Creatures: Predators



Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Tokummia katalepsis

Artistic reconstruction of Tokummia katalepsis. Danielle Dufault © ROM

Taxonomy:

Kingdom: Predators
Phylum: Predators
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: Predators
Feeding strategies: Predators
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.
Other Links:


Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Titanokorys gainesi

Artistic reconstruction of Titanokorys gainesi – anterior, dorsal, lateral and frontal views. Lars Fields © ROM

Taxonomy:

Kingdom: Predators
Phylum: Predators
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: Predators
Feeding strategies: Predators
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.
Other Links:


Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Surusicaris elegans

Artistic reconstruction of Surusicaris elegans. Marianne Collins © ROM

Taxonomy:

Kingdom: Predators
Phylum: Predators
Higher Taxonomic assignment: Family Isoxyidae?
Species name: Surusicaris elegans
Remarks:

Surusicaris is a close relative of Isoxys, as indicated by the type of carapace, eyes, and frontal pair of raptorial appendages (Aria & Caron, 2015). The presence of spines on the dorsal side of the frontal appendage is a character shared with radiodontans, such as Anomalocaris. Current evidence draws out a consensus among authors placing isoxyids as sister taxa to true arthropods (Edgecombe, 2020; Aria, 2022), although it is not clear whether Surusicaris and Isoxys are part of a single separate lineage (that is, form a monophyletic group).

Described by: Aria and Caron
Description date: 2015
Etymology:

Surusicaris – After Surus, “the Syrian,” which would have been the last elephant of Hannibal, with broad shields covering its sides and missing a tusk.

elegans – Referring to the delicate, laced appearance of the limbs.

Type Specimens: Holotype ROMIP 62977, at 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:

Marble Canyon, Kootenay National Park, British Columbia.

History of Research:

Brief history of research:

Along with Yawunik kootenayi (Aria, Caron & Gaines, 2015), Surusicaris elegans (Aria & Caron, 2015) is one of the first two new arthropods described from the Marble Canyon locality of the Burgess Shale. The original study was based on a single specimen from the original 2012 expedition. No other specimen has been confirmed so far, in the Burgess Shale or elsewhere. Surusicaris has remained a critical taxon in understanding the place of isoxyids in the transition to a euarthropod body plan (Fu et al., 2022; Aria, 2022).

Description:

Morphology:

Surusicaris elegans is about 15mm long and enclosed in a broad carapace made of two semi-circular valves, without spines. Only the posterior extremity of the body and tailpiece remain uncovered. The animal has a well-defined head composed of, at the front, a pair of large spherical eyes and a segmented predatory appendage, and, at the back of the head, under the carapace, three pairs of short limbs with a lobopod aspect. The frontal appendages show a complex ornament of spines on both the ventral and dorsal margins. The trunk limbs are clearly bipartite, forming two separate but similar branches. As for Isoxys, external segmentation of the trunk is not clearly visible. Inside the body, a bold, black trace runs alongside the gut and branches out inside one limb branch, showing similarities to hemolymphatic (“blood”) channels (Aria & Caron, 2015).

Abundance:

A single specimen from the Marble Canyon quarry.

Maximum Size:
About 15 mm.

Ecology:

Life habits: Predators
Feeding strategies: Predators
Ecological Interpretations:

The large lateral eyes and clawed frontal appendages suggest Surusicaris was an active predator, like its close relative Isoxys (Legg & Vannier, 2013). Trunk limbs lack strong functional modifications, but their lobate aspect in addition to their position underneath the carapace indicates that Surusicaris was mostly a swimmer (Aria & Caron, 2015). Although some authors implied a pelagic lifestyle (Vannier & Chen, 2000), isoxyids are commonly found among benthic/nektobenthic assemblages (Caron & Jackson, 2008) and possess general morphological characteristics of other nektobenthic Cambrian arthropods.

References:

  • Aria, C. (2022) The origin and early evolution of arthropods. Biological Reviews 97, 1786–1809.
  • Aria, C. & Caron, J.-B. (2015) Cephalic and limb anatomy of a new isoxyid from the Burgess Shale and the role of ‘stem bivalved arthropods’ in the disparity of the frontalmost appendage. PLoS ONE 10, e0124979.
  • Aria, C., Caron, J.-B. & Gaines, R. (2015) A large new leanchoiliid from the Burgess Shale and the influence of inapplicable states on stem arthropod phylogeny. Palaeontology 58, 629–660.
  • Caron, J.B. & Jackson, D.A. (2008) Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology 258, 222–256.
  • Edgecombe, G.D. (2020) Arthropod origins: Integrating paleontological and molecular evidence. Annual Review of Ecology, Evolution, and Systematics 51, 1–25.
  • Fu, D., Legg, D.A., Daley, A.C., Budd, G.E., Wu, Y. & Zhang, X. (2022) The evolution of biramous appendages revealed by a carapace-bearing Cambrian arthropod. Philosophical Transactions of the Royal Society B: Biological Sciences 377, 20210034.
  • Legg, D.A. & Vannier, J. (2013) The affinities of the cosmopolitan arthropod Isoxys and its implications for the origin of arthropods. Lethaia 46, 540–550.
  • Vannier, J. & Chen, J.Y. (2000) The Early Cambrian colonization of pelagic niches exemplified by Isoxys (Arthropoda). Lethaia 33, 295–311.
Other Links:


Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Misszhouia canadensis

Misszhouia canadensis, holotype, ROMIP 64408

Taxonomy:

Kingdom: Predators
Phylum: Predators
Higher Taxonomic assignment: Subphylum Artiopoda (Hou & Bergström 1997), Class Nektaspida (Raymond 1920), Family Naraoiidae (Walcott 1912).
Species name: Misszhouia canadensis
Remarks:

Artiopoda is the clade including trilobites and their non-biomineralized relatives. The placement of Artiopoda relative to other arthropod groups, and particularly extant lineages, has been the subject of a long and ongoing debate (e.g. Aria et al. 2015; Paterson 2020). Misszhouia is the closest relative of Naraoia, together forming the family Naraoiidae, typified notably by having both cephalon and trunk forming smooth, articulating shields. Naraoiidae could be derived taxa among artiopodans (Mayers et al. 2019), but the internal relationships of Artiopoda have been difficult to resolve and continue to remain at odds between phylogenetic studies (e.g. Lerosey-Aubril et al. 2017; Moysiuk & Caron 2019).

