and the origin of the Chelicerata. Transactions of the Royal Society of Edinburgh: Earth Sciences, 94: 169-193.

EDGECOMBE, G. D. 2010. Arthropod phylogeny: An overview from the perspectives of morphology, molecular data and the fossil record. Arthropod Structure and Development, 39: 74-87.

HOU, X. AND J. BERGSTRÖM. 1997. Arthropods of the Lower Cambrian Chengjiang fauna, southwest China. Fossils and Strata, 45: 1-116.

SIMONETTA, A. M. 1970. Studies on non trilobite arthropods of the Burgess Shale (Middle Cambrian). Palaeontographia Italica, 66 (New series 36): 35-45.

WALCOTT, C. D. 1912. Cambrian Geology and Paleontology II. Middle Cambrian Branchiopoda, Malacostraca, Trilobita and Merostomata. Smithsonian Miscellaneous Collections, 57(6): 145-228.

WHITTINGTON, H. B. 1974. Yohoia Walcott and Plenocaris n. gen. arthropods from the Burges

Other Links:

None

Wiwaxia corrugata

3D animation of Wiwaxia corrugata grazing on Morania confluens.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: 3D Animation
Phylum: 3D Animation
Higher Taxonomic assignment: Unranked clade halwaxiids (stem group molluscs)
Species name: Wiwaxia corrugata
Remarks:

The relationship of Wiwaxia is hotly debated; its similarities to the molluscs have been highlighted (Conway Morris, 1985; Scheltema et al., 2003; Caron et al., 2006; Caron et al., 2007), but Matthew’s original view that it was related to the annelid worms (Matthew, 1899) still finds some adherents (Butterfield, 1990; Conway Morris and Peel, 1995; Butterfield, 2006; 2008). It is also possible that Wiwaxia branched off before the molluscs and annelids diverged (Eibye-Jacobsen, 2004). Wiwaxia has recently been placed in a group called the halwaxiids, along with the halkieriids, Orthrozanclus, and Odontogriphus (Conway Morris and Caron, 2007).

Described by: Matthew
Description date: 1899
Etymology:

Wiwaxia – from Wiwaxy Peaks (2,703 m) in Yoho National Park. The word wiwaxy is originally from the Stoney First Nation Nakoda language, meaning “windy.”

corrugata – from the Latin corrugis, “folded, or wrinkled,” in reference to the wrinkled aspect of the sclerites.

Type Specimens: Holotype –ROM8596 in the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none described, although sclerites have been reported from a number of Middle Cambrian deposits extending from northern Canada (Butterfield, 1994) to China (Zhao et al., 1994).

Age & Localities:

Age:
Middle Cambrian, Bathyuriscus-Elrathina Zone (approximately 505 million years ago).
Principal localities:

The Walcott and Raymond Quarries on Fossil Ridge. The Trilobite Beds, Tulip Beds (S7) and Collins Quarry on Mount Stephen. Additional smaller localities are known on Mount Field and Mount Odaray.

History of Research:

Brief history of research:

In an early review of fossils collected from the Trilobite Beds on Mount Stephen by Walker, Canadian palaeontologist G. F. Matthew (1899) described several forms he thought represented tubes of various annelid worms, including one he named Orthotheca corrugata. At the time, Matthew did not know this particular fossil was only part of a much larger organism. It was only when Walcott (1911) discovered articulated and much better preserved specimens from the Phyllopod Bed that the morphology of this species became clearer. Walcott placed corrugata in his new genus Wiwaxia and interpreted it as a polychaete annelid worm (Walcott, 1911). The single best specimen of Walker’s “Orthotheca corrugata” remained unrecognized until it was “rediscovered” in the ROM collections in 1977.

Walcott’s interpretation was called into question in a comprehensive reassessment of the genus (Conway Morris, 1985), and Conway Morris’s link between Wiwaxia mouthparts and the molluscan radula was built upon by Scheltema et al. (2003) and Caron et al. (2006). Butterfield (1990), however, defended an annelid affinity mostly based on the study of individual sclerites, first at the crown-, and later at the stem-group level (Butterfield, 2003; 2006), but further work suggested that the evidence does not conclusively support a close relationship with annelids (Eibye-Jacobsen, 2004). A connection with the halkieriids was drawn early on (Bengtson and Morris, 1984; Conway Morris and Peel, 1995), and expanded more recently (Conway Morris and Caron, 2007).