Described by: Mayers, Aria and Caron
Description date: 2018
Etymology:

Misszhouia — in honour of Miss Guiqing Zhou, fossil preparator and technical assistant to Prof. Junyuan Chen from the Nanjing Institute of Geology and Palaeontology, Academia Sinica, China.

canadensis — from being discovered in Canada.

Type Specimens: dsfsdfdsfdsfdasf
Other species:

Holotype ROMIP 64408; paratypes ROMIP 64411, 64438, 64450, 64451, 64509, 64510, 64511, in the Royal Ontario Museum, Toronto, Canada.

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:

Chen and colleagues created the genus Misszhouia mostly based on the distinction that these individuals of “Naraoia” longicaudata did not possess gut ramifications inside the head, compared to Naraoia species from the Chengjiang biota and Burgess Shale. The morphoanatomy and taxonomy of Naraoiidae from China were later thoroughly revised by Zhang and colleagues (2007). Misszhouia canadensis was one of the first taxa found on talus when the Marble Canyon outcrop was discovered in 2012 (Caron et al. 2014). Although these fossils do possess extensive digestive ramifications in the head, morphometric analyses of body shape showed that specimens from both Canada and China formed a genus distinct from Naraoia (Mayers et al. 2019). Morphometric data also allowed for the identification of putative sexual morphs (Zhang et al. 2007; Mayers et al. 2019).

Description:

Morphology:

As an artiopodan, Misszhouia possesses a flattened body divided into a circular cephalon and a trunk, a pair of sensory antennules, and robust walking limbs with masticatory gnathobases, oriented parallel to the ventral surface of the body. Both cephalon and trunk form single smooth shields articulating to one another. In the cephalon, the gut ramifies into extensive diverticula; it is completed by lateral extensions called caeca in the trunk. In addition to the frontal antennules, the head bears another three pairs of limbs. The trunk represents 65% of total body length, with at least 30 limb pairs. The appendages are likely similar to M. longicaudata, with an inner walking branch and an outer, rod-shaped respiratory branch bearing packed lamellae.

Abundance:

Misszhouia is relatively rare at the Marble Canyon Quarry proper, but can be common along Tokumm Creek sites (Mayers et al. 2019).

Maximum Size:
About 8 cm.

Ecology:

Life habits: Predators
Feeding strategies: Predators
Ecological Interpretations:

Misszhouia was construed to be a predator or scavenger based on the presence of long antennules and well-developed gnathobases (masticatory surfaces at the base of the limbs) (Chen et al. 1997). The absence of digestive ramifications in the head of the Burgess Shale species, compared to the one from Chengjiang, suggests either different diets or different frequencies of feeding (Mayers et al. 2019).

References:

  • ARIA, C., CARON, J.-B. and GAINES, R. 2015. A large new leanchoiliid from the Burgess Shale and the influence of inapplicable states on stem arthropod phylogeny. Palaeontology, 58, 629–660.
  • CARON, J.-B., GAINES, R. R., ARIA, C., MANGANO, M. G. and STRENG, M. 2014. A new phyllopod bed-like assemblage from the Burgess Shale of the Canadian Rockies. Nature Communications, 5.
  • CHEN, J. Y., EDGECOMBE, G. D. and RAMSKÖLD, L. 1997. Morphological and ecological disparity in naraoiids (Arthropoda) from the Early Cambrian Chengjiang fauna, China. Records of the Austalian Museum, 49, 1–24.
  • HOU, X. G. and BERGSTRÖM, J. 1997. Arthropods of the Lower Cambrian Chengjiang fauna, southwest China. Fossils and Strata, 45, 1–116.
  • LEROSEY-AUBRIL, R., ZHU, X. and ORTEGA-HERNÁNDEZ, J. 2017. The Vicissicaudata revisited – insights from a new aglaspidid arthropod with caudal appendages from the Furongian of China. Scientific Reports, 7, Article number: 11117.
  • MAYERS, B., ARIA, C. and CARON, J. B. 2019. Three new naraoiid species from the Burgess Shale, with a morphometric and phylogenetic reinvestigation of Naraoiidae. Palaeontology, 62, 19–50.
  • MOYSIUK, J. and CARON, J. B. 2019. Burgess Shale fossils shed light on the agnostid problem. Proc Biol Sci, 286, 20182314.
  • PATERSON, J. R. 2020. The trouble with trilobites: classification, phylogeny and the cryptogenesis problem. Geological Magazine, 157, 35–46.
  • RAYMOND, P. E. 1920. The appendages, anatomy and relationships of trilobites. Memoirs of the Connecticut Academy of Arts and Sciences, 7, 1–169.
  • WALCOTT, C. 1912. Cambrian Geology and Paleontology II. Middle Cambrian Branchiopoda, Malacostraca, Trilobita and Merostomata. Smithsonian Miscellaneous Collections, 57(6), 145–228.
  • ZHANG, X. L., SHU, D. G. and ERWIN, D. H. 2007. Cambrian naraoiids (Arthropoda): morphology, ontogeny, systematics, and evolutionary relationships. Journal of Paleontology, 81, 1–52.
Other Links:


Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Capinatator praetermissus

Artistic reconstruction of Capinatator praetermissus. Marianne Collins © ROM

Taxonomy:

Kingdom: Predators
Phylum: Predators
Higher Taxonomic assignment: None
Species name: Capinatator praetermissus
Remarks:

Capinatator is considered an early chaetognath unrelated to modern forms (Briggs and Caron (2017), see also Vinther and Parry (2019)). Modern chaetognaths have traditionally been difficult to classify based on morphological characters, but thanks to progress in phylogenomic techniques, they are currently viewed as members of the Gnathifera, a clade of very small organisms with complex jaws (Marlétaz et al. 2019).

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

Capinatator — from the Latin “capere,” which means “to grasp,” and the Latin “natator,” which means “swimmer.”

praetermissus — from the Latin “praeter,” which means “besides, beyond”, and “mittere” which means “to send away, to reach out”, referring to the fact that this fossil has long been overlooked.

Type Specimens: Holotype ROMIP 64271_1, at the Royal Ontario Museum, Toronto, Canada
Other species:

Burgess Shale and vicinity: None

Other deposits: None

Age & Localities:

Age:
Middle Cambrian, Wuliuan stage, Burgess Shale Formation (around 505 million years old).
Principal localities:

Mount Stephen (Collins Quarry locality), Walcott Quarry, British Columbia.

History of Research:

Brief history of research:

Two separate species from the Burgess Shale have previously been regarded as chaetognaths, Amiskwia sagittiformis (Walcott 1911) and Oesia disjuncta (Szaniawski 2005). Since then, Amiskwia has been redescribed as a gnathiferan (Caron and Cheung 2019; Vinther and Parry 2019) and Oesia as a hemichordate (Nanglu et al. 2020). Conway Morris (2009) illustrated the first grasping spines of a Burgess Shale chaetognath from a specimen originally discovered by Walcott. Body fossils of Cambrian chaetognaths are extremely rare, with only a few specimens known from China likely representing just one species (Vannier et al. 2007). At the time Capinatator was published, another species was also described from China with a very similar arrangement of spines but with no evidence of the body except for traces of the head (Shu et al. 2017).

Description:

Morphology:

The body is divided into a large head, short neck, an elongate trunk, and a short tail. Lateral and terminal fins did not preserve; these are the first features to decay (Casenove et al. 2011). The head has about 50 simple grasping spines, 25 on each side of the mouth. The spines are claw-shaped and each one may have been reinforced at the tip by a conical structure. A gut trace are visible in some specimens.

Abundance:

49 specimens were initially described, but only 18 preserve evidence of the body.

Maximum Size:
About 9.5 cm.

Ecology:

Life habits: Predators
Feeding strategies: Predators
Ecological Interpretations:

Like modern species, Capinatator likely swam by undulating its body, using its caudal fin for propulsion and lateral fins for added maneuverability. The rarity of specimens preserved with the body suggests that this species did not normally live along the seafloor where it would have been subject to being entrapped by rapid mudflows. Instead, it is likely that Capinatator fed in the water column using its strong grasping spines to capture small swimming prey.

References:

  • BRIGGS, D. E. G. and CARON, J. B. 2017. A large Cambrian chaetognath with supernumerary grasping spines. Current Biology, 27, 2536-2543.e1.
  • CARON, J.-B. and CHEUNG, B. 2019. Amiskwia is a large Cambrian gnathiferan with complex gnathostomulid-like jaws. Communications Biology, 2, 164.
  • CASENOVE, D., OJI, T. and GOTO, T. 2011. Experimental Taphonomy of Benthic Chaetognaths: Implications for the Decay Process of Paleozoic Chaetognath Fossils. Paleontological Research, 15, 146-153, 8.
  • CONWAY MORRIS, S. 2009. The Burgess Shale animal Oesia is not a chaetognath: A reply to Szaniawski (2005). Acta Palaeontologica Polonica, 54, 175-179.
  • MARLÉTAZ, F., PEIJNENBURG, K. T. C. A., GOTO, T., SATOH, N. and ROKHSAR, D. S. 2019. A new spiralian phylogeny places the enigmatic arrow worms among gnathiferans. Current Biology, 29, 312-318.e3.
  • NANGLU, K., CARON, J.-B. and CAMERON, C. B. 2020. Cambrian tentaculate worms and the origin of the hemichordate body plan. Current Biology, 30, 4238-4244.e1.
  • SHU, D., CONWAY MORRIS, S., HAN, J., HOYAL CUTHILL, J. F., ZHANG, Z., CHENG, M. and HUANG, H. 2017. Multi-jawed chaetognaths from the Chengjiang Lagerstätte (Cambrian, Series 2, Stage 3) of Yunnan, China. Palaeontology, 60, 763-772.
  • SZANIAWSKI, H. 2005. Cambrian chaetognaths recognized in Burgess Shale fossils. Acta Palaeontologica Polonica, 50, 1-8.
  • VANNIER, J., STEINER, M., RENVOISÉ, E., HU, S. X. and CASANOVA, J. P. 2007. Early Cambrian origin of modern food webs: evidence from predator arrow worms. Proceedings of the Royal Society B: Biological Sciences, 274, 627-633.
  • VINTHER, J. and PARRY, L. A. 2019. Bilateral jaw elements in Amiskwia sagittiformis bridge the morphological gap between gnathiferans and chaetognaths. Current Biology, 29, 881-888.e1.
  • WALCOTT, C. 1911. Cambrian Geology and Paleontology II. Middle Cambrian annelids. Smithsonian Miscellaneous Collections, 57(5), 109-145.
Other Links:


Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Cambroraster falcatus

Artistic reconstruction of Cambroraster falcatus – anterior, dorsal, lateral and frontal views. Lars Fields © ROM

Taxonomy:

Kingdom: Predators
Phylum: Predators
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:

Cambroraster – Cambro, 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: Predators
Feeding strategies: Predators
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.
Other Links:


Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Yohoia tenuis

3D animation of Yohoia tenuis.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: Predators
Phylum: Predators
Higher Taxonomic assignment: Megacheirans, Clade Cheiromorpha
Species name: Yohoia tenuis
Remarks:

Henriksen (1928) created the family Yohoiidae, and later Simonetta and Delle Cave (1975) erected the order Yohoiida—however, they have so far remained monogeneric (no other included genus other than Yohoia), and are therefore not taxonomically meaningful. Yohoia was originally considered to be a branchiopod crustacean (Walcott, 1912; Simonetta, 1970), but it is now understood as an iconic representative of the class Megacheira. Megacheirans are basal true arthropods with a frontal appendage pointing upward and made of multiple claws (the cheira, or “great appendage”). The relationship of megacheirans with respect to extant lineages is still debated, but cumulative evidence has recently favoured a closer affinity with chelicerates (Aria, 2022).

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, Wuliuan stage, Burgess Shale Formation (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 Yohoia. Another thorough revision was published much later by Haug et al. (2012), who specifically compared the raptorial appendages of Yohoia with chelicerae. Yohoia appears to represent an evolutionary intermediate between early megacheiran taxa called jianfengiids and the relatives of Leanchoilia (Aria et al., 2020).