Other studies have dealt more specifically with the ecology and taphonomy of this animal. The finely spaced patterning of ridges on the scale may have given Wiwaxia an iridescent aspect in life (Parker, 1998). Wiwaxia has proven useful in calculating the extent of decay in fossil assemblages (Caron and Jackson, 2006) and in reconstructing the longer term taphonomic processes responsible for the preservation of the Burgess Shale fossils (Butterfield et al., 2007).

Description:

Morphology:

Wiwaxia corrugata is a slug-like organism up to 5.5 cm in length almost entirely covered (except on the ventral surface) with an array of scale-like elements referred to as sclerites and spines. The body is roughly oval, and lacks evidence of segmentation. The body-covering sclerites are arranged in about 50 rows. In addition, two rows of 7–11 blade-like spines are present on the dorsal surface. Spines and sclerites were inserted directly into the body wall. Wiwaxia’s feeding apparatus consists of two (in rare cases three) toothed plates that have been compared to a molluscan radula or annelid jaws.

Abundance:

Wiwaxia is mostly known from the Walcott Quarry where it is relatively common, representing 0.9% of the specimens counted in the community (Caron and Jackson, 2008).

Maximum Size:
55 mm

Ecology:

Life habits: 3D Animation
Feeding strategies: 3D Animation
Ecological Interpretations:

The similarity of Wiwaxia’s feeding apparatus to that of Odontogriphus suggests that it too fed on the cyanobacterial Morania mats growing on the Cambrian sea floor. Its sclerite armour-plating and long spines, sometimes found broken, suggest that it was targeted by unidentified predators.

References:

BENGSTON, S. AND S. CONWAY MORRIS, 1984. A comparative study of Lower Cambrian Halkieria and Middle Cambrian Wiwaxia. Lethaia, 17:307-329.

BUTTERFIELD, N. J. 1990. A reassessment of the enigmatic Burgess Shale fossil Wiwaxia corrugata (Matthew) and its relationship to the polychaete Canadia spinosa Walcott. Paleobiology: 287-303.

BUTTERFIELD, N. J. 1994. Burgess Shale-type fossils from a Lower Cambrian shallow-shelf sequence in northwestern Canada. Nature, 369(6480): 477-479.

BUTTERFIELD, N. J. 2003. Exceptional fossil preservation and the Cambrian Explosion. Integrative and Comparative Biology, 43:166-177.

BUTTERFIELD, N. J. 2006. Hooking some stem-group “worms”: fossil lophotrochozoans in the Burgess Shale. BioEssays, 28: 1161-1166.

BUTTERFIELD, N. J. 2008. An early Cambrian radula. Journal of Paleontology, 82(3): 543-554.

CARON, J.-B. AND D. A. JACKSON, 2008. Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology, 258: 222-256.

CARON, J.-B., A. H. SCHELTEMA, C. SCHANDER AND D. RUDKIN, 2006. A soft-bodied mollusc with radula from the Middle Cambrian Burgess Shale. Nature, 442(7099): 159-163.

CARON, J.-B., A. H. SCHELTEMA, C. SCHANDER AND D. RUDKIN. 2007. Reply to Butterfield on stem-group “worms:” fossil lophotrochozoans in the Burgess Shale. BioEssays, 29:200-202.

CONWAY MORRIS, S. 1985. The Middle Cambrian metazoan Wiwaxia corrugata (Matthew) from the Burgess Shale and Ogygopsis Shale Shale, British Columbia, Canada. Philosophical Transactions of the Royal Society of London, Series B, 307(1134): 507-582.

CONWAY MORRIS, S. AND J.-B. CARON, 2007. Halwaxiids and the Early Evolution of the Lophotrochozoans. Science, 315(5816): 1255-1258.