Description:

Morphology:

The body of Yohoia consists of a head region encapsulated in a cephalic shield and 13 trunk 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, or cheirae, at the front of the head. Each appendage consists of two long segments that bend like an elbow at their articulation, with four long spines at the tip. Three pairs of biramous appendages with walking and increasingly long swimming branches project from beneath the head shield behind the great appendages. The body behind the head consists of ten segments that extend over the back and down the side of the animal, ending in backward-facing triangular points. These trunk segments bear appendages similar to those in the head. The last 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: Predators
Feeding strategies: Predators
Ecological Interpretations:

Like other megacheirans, and a number of modern crustaceans, Yohoia was probably living close to the sea floor and using its raptorial appendages to prey on small animals. Prey items were most likely non-biomineralized, owing to the lack of strong masticatory devices. Breathing could have taken place through the thin, paddle-shaped branches of the appendages, but it is also possible that Yohoia shared dedicated gills with other megacheirans (Liu et al., 2021; Aria et al., 2023).

References:

  • ARIA, C. (2022) The origin and early evolution of arthropods. Biological Reviews 97, 1786–1809.
  • ARIA, C., VANNIER, J., PARK, T.S. & GAINES, R.R. (2023) Interpreting fossilized nervous tissues. BioEssays, 2200167.
  • ARIA, C., ZHAO, F., ZENG, H., GUO, J. & ZHU, M. (2020) Fossils from South China redefine the ancestral euarthropod body plan. BMC Evolutionary Biology 20, 4.
  • HAUG, J.T., WALOSZEK, D., MAAS, A., LIU, Y. & HAUG, C. (2012) Functional morphology, ontogeny and evolution of mantis shrimp-like predators in the Cambrian. Palaeontology 55, 369–399.
  • HENRIKSEN, K.L. (1928) Critical notes upon some Cambrian arthropods described by Charles D. Walcott. Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening: Khobenhavn 86, 1–20.
  • LIU, Y., EDGECOMBE, G.D., SCHMIDT, M., BOND, A.D., MELZER, R.R., ZHAI, D., MAI, H., ZHANG, M. & HOU, X. (2021) Exites in Cambrian arthropods and homology of arthropod limb branches. Nature Communications 12, 4619.
  • SIMONETTA, A.M. (1970) Studies on non trilobite arthropods of the Burgess Shale (Middle Cambrian). Palaeontographia Italica 66 (New series 36), 35–45.
  • SIMONETTA, A.M. & DELLE CAVE, L. (1975) The Cambrian non trilobite arthropods from the Burgess Shale of British Columbia. A study of their comparative morphology taxinomy and evolutionary significance. Palaeontographia Italica 69, 1–37.
  • WALCOTT, C. (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 Burgess Shale, Middle Cambrian, British Columbia. Geological Survey of Canada Bulletin, Department of Energy, Mines and Resources Canada 231, 1–21.
Other Links:

None



Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Stanleycaris hirpex

Stanleycaris hirpex (ROM 59944) – Holotype, part and counterpart. Individual claw. Specimen length = 29 mm. Specimen dry – polarized light. Stanley Glacier.

© ROYAL ONTARIO MUSEUM. PHOTOS: JEAN-BERNARD CARON

Taxonomy:

Kingdom: Predators
Phylum: Predators
Higher Taxonomic assignment: Order Radiodonta, Family Hurdiidae
Species name: Stanleycaris hirpex
Remarks:

With its single pair of jointed frontal appendages, lateral swimming flaps, and a circular mouth structure, Stanleycaris 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 family Hurdiidae. However, other features like the small carapace, short head, and long, streamlined body probably represent ancestral radiodontan traits. Accordingly, Stanleycaris has been recovered as the sister species to all other hurdiid radiodontans in the most recent phylogenetic analysis (Moysiuk and Caron 2022).

Described by: Caron et al.
Description date: 2010
Etymology:

Genus – From Stanley Glacier, 40 kilometres southeast of the Burgess Shale in Kootenay National Park, where the fossils come from and the Latin caris, meaning “shrimp.” The name Stanley was given after Frederick Arthur Stanley (1841-1908), Canada’s sixth Governor General.

species – from the Latin, hirpex, meaning “large rake,” in reference to the rake-like aspect of the appendage.

Type Specimens: Holotype –ROM59944 in the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: none.

Other deposits: Stanleycaris sp. from the mid-Cambrian Wheeler Formation of Utah (Pates et al. 2017).

Age & Localities:

Age:
Middle Cambrian, Wuliuan stage, Burgess Shale Formation (approximately 505 million years ago).
Principal localities:

Stanley Glacier in Kootenay National Park and the Collins Quarry on Fossil Ridge, Yoho National Park. Smaller collections from the Walcott and Raymond Quarries on Fossil Ridge, Tokumm Creek, Mount Odaray, Mount Stephen, and Mount Field.

History of Research:

Brief history of research:

Isolated appendages and oral structures of this species were collected by the Royal Ontario Museum in 1996 from talus slopes at Stanley Glacier, but it was not until 2008, during a larger expedition, that additional specimens were discovered in their proper stratigraphic context. A description of this new genus and species soon followed (Caron et al. 2010). A single isolated appendage from the Wheeler Formation of Utah was described in 2017, representing the only possible occurrence reported outside of the Burgess Shale (Pates et al. 2017). Subsequently, it was noted that the original description of Stanleycaris did not satisfy the requirements of the International Code of Zoological Nomenclature due to its publication in an online-only repository prior to 2012 (Zhuravlev and Gámez Vintaned 2018). The name was ultimately validated by Pates, Daley, and Ortega-Hernández (2018). Moysiuk and Caron later redescribed the original type material, along with new specimens from Stanley Glacier and Tokumm Creek, in detail (2021). Most recently, a large collection of exceptional whole-body remains, mainly from ROM collections on Fossil Ridge in the 1980s and 90s, was recognized as belonging to the species, allowing the first full reconstruction (Moysiuk and Caron 2022). While there had been some debate as to whether radiodontans possessed externally developed body segmentation, the complete Stanleycaris material confirmed this, suggesting that traces of segmentation in other species are merely obscured due to preservation and weathering.