CONWAY MORRIS, S. AND J. S. PEEL, 1995. Articulated halkieriids from the Lower Cambrian of North Greenland and their role in early protostome evolution. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 347(1321): 305-358.

EIBYE-JACOBSEN, D. 2004. A reevaluation of Wiwaxia and the polychaetes of the Burgess Shale. Lethaia, 37(3): 317-335.

MATTHEW, G. F. 1899. Studies on Cambrian Faunas, No. 3. Upper Cambrian fauna, Mount Stephen, British Columbia. The trilobites and worms. Transactions of the Royal Society, 5: 39-66.

PARKER, A. R. 1998. Colour in Burgess Shale animals and the effect of light on evolution in the Cambrian. Proceedings of the Royal Society B: Biological Sciences, 265(1400): 967.

SCHELTEMA, A. H., K. KERTH AND A. M. KUZIRIAN, 2003. Original molluscan radula: Comparisons among Aplacophora, Polyplacophora, Gastropoda, and the Cambrian fossil Wiwaxia corrugata. Journal of Morphology, 257(2): 219-245.

WALCOTT, C. D. 1911. Middle Cambrian annelids. Smithsonian Miscellaneous Collections, 57(2): 109-144.

ZHAO, Y.-l., Y. QIAN AND X.-S. LI, 1994. Wiwaxia from Early-Middle Cambrian Kaili Formation in Taijiang, Guizhou. Acta Palaeontologica Sinica, 33:359-366.

Other Links:

http://www.paleobiology.si.edu/burgess/wiwaxia.html

Waputikia ramosa

3D animation of Waputikia ramosa.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: 3D Animation
Phylum: 3D Animation
Higher Taxonomic assignment: Non applicable
Species name: Waputikia ramosa
Remarks:

No revisions of this alga have been published since its original description by Walcott (1919) and its affinities remain uncertain.

Described by: Walcott
Description date: 1919
Etymology:

Waputikia – from the Waputik Icefield, a glacier in Yoho National Park, east of the Burgess Shale.

ramosa – from the Latin ramosus, “full of branches,” in reference to the presence of clumps of branches.

Type Specimens: Syntypes –USNM35409, 35410, 35411 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

Age:
Middle Cambrian, Bathyuriscus-Elrathina Zone (approximately 505 million years ago).
Principal localities:

The Walcott Quarry on Fossil Ridge.

History of Research:

Brief history of research:

This genus was described by Charles Walcott (1919) as a possible red alga. However, like all the algae from the Burgess Shale, it awaits a modern redescription.

Description:

Morphology:

Waputikia has a large central stem with wide branches at irregular intervals. The large branches divide dichotomously (into two), and the smaller tertiary or quaternary branches divide into much finer branches forming small terminal bush-like structures.

Abundance:

Waputikia is very rare and represents only 0.02% of the Walcott Quarry community (Caron and Jackson, 2008).

Maximum Size:
60 mm

Ecology:

Life habits: 3D Animation
Feeding strategies: 3D Animation
Ecological Interpretations:

No attachment structure for this alga has been preserved but it probably lived attached to the sea floor.

References:

CARON, J.-B. AND D. A. JACKSON. 2008. Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology, 258: 222-256.

WALCOTT, C. 1919. Cambrian Geology and Paleontology IV. Middle Cambrian Algae. Smithsonian Miscellaneous Collections, 67(5): 217-260.

Other Links:

None

Wapkia grandis

3D animation of Wapkia elongata and other sponges (Choia ridleyiDiagoniella cyathiformisEiffelia globosaHazelia confertaPirania muricata, and Vauxia bellula) and Chancelloria eros a sponge-like form covered of star-shaped spines.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: 3D Animation
Phylum: 3D Animation
Higher Taxonomic assignment: Demospongia (Order: Monaxonida)
Species name: Wapkia grandis
Remarks:

Wapkia is considered a primitive demosponge (Rigby, 1986). Demosponges, the same group that are harvested as bath sponges, represent the largest class of sponges today.

Described by: Walcott
Description date: 1920
Etymology:

Wapkia – origin of name is unknown

grandis – from the Latin grandis, “large.” This name refers to the large size and complex skeleton of this sponge.

Type Specimens: Lectotype –USNM66458 (W. grandis), in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA. Holotype –ROM53544 (W. elongata), in the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: W. elongata Rigby and Collins, 2004 from the Tulip Beds (S7) on Mount Stephen.

Other deposits: none.

Age & Localities:

Age:
Middle Cambrian, Bathyuriscus-Elrathina Zone (approximately 505 million years ago).
Principal localities:

The Walcott Quarry on Fossil Ridge. The Tulip Beds (S7) on Mount Stephen.

History of Research:

Brief history of research:

Wapkia was described by Walcott in his initial description of the Burgess Shale sponges in 1920. The genus was re-examined by Rigby in 1986. Rigby and Collins (2004) also redescribed the genus and proposed a new species, W. elongata.

Description:

Morphology:

Wapkia is a large elongate or oval sponge with bundles of coarse and fine spicules aligned in long vertical columns and distinct horizontal bundles. The surface of the sponge is smooth and lacks any vertical or horizontal ridges. Spicules are straight and pointed at both ends (oxeas). The exact position of the various bundles of spicules in the skeleton is still uncertain, but it seems that the inner part of the skeleton is reticulate with horizontal wrinkles that are typical of the species and produced by horizontal bundles of spicules. The dermal layer is formed by bundles of oxeas up to 60 mm long which give a characteristic plumose aspect to this sponge. W. elongata is distinguished from W. grandis based on the overall shape of the sponge and different skeletal structures (varying distance between the horizontal spicule bundles).

Abundance:

Wapkia is rare and represents only 0.06% of the Walcott Quarry community (Caron and Jackson, 2008).

Maximum Size:
170 mm

Ecology:

Life habits: 3D Animation
Feeding strategies: 3D Animation
Ecological Interpretations:

Wapkia would have lived attached to the sea floor. Particles of organic matter were extracted from the water as they passed through canals in the sponge’s wall.

References:

CARON, J.-B. AND D. A. JACKSON. 2008. Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology, 258: 222-256.

RIGBY, J. K. 1986. Sponges of the Burgess shale (Middle Cambrian), British Columbia. Palaeontographica Canadiana, 2: 105 p.

RIGBY, J. K. AND D. COLLINS. 2004. Sponges of the Middle Cambrian Burgess Shale and Stephen Formations, British Columbia. Royal Ontario Museum Contributions in Science (1): 155 p.

WALCOTT, C. D. 1920. Middle Cambrian Spongiae. Cambrian Geology and Paleontology IV. Smithsonian Miscellaneous Collections, 67(6): 261-365.

Other Links:

None

Vauxia gracilenta

3D animation of Vauxia bellula and other sponges (Choia ridleyiDiagoniella cyathiformisEiffelia globosaHazelia confertaPirania muricata, and Wapkia elongata) and Chancelloria eros a sponge-like form covered of star-shaped spines.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: 3D Animation
Phylum: 3D Animation
Higher Taxonomic assignment: Demospongea (Order: Verongida)
Species name: Vauxia gracilenta
Remarks:

Vauxia was placed within the hexactinellids by Walcott in his 1920 original description but Rigby (1980) transferred the genus and family to the Demospongea. Demosponges, the same group that are harvested as bath sponges, represent the largest class of sponges today.

Described by: Walcott
Description date: 1920
Etymology:

Vauxia – from Mount Vaux (3,319 m), a mountain Peak in Yoho National Park, British Columbia. The name refers to William Sandys Wright Vaux (1818-1885) an antiquarian at the British Museum.

gracilenta – from the Latin gracilis, “slender,” referring to the delicate structure of the sponge.

Type Specimens: Lectotypes –USNM66515 (V. gracilenta),USNM66508 (V. bellula),USNM66517 (V. densa),USNM66520 (V. venata), in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA. Holotype –ROM53572 (V. irregulara) in the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: V. bellula Walcott, 1920; V. densa Walcott, 1920; V. irregulara Rigby and Collins, 2004; V. venata Walcott, 1920.