Description:

Morphology:

Stanleycaris has a short head and a relatively long body, the latter composed of 17 well-formed segments plus four filamentous tail blades. A small, oval, domed carapace covers the front of the head. The head bears a pair a pair of stalked compound lateral eyes and a large median eye situated behind the carapace. A pair of frontal appendages project from the head. Each has a series of curving, rake like inner spines, trident-shaped medial spines, and hooked outer spines. The mouth opening, on the underside of the head, is square and surrounded by an array of tooth-bearing plates. Each body segment has a row of gill blades along the underside and a pair of swimming flaps at the sides. The digestive tract includes a long foregut and a segmentally organized midgut. Elements of the nervous system of Stanleycaris are also preserved, including a two-segmented brain, visual processing centers in the eyes, and a pair of ventral nerve cords.

Abundance:

Collectively known from about 300 specimens, the species is most common at the Collins Quarry on Fossil Ridge and Stanley Glacier. It is rare at other localities.

Maximum Size:
About 200 mm.

Ecology:

Life habits: Predators
Feeding strategies: Predators
Ecological Interpretations:

The multitool-like frontal appendages of Stanleycaris could have enabled a variety of feeding functions. They are long and flexible, allowing grappling of prey with the hooked spines at their tips. The rake-like inner spines have been hypothesized to be adapted for sediment sifting, while trident-shaped medial spines would have opposed those on the opposite appendage, together acting like a jaw to tear and crush soft prey. Additional food processing would have been accomplished by the tooth-bearing plates around the mouth (Moysiuk and Caron 2019, 2021). The large compound eyes, particularly in juveniles, show that Stanleycaris was a visual hunter, but the relatively modest number of lenses (estimated at ~1000) suggest it may have been most active in low light conditions (Moysiuk and Caron 2022, 2023). 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). Stanleycaris has the most completely known growth series of any radiodontan, demonstrating that segments were added to the body during early development. Specimens of Stanleycaris showing shriveling of the body and flaps, disarticulation of the appendages and mouthparts, and loss of the top portion of the head have been interpreted as moult remains, providing direct evidence that Stanleycaris moulted periodically as it grew (Moysiuk and Caron 2022, 2023).

References:

  • CARON, J.-B., GAINES, R. R., MÁNGANO, M. G., STRENG, M. and DALEY, A. C. 2010. A new Burgess Shale-type assemblage from the “thin” Stephen Formation of the southern Canadian Rockies. Geology, 38: 811–814.
  • 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.
  • MOYSIUK, J. and CARON, J.-B. 2021. Exceptional multifunctionality in the feeding apparatus of a mid-Cambrian radiodont. Paleobiology, 47: 704–724.
  • MOYSIUK, J. and CARON, J.-B. 2022. A three-eyed radiodont with fossilized neuroanatomy informs the origin of the arthropod head and segmentation. Current Biology, 32: 1–15.
  • MOYSIUK, J. and CARON, J.-B. 2023. A quantitative assessment of ontogeny and moulting in a Cambrian radiodont and the evolution of arthropod development. Paleobiology, 22 pg, IN REVIEW.
  • PATES, S., DALEY, A. C. and ORTEGA-HERNÁNDEZ, J. 2017. Aysheaia prolata from the Utah Wheeler Formation (Drumian, Cambrian) is a frontal appendage of the radiodontan Stanleycaris. Acta Palaeontologica Polonica, 62: 619–625.
  • PATES, S., DALEY, A. C. and ORTEGA-HERNÁNDEZ, J. 2018. Response to Comment on “Aysheaia prolata from the Utah Wheeler Formation (Drumian, Cambrian) is a frontal appendage of the radiodontan Stanleycaris” with the formal description of Stanleycaris. Acta Palaeontologica Polonica, 63: 105–110.
  • 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.
  • ZHURAVLEV, A. and GÁMEZ VINTANED, J. 2018. Comment on “Aysheaia prolata from the Utah Wheeler Formation (Drumian, Cambrian) is a frontal appendage of the radiodontan Stanleycaris” by Stephen Pates, Allison C. Daley, and Javier Ortega-Hernanández. Acta Palaeontologica Polonica, 63: 103–104.
Other Links:

http://geology.geoscienceworld.org/cgi/content/full/38/9/811?ijkey=ZQFY537sTggAw&keytype=ref&siteid=gsgeology



Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Hurdia victoria

3D animation of Hurdia victoria.

Animation by Phlesch Bubble © Royal Ontario Museum

Taxonomy:

Kingdom: Predators
Phylum: Predators
Higher Taxonomic assignment: Radiodonta, Family Hurdiidae
Species name: Hurdia victoria
Remarks:

With its single pair of jointed frontal appendages, lateral swimming flaps, and circular mouth structure, Hurdia possesses all the hallmarks of Radiodonta, part of the stem group to the true arthropods which also includes the iconic Anomalocaris (Collins, 1996). It is the namesake of the radiodontan family Hurdiidae, characterized by frontal appendages with comb or rake-like inner spines (Lerosey-Aubril & Pates, 2018). Hurdia is part of a diverse subgroup of hurdiids with large, elaborate carapaces (Caron & Moysiuk, 2021).

Described by: Walcott
Description date: 1912
Etymology:

Hurdia – from Mount Hurd (2,993 m), a mountain northeast of the now defunct Leanchoil railway station on the Canadian Pacific Railway in Yoho National Park. The peak was named by Tom Wilson for Major M. F. Hurd, a CPR survey engineer who explored the Rocky Mountain passes starting in the 1870s.

victoria – unspecified; perhaps from Mount Victoria (3,464 m) on the border of Yoho and Banff National Parks, named by Norman Collie in 1897 to honour Queen Victoria.

Type Specimens: Lectotypes –USNM57718 (H. victoria) andUSNM57721 (H. triangulata) in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: Hurdia triangulata.

Other deposits: Potentially other species are represented in the Langston and Wheeler Formations of Utah (Lerosey-Aubril et al., 2020; Pates et al., 2018), and possibly the Pioche Formation of Nevada (Pates, Daley, Edgecombe, et al., 2019), the Jince Formation in the Czech Republic (Chlupáč & Kordule, 2002). and the Shuijingtuo Formation in Hubei Province, China (Cui & Huo, 1990).

Age & Localities:

Age:
Middle Cambrian, Wuliuan Stage, Burgess Shale Formation (around 505 million years old).
Principal localities:

The Walcott, Raymond, and Collins Quarries on Fossil Ridge. Also known from other localities on Mount Field, Mount Stephen – Tulip Beds (S7) – and near Stanley Glacier and the Monarch.