Other deposits: none.

Age & Localities:

Age:
Middle Cambrian, Bathyuriscus-Elrathina Zone (approximately 505 million years ago).
Principal localities:

Burgess Shale and vicinity: Vauxia species are known in the Walcott, Raymond and Collins Quarries on Fossil Ridge, the Trilobite Beds, Tulip Beds (S7) and the Collins Quarry on Mount Stephen, and smaller sites on Mount Field and Odaray Mountain. Vauxia is also known from Monarch in Kootenay National Park.

Other deposits: V. bellula Walcott, 1920 from the Middle Cambrian Wheeler and Marjum Formations in Utah (Rigby et al., 2010); V. magna Rigby, 1980 from the Middle Cambrian Spence Shale in Utah (Rigby, 1980).

History of Research:

Brief history of research:

This sponge was originally described by Walcott in 1920. The genus was reviewed by Rigby (1980) and the species redescribed by Rigby (1986) and Rigby and Collins (2004) in their examination of the Burgess Shale sponges.

Description:

Morphology:

Specimens of Vauxia gracilenta can range from simple unbranched forms to more complex branching forms and reach up to 8 cm in height. Each branch is deeply conical and almost cylindrical, with a simple open central cavity (spongocoel) ending in a rounded of flat opening (osculum). The skeleton is double layered with a thin dermal layer and an inner layer (endosomal). The dermal layer has small openings (ostia) and is composed of a dense network of ladder-like fibers supported by radial fibers from the inner layer. The inner layer forms a regular reticulated net-like skeleton of fibers with 4-6 sided polygons which is characteristic of the genus and species. The fibrous elements (spongin) represent tough collagen proteins. There is no evidence of siliceous spicules in the skeleton.

The different species have been identified mostly based on variations of the skeletal elements and the shape of the branches. Some species can reach up to at least 15 cm in height (V. bellulaV. densa).

Abundance:

Vauxia is relatively common in the Raymond Quarry and other sites on Mount Stephen but is rare in the Walcott Quarry where it represents less than 0.05% of the community (Caron and Jackson, 2008).

Maximum Size:
80 mm

Ecology:

Life habits: 3D Animation
Feeding strategies: 3D Animation
Ecological Interpretations:

Vauxia would have lived attached to the sea floor. Particles of organic matter were extracted from the water as they passed through canals in the sponge’s wall.

References:

CARON, J.-B. AND D. A. JACKSON. 2008. Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology, 258: 222-256.

RIGBY, J. K. 1980. The new Middle Cambrian sponge Vauxia magna from the Spence Shale of Northern Utah and taxonomic position of the Vauxiidae. Journal of Paleontology, 54(1): 234-240.

RIGBY, J. K. 1986. Sponges of the Burgess Shale (Middle Cambrian), British Columbia. Palaeontographica Canadiana, 2: 1-105 p.

RIGBY, J. K. AND D. COLLINS. 2004. Sponges of the Middle Cambrian Burgess Shale and Stephen Formations, British Columbia. Royal Ontario Museum Contributions in Science (1): 155 p.

RIGBY, J. K., S. B. CHURCH AND N. K. ANDERSON. 2010. Middle Cambrian Sponges from the Drum Mountains and House Range in Western Utah. Journal of Paleontology, 84: 66-78.

WALCOTT, C. D. 1920. Middle Cambrian Spongiae. Cambrian Geology and Paleontology IV. Smithsonian Miscellaneous Collections, 67(6): 261-365.

Other Links:

None

Sidneyia inexpectans

3D animation of Sidneyia inexpectans.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: 3D Animation
Phylum: 3D Animation
Higher Taxonomic assignment: Unranked clade (stem group arthropods)
Species name: Sidneyia inexpectans
Remarks:

Sidneyia is usually considered to be closely related to the chelicerates, but its exact position relative to this group remains unclear (Budd and Telford, 2009). Sidneyia has been variously placed as the sister group to the chelicerates (Hou and Bergström, 1997), close to the crown on the chelicerate stem lineage (Bruton, 1981; Edgecombe and Ramsköld, 1999; Hendricks and Lieberman, 2008), or basal in the chelicerate stem lineage (Briggs and Fortey, 1989; Wills et al., 1998; Cotton and Braddy, 2004).

Described by: Walcott
Description date: 1911
Etymology:

Sidneyia – after Walcott’s son Sidney, who discovered the first specimen in August of 1910.

inexpectans – from the Latin inexpectans, “unexpected,” since Walcott did not expect to find such a fossil in strata older than the Ordovician.

Type Specimens: Lectotype –USNM57487 (S. inexpectans) in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: A single specimen from the Chengjiang Fauna in China was used to describe a second species, Sidneyia sinica (Zhang et al. 2002), however this was later shown to be incorrectly attributed to Sidneyia (Briggs et al. 2008).

Age & Localities:

Age:
Middle Cambrian, Bathyuriscus-Elrathina Zone (approximately 505 million years ago).
Principal localities:

Burgess Shale and vicinity: The Walcott, Raymond and Collins Quarries on Fossil Ridge, Mount Field and Mount Stephen – Tulip Beds (S7) and other smaller localities – Odaray Mountain and Stanley Glacier.

Other deposits: Sidneyia has been described from the Wheeler Formation (Briggs and Robison, 1984) and the Spence Shale (Briggs et al. 2008) in Utah, and the Kinzers Formation in Pennsylvania (Resser and Howell, 1938).

History of Research:

Brief history of research:

Sidneyia was the first fossil to be described by Walcott (1911) from the Burgess Shale. Further details were added by Walcott the following year (Walcott, 1912), and Strømer (1944) and Simonetta (1963) made minor revisions to Walcott’s reconstruction. A large appendage found in isolation was originally suggested to be the large frontal appendage of Sidneyia (Walcott, 1911), but this was later found to belong to the anomalocaridid Laggania (Whittington and Briggs, 1985). A major study by Bruton (1981) redescribed the species based on the hundreds of available specimens.

Description:

Morphology:

Sidneyia has a short, wide head shield that is convexly domed and roughly square. The two front lateral corners are notched to allow an antenna and a stalked eye to protrude. Other than the pair of antennae, which are long and thin with at least 20 segments, there are no cephalic appendages. The hemispherical and highly reflective eyes are above and posterior to the antennae.

The thorax of Sidneyia has nine wide, thin body segments that widen from the first to the fourth segment and then get progressively narrower posteriorly. The first four thoracic segments bear appendages with a large, spiny basal segment (the coxa) and 8 thinner segments, ending in a sharp claw. The next five thoracic appendages have a similar appendage but also have flap-like filaments in association with the limbs.

The abdomen consists of three circular rings that are much narrower than the thorax, with a terminal, triangular telson. The last segment of the abdomen has a pair of wide flaps that articulate with the telson to form a tail fan. A trace of the straight gut can be seen in some specimens extending from the anterior mouth to the anus on the telson, and pieces of broken trilobites are sometimes preserved in the gut.

Abundance:

Sidneyia is a relatively common arthropod in the Walcott Quarry, comprising 0.3% of the specimens counted (Caron and Jackson, 2008). Hundreds of specimens have been collected from the Walcott Quarry (Bruton, 1981) and in other nearby localities.

Maximum Size:
160 mm

Ecology:

Life habits: 3D Animation
Feeding strategies: 3D Animation
Ecological Interpretations:

Sidneyia walked and swam above the sea floor. Its anterior four thoracic appendages were used for walking, and the spiny basal coxa would crush food items and move them towards the mouth. The posterior five thoracic appendages were used for swimming, with the flap-like filaments undulating through the water column to create propulsion. These filaments were also likely used for breathing, like gills.

The predatory nature of Sidneyia is indicated by its spiny coxa used to masticate food, and the presence of crushed fossil debris in its gut. Sidneyia would have walked or swam above the sea floor, using its eyes and antennae to seek out prey, which it would capture and crush with its anterior appendages.

References:

BRIGGS, D. E. G. AND R. A. FORTEY. 1989. The early radiation and relationships of the major arthropod groups. Science, 246: 241-243.