History of Research:

Brief history of research:

Although isolated parts of the body of Hurdia were first identified in the early 1900s, no affinity could be determined until the description of whole-body specimens by Daley et al. in 2009. Hurdia victoria was the name originally given to an isolated triangular carapace that Walcott (1912) suggested belonged to an unknown arthropod. Proboscicaris, another isolated carapace, was originally described as a crustacean (Rolfe, 1962). Hurdia’s frontal appendages were first described by Walcott (1911b) as the feeding limbs of Sidneyia, but were later removed from this genus and referred to as “Appendage F” with unknown affinity (Briggs, 1979). Like other radiodontans, the mouthparts were first described as the jellyfish Peytoia nathorsti (Walcott, 1911a). Whittington and Briggs (1985) discovered the first whole body specimens of Peytoia, associating the mouthparts with the former “Appendage F”. When describing Peytoia and Anomalocaris, Whittington and Briggs (1985) also figured a mouth apparatus with extra rows of teeth.

After two decades of collecting at the Burgess Shale, Desmond Collins from the Royal Ontario Museum (ROM) discovered that this extra-spiny mouth part actually belonged to a third type of radiodontan, which also had an “Appendage F” pair and a frontal carapace complex consisting of one Hurdia carapace and two Proboscicaris carapaces (Daley et al., 2009). This is the Hurdia animal. ROM specimens of “Appendage F” showed that it has four distinct morphologies, two of which belong to Hurdia (known from two species, H. victoria and H. triangulata), one to Peytoia nathorsti, and one to an as yet unnamed species (Daley et al., 2013; Daley & Budd, 2010).

Description:

Morphology:

Hurdia has a bilaterally symmetrical body that is broadly divisible into two sections of equal lengths. The anterior region is a complex of non-biomineralized carapaces consisting of one dorsal triangular H-element (previously called Hurdia) and two lateral paddle-shaped P-elements (from Proboscicaris). These carapaces wrap around the anterior margin of the head with the H-element spine protruding forward. The surfaces of the H- and P-elements are covered in a distinctive polygonal pattern similar to that seen on Tuzoia carapaces. A pair of oval eyes on short stalks protrudes upwards through notches in the overlapping posterior corners of the H- and P-elements. Hurdia triangulata differs from Hurdia victoria by having a wider and shorter H-element (Daley et al., 2013). Mouthparts are on the ventral surface of the head, and consist of a circlet of 32 tapering and overlapping plates, 4 large and 28 small, with spines lining the square central opening. Within the central opening are up to five inner rows of toothed plates. A pair of appendages flanks the mouth part, each with nine thin segments with short outer spines and eight elongated ventral spines (Daley et al., 2013; Pates, Daley, & Butterfield, 2019). The posterior half of the body consists of a series of seven to nine segments that extend laterally into triangular flaps. Recently, Van Roy and colleagues (2015) suggested that a second row of flaps might also be present in Hurdia. Each body segment is associated with a band of elongated blades interpreted to be gill structures. The body terminates abruptly in two rounded lobes (Daley et al., 2013). Complete specimens are up to 20 cm in length, although disarticulated fragments suggest a maximum body size up to 30 cm long (Caron & Moysiuk, 2021).

Abundance:

Over 700 specimens of Hurdia have been identified, most of which are disarticulated. Hurdia is found in all Burgess Shale quarries on Fossil Ridge, and is particularly abundant in Raymond Quarry, where it makes up almost 1% of the community (240 specimens). A total of 7 complete body specimens exist.

Maximum Size:
300 mm

Ecology:

Life habits: Predators
Feeding strategies: Predators
Ecological Interpretations:

Hurdia was likely an active swimmer. Like other radiodontans, the animal propelled itself through the water column by undulating its flaps (Usami, 2006) and respiration would have been accomplished through the multiple rows of gills (Daley et al., 2013). The large dorsal carapace, upward facing eyes, and stubby body suggest it spent most of its time near the sea floor and may have fed primarily on burrowing organisms (Moysiuk & Caron, 2019). The function of the frontal carapace remains unknown, although it has been speculated to have played a role in feeding (Caron & Moysiuk, 2021; Daley et al., 2013). Prey items were funneled towards the mouth by a sweeping motion of the of the frontal appendages, with their rake-like inner spines forming a rigid net or cage (de Vivo et al., 2021; Moysiuk & Caron, 2019). Compared to Cambroraster and Titanokorys, the widely spaced spines on Hurdia’s appendages suggest it fed on relatively larger prey items (Caron & Moysiuk, 2021).

References:

  • BRIGGS, D. E. G. (1979). Anomalocaris: The largest known Cambrian arthropod. Palaeontology, 22(3), 631–664.
  • CARON, J.-B., & MOYSIUK, J. (2021). A giant nektobenthic radiodont from the Burgess Shale and the significance of hurdiid carapace diversity. Royal Society Open Science, 8(9), 210664. https://doi.org/10.1098/RSOS.210664
  • CHLUPÁČ, I., & KORDULE, V. (2002). Arthropods of Burgess Shale type from the Middle Cambrian of Bohemia (Czech Republic). Bulletin of the Czech Geological Survey, 77, 167–182.
  • COLLINS, D. (1996). The “evolution” of Anomalocaris and its classification in the arthropod class Dinocarida (nov.) and order Radiodonta (nov.). Journal of Paleontology, 70(2), 280–293. https://doi.org/10.1017/S0022336000023362
  • CUI, Z.-L., & HUO, S.-C. (1990). New discoveries of Lower Cambrian crustacean fossils from western Hubei. Acta Palaeontologica Sinica, 29, 321–330.
  • DALEY, A. C., & BUDD, G. E. (2010). New anomalocaridid appendages from the Burgess Shale, Canada. Palaeontology, 53(4), 721–738. https://doi.org/10.1111/j.1475-4983.2010.00955.x
  • DALEY, A. C., BUDD, G. E., & 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(7), 743–787. https://doi.org/10.1080/14772019.2012.732723
  • DALEY, A. C., BUDD, G. E., CARON, J.-B., EDGECOMBE, G. D., & COLLINS, D. (2009). The Burgess Shale anomalocaridid Hurdia and its significance for early euarthropod evolution. Science, 323(5921), 1597–1600. https://doi.org/10.1126/science.1169514
  • DE VIVO, G., LAUTENSCHLAGER, S., & VINTHER, J. (2021). Three-dimensional modelling, disparity and ecology of the first Cambrian apex predators. Proceedings of the Royal Society B, 288(1955). https://doi.org/10.1098/RSPB.2021.1176
  • LEROSEY-AUBRIL, R., KIMMIG, J., PATES, S., SKABELUND, J., WEUG, A., & ORTEGA-HERNÁNDEZ, J. (2020). New exceptionally preserved panarthropods from the Drumian Wheeler Konservat-Lagerstätte of the House Range of Utah. Papers in Palaeontology, 6(4), 501–531. https://doi.org/10.1002/spp2.1307
  • LEROSEY-AUBRIL, R., & PATES, S. (2018). New suspension-feeding radiodont suggests evolution of microplanktivory in Cambrian macronekton. Nature Communications, 9(1), 3774. https://doi.org/10.1038/s41467-018-06229-7
  • MOYSIUK, J., & 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(1908), 20191079. https://doi.org/10.1098/rspb.2019.1079
  • PATES, S., DALEY, A. C., & BUTTERFIELD, N. J. (2019). First report of paired ventral endites in a hurdiid radiodont. Zoological Letters, 5(1), 18. https://doi.org/10.1186/s40851-019-0132-4
  • PATES, S., DALEY, A. C., EDGECOMBE, G. D., CONG, P., & LIEBERMAN, B. S. (2019). Systematics, preservation and biogeography of radiodonts from the southern Great Basin, USA, during the upper Dyeran (Cambrian Series 2, Stage 4). Papers in Palaeontology, 7(1), 235–262. https://doi.org/10.1002/spp2.1277
  • PATES, S., DALEY, A. C., & LIEBERMAN, B. S. (2018). Hurdiid radiodontans from the middle Cambrian (Series 3) of Utah. Journal of Paleontology, 92(1), 99–113. https://doi.org/10.1017/jpa.2017.11
  • ROLFE, W. D. (1962). Two new arthropod carapaces from the Burgess Shale (Middle Cambrian) of Canada. Breviora Museum of Comparative Zoology, 60, 1–9.
  • 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.
  • VAN ROY, P., DALEY, A. C., & BRIGGS, D. E. G. (2015). Anomalocaridid trunk limb homology revealed by a giant filter-feeder with paired flaps. Nature, 522(7554), 77. https://doi.org/10.1038/nature14256
  • WALCOTT, C. D. (1911a). Middle Cambrian holothurian and medusae. Smithsonian Miscellaneous Collections, 57, 41–68.
  • WALCOTT, C. D. (1911b). Middle Cambrian Merostomata. Cambrian Geology and Paleontology II. Smithsonian Miscellaneous Collections, 57, 17–40.
  • WALCOTT, C. D. (1912). Middle Cambrian Branchiopoda, Malacostraca, Trilobita and Merostomata. Smithsonian Miscellaneous Collections, 57, 145–228.
  • WHITTINGTON, H. B., & BRIGGS, D. E. G. (1985). The largest Cambrian animal, Anomalocaris, Burgess Shale, British Columbia. Philosophical Transactions of the Royal Society B: Biological Sciences, 309(1141), 569–609. https://doi.org/10.1098/rstb.1985.0096
Other Links:

http://www.sciencemag.org/content/323/5921/1597.abstract



Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Liangshanella burgessensis

3D animation of Liangshanella burgessensis.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: Predators
Phylum: Predators
Higher Taxonomic assignment: Hymenocarines?, Order Bradoriida (Raymond 1935).
Species name: Liangshanella burgessensis
Remarks:

Liangshanella is a bradoriid belonging to the family Svealutidae (Siveter & Williams 1997). The bradoriids were traditionally compared to other bivalved arthropods within or close to crustaceans, such as Recent ostracods (e.g. Sylvester-Bradley, 1961) and Cambrian phosphatocopids (e.g. Maas et al. (2003)). More recently, authors have argued bradoriids to represent more basal members of the arthropod stem group (e.g. Hou et al. (1996); Shu et al. (1999); Hou et al. (2010)). A recent reexamination of appendage morphology in the bradoriid Kunmingella supports a placement of these arthropods outside of crown groups (Zhai et al. 2019), but their exact phylogenetic placement remains unclear.

Described by: Siveter and Williams
Description date: 1997
Etymology:

Liangshanella – from Liangshan, a region in South Shaanxi, China.

burgessensis – from the Burgess Shale. The name is derived from Mount Burgess (2,599 m), a mountain peak in Yoho National Park. Mount Burgess was named in 1886 by Otto Klotz, the Dominion topographical surveyor, after Alexander Burgess, a former Deputy Minister of the Department of the Interior.

Type Specimens: Holotype –USNM272083 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: L. circumbolina from the Flinders Ranges in South Australia; L. liangshanensis, L. rotundata, L. orbicularis, L. yunnanensis and L. baensis from southern China; L. lubrica from the Tongying Formation in Hubei, China; L. sayutinae from the Trans-Baikal area in the Russian Far-East and Greenland; L. birkenmajeri from Antarctica. See references in Siveter and Williams (1997).

Age & Localities:

Age:
Middle Cambrian, Wuliuan stage, Burgess Shale Formation (approximately 505 million years ago).
Principal localities:

The Walcott and Raymond Quarries on Fossil Ridge.

History of Research:

Brief history of research:

Liangshanella liangshanensis is the type species of this genus and was first described by Huo (1956) from Lower Cambrian rocks of south China. urther species have since been described in China (Zhang, 1974; Li, 1975; Qian and Zhang, 1983; Zhang, 2007), Russia and Greenland (Melnikova, 1988), Australia (Topper et al., in press) and Antarctica (Wrona, 2009). Liangshanella burgessensis from the Burgess Shale was described by Siveter and Williams (1997), and the genus has been included in studies on the biogeography, evolution and affinity of the bradoriids (e.g. Shu and Chen, 1994; Williams et al., 2007). The most recent insight on the morphoanatomy of these arthropods comes from computed tomographic imagery of Kunmingella species from the Chengjiang biota (Zhai et al. 2019), which confirms both the presence of biramous enditic appendages and the lack of clear crown-group synapomorphies.