BRIGGS, D. E. G. AND R. A. ROBISON. 1984. Exceptionally preserved non-trilobite arthropods and Anomalocaris from the Middle Cambrian of Utah. The University of Kansas Paleontological Contributions, 111: 1-24.

BRIGGS, D. E. G., B. S. LIEBERMAN, J. R. HENDRICKS, S. L. HALGEDAHL AND R. D. JARRARD. 2008. Middle Cambrian arthropods from Utah. Journal of Paleontology, 82(2): 238-254.

BRUTON, D. L. 1981. The arthropod Sidneyia inexpectans, Middle Cambrian, Burgess Shale, British Columbia. Philosophical Transactions of the Royal Society of London B, 295: 619-653.

BUDD, G. E. AND M. J. TELFORD. 2009. The origin and evolution of arthropods. Nature, 457(7231): 812-817.

CARON, J.-B. AND D. A. JACKSON. 2008. Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology, 258: 222-256.

CARON, J.-B., R. GAINES, G. MANGANO, M. STRENG, AND A. DALEY. 2010. A new Burgess Shale-type assemblage from the “thin” Stephen Formation of the Southern Canadian Rockies. Geology, 38: 811-814.

COTTON, T. J. AND S. J. BRADDY. 2004. The phylogeny of arachnomorph arthropods and the origin of the Chelicerata. Transactions of the Royal Society of Edinburgh: Earth Sciences, 94: 169-193.

EDGECOMBE, G. D. AND L. RAMSKÖLD. 1999. Relationships of Cambrian Arachnata and the systematic position of Trilobita. Jounral of Paleontology, 73: 263-287.

HENDRICKS , J. R. AND B. S. LIEBERMAN. 2008. Phylogenetic insights into the Cambrian radiation of arachnomorph arthropods. Journal of Paleontology, 82: 585-594.

HOU, X. AND J. BERGSTRÖM. 1997. Arthropods of the Lower Cambrian Chengjiang fauna, southwest China. Fossils and Strata, 45: 1-116.

RASSER, C. E. AND B. F. HOWELL. 1938. Lower Cambrian Olenellus zone of the Appalachians. Bulletin of the Geological Society of America, 49: 195-248.

SIMONETTA, A. M. 1963. Osservazioni sugli artropodi non trilobiti della Burgess Shale (Cambriano medio). II. Contributo: I Generai Sidneyia ed Amiella Walcott 1911. Monitore Zoologico Italiano, 70: 97-108.

STØMER, L. 1944. On the relationships and phylogeny of fossil and recent Arachnomorpha. Norsk Videnskaps-Akademi Skrifter I. Matematisk-Naturvidenskaplig Klasse, 5: 1-158.

WALCOTT, C. D. 1911. Middle Cambrian Merostomata. Cambrian geology and paleontology II. Smithsonian Miscellaneous Collections, 57: 17-40.

WALCOTT, C. D. 1912. Cambrian Geology and Paleontology II. Middle Cambrian Branchiopoda, Malacostraca, Trilobita and Merostomata. Smithsonian Miscellaneous Collections, 57(6): 145-228.

WHITTINGTON, H. B. AND D. E. G. BRIGGS. 1985. The largest Cambrian animal, Anomalocaris, Burgess Shale, British-Columbia. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 309: 569-609.

WILLS, M. A., D. E. G. BRIGGS, R. A. FORTEY, M. WILKINSON AND P. H. A. SNEATH. 1998. An arthropod phylogeny based on fossil and recent taxa, pp. 33-105. In G. D. Edgecombe (ed.), Arthropod fossils and phylogeny. Columbia University Press, New York.

ZHU, X., H. JIAN AND S. DEGAN. 2002. New occurrence of the Burgess Shale arthropod Sidneyia in the Early Cambrian Chengjiang Lagerstätte (South China), and revision of the arthropod Urokodia. Alcheringa: An Australasian Journal of Palaeontology, 26: 1-18.

Other Links:

http://paleobiology.si.edu/burgess/sidneyia.html