Description:

Morphology:

Like all bradoriids, Liangshanella burgessensis has a small bivalved carapace with a straight dorsal hinge held together by a band of cuticle. The carapaces range in length from 0.66 mm – 4.25 mm and were soft and unmineralized. The bivalved carapace of L. burgessensis is sub-circular, with the anterior end being slightly narrower than the posterior end. There is a marginal ridge along the lateral surface of the valves. A centrally situated, sub-circular muscle scar composed of numerous small pits can be seen inside the valve. Based on appendicular evidence from other bradoriid taxa, L. burgessensis would have possessed short, spinose antennules, very reduced eyes—if at all present—, and biramous post-frontal appendages characterized by the presence of well-developed “fingers” on the inner side, called endites.

Abundance:

Liangshanella burgessensis is known from thousands of specimens and is the most common taxon in the Walcott Quarry (11.8% of the community, Caron and Jackson, 2008).

Maximum Size:
10 mm

Ecology:

Life habits: Predators
Feeding strategies: Predators
Ecological Interpretations:

Williams et al. (2007) considered bradoriids to be most likely epibenthic dwellers feeding on organic detritus or small non-biomineralized prey items; an ecology comparable to that of ostracods. These authors also pointed out that the large disparity of carapace shapes probably reflected a variety of different sub-niches and lifestyles. Their size and abundance would have made them in turn a common food source for larger animals, as indicated by coprolite composition (Vannier & Chen 2005).

References:

  • CARON, J. B. and JACKSON, D. A. 2008. Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology, 258, 222–256.
  • HOU, X., WILLIAMS, M., SIVETER, D. J., SIVETER, D. J., ALDRIDGE, R. J. and SANSOM, R. S. 2010. Soft-part anatomy of the Early Cambrian bivalved arthropods Kunyangella and Kunmingella : significance for the phylogenetic relationships of Bradoriida. Proceedings of the Royal Society B: Biological Sciences, 277, 1835–1841.
  • HOU, X., SIVETER, D. J., WILLIAMS, M., WALOSSEK, D., BERGSTRÖM, J., SMITH, M. P. and THOMAS, A. T. 1996. Appendages of the arthropod Kunmingella from the Early Cambrian of China; its bearing on the systematic position of the Bradoriida and the fossil record of the Ostracoda. Palaeontology Newsletter, 32.
  • HUO, S. 1956. Brief notes on lower Cambrian Archaeostraca from Shensi and Yunnan. Acta Palaeontologica Sinica, 4, 1131–1145.
  • LI, Y. 1975. On the Cambrian ostracods with new material from Sichuan, Yunnan and Shaanxi, China. Professional Papers on Stratigraphy & Palaeontology, 2, 37–72.
  • MAAS, A., WALOSZEK, D. and MÜLLER, K. J. 2003. Morphology, ontogeny and phylogeny of the Phosphatocopina (Crustacea) from the Upper Cambrian ‘Orsten’ of Sweden. Fossil and Strata. Vol. 49. Taylor & Francis, Oslo.
  • MELNIKOVA, L. M. 1988. Nekotoryye bradoriidy (Crustacea) iz botomskogo yarusa vostochnogo Zabaykal’ya. Paleontologicheskiy Zhurnal, 1, 114–117.
  • MILLER, S. A. 1889. North American geology and palaeontology for the use of amateurs, students and scientists. Western Methodist Book Concern, Cincinnati.
  • QIAN, Y. and ZHANG, S. 1983. Small shelly fossils from the Xihaoping Member of the Tongying Formation in Fangxian County of Hubei Province and their stratigraphical significance. Acta Palaeontologica Sinica, 22, 82–94.
  • SHU, D. and CHEN, L. 1994. Cambrian palaeobiogeography of Bradoriida. Journal of Southeast Asian Earth Sciences, 9, 289–299.
  • SHU, D. G., VANNIER, J., LUO, H. L., CHEN, L., ZHANG, X. L. and HU, S. X. 1999. Anatomy and lifestyle of Kunmingella (Arthropoda, Bradoriida) from the Chengjiang fossil Lagerstätte (lower Cambrian; Southwest China). Lethaia, 32, 279–298.
  • SIVETER, D. J. and WILLIAMS, M. 1997. Cambrian bradoriid and phosphatocopid arthropods of North America. Special Papers in Palaeontology, 57, 67.
  • TOPPER, T. P., SKOVSTED, C. E., BROCK, G. A. and PATERSON, J. R. 2007. New bradoriids from the lower Cambrian Mernmerna Formation, South Australia: systematics, biostratigraphy and biogeography. Memoirs of the Association of Australasian Palaeontologists, 33, 67–100.
  • VANNIER, J. and CHEN, J. 2005. Early Cambrian food chain: New evidence from fossil aggregates in the Maotianshan Shale biota, SW China. PALAIOS, 20, 3–26.
  • WILLIAMS, M., SIVETER, D. J., POPOV, L. E. and VANNIER, J. M. C. 2007. Biogeography and affinities of the bradoriid arthropods: Cosmopolitan microbenthos of the Cambrian seas. Palaeogeography, Palaeoclimatology, Palaeoecology, 248, 202–232.
  • WRONA, R. 2009. Early Cambrian bradoriide and phosphatocopide arthropods from King George Island, West Antarctica: Biogeographic implications. Polish Polar Research, 30, 347–377.
  • ZHAI, D., WILLIAMS, M., SIVETER, D. J., HARVEY, T. H. P., SANSOM, R. S., GABBOTT, S. E., SIVETER, D. J., MA, X., ZHOU, R., LIU, Y. and HOU, X. 2019. Variation in appendages in early Cambrian bradoriids reveals a wide range of body plans in stem-euarthropods. Communications Biology, 2, 329.
  • ZHANG, W. 1974. Bradoriida. In Handbook of Stratigraphy and Palaeontology of Southwest China, Science Press, Beijing, 107–111 pp.
  • ZHANG, X.-G. 2007. Phosphatized Bradoriids (Arthropoda) from the Cambrian of China. Palaeontographica Abteilung A, 281, 93–173.
Other Links:

None