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Morphology of Anomalocaris canadensis from the Burgess Shale

  • Allison C. Daley (a1) (a2) and Gregory D. Edgecombe (a1)

Recent description of the oral cone of Anomalocaris canadensis from the Burgess Shale (Cambrian Series 3, Stage 5) highlighted significant differences from published accounts of this iconic species, and prompts a new evaluation of its morphology as a whole. All known specimens of A. canadensis , including previously unpublished material, were examined with the aim of providing a cohesive morphological description of this stem lineage arthropod. In contrast to previous descriptions, the dorsal surface of the head is shown to be covered by a small, oval carapace in close association with paired stalked eyes, and the ventral surface bears only the triradial oral cone, with no evidence of a hypostome or an anterior sclerite. The frontal appendages reveal new details of the arthrodial membranes and a narrower cross-section in dorsal view than previously reconstructed. The posterior body region reveals a complex suite of digestive, respiratory, and locomotory characters that include a differentiated foregut and hindgut, a midgut with paired glands, gill-like setal blades, and evidence of muscle bundles and struts that presumably supported the swimming movement of the body flaps. The tail fan includes a central blade in addition to the previously described three pairs of lateral blades. Some of these structures have not been identified in other anomalocaridids, making Anomalocaris critical for understanding the functional morphology of the group as a whole and corroborating its arthropod affinities.

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Bengtson, S. 2000. Teasing fossils out of shales with cameras and computers. Palaeontologia Electronica, 3:114.
Bergström, J. 1986. Opabinia and Anomalocaris, Unique Cambrian Arthropods. Lethaia, 19:241246.
Bergström, J. 1987. The Cambrian Opabinia and Anomalocaris . Lethaia, 20:187188.
Briggs, D. E. G. 1979. Anomalocaris, the largest known Cambrian arthropod. Palaeontology, 22:631663.
Briggs, D. E. G. and Mount, J. D. 1982. The occurrence of the giant arthropod Anomalocaris in the Lower Cambrian of Southern California, and the overall distribution of the genus. Journal of Paleontology, 56:1,1121,118.
Briggs, D. E. G. and Nedin, C. 1997. The taphonomy and affinities of the problematic fossil Myoscolex from the lower Cambrian Emu Bay Shale of South Australia. Journal of Paleontology, 71:2232.
Briggs, D. E. G. and Robison, R. A. 1984. Exceptionally preserved nontrilobite arthropods and Anomalocaris from the middle Cambrian of Utah. University of Kansas Paleontological Contributions, 111:123.
Briggs, D. E. G., Erwin, D. H., and Collier, F. J. 1994. The Fossils of the Burgess Shale. Smithsonian Books, Washington, 238 p.
Briggs, D. E. G., Lieberman, B. S., Hendricks, J. R., Halgedahl, S. L., and Jarrard, R. D. 2008. Middle Cambrian arthropods from Utah. Journal of Paleontology, 82:238254.
Budd, G. E. 1998. Arthropod body-plan evolution in the Cambrian with an example from anomalocaridid muscle. Lethaia, 31:197210.
Budd, G. E. 2008. Head structure in upper stem-group euarthropods. Palaeontology, 51:561573.
Butterfield, N. J. 1990. Organic preservation of non-mineralizing organisms and the taphonomy of the Burgess Shale. Paleobiology, 16:272286.
Butterfield, N. J. 2002. Leanchoilia guts and the interpretation of three-dimensional structures in Burgess Shale-type fossils. Paleobiology, 28:155171.
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, 38:811814.
Chen, J., Ramsköld, L., and Zhou, G. Q. 1994. Evidence for monophyly and arthropod affinity of Cambrian giant predators. Science, 264:13041308.
Collins, D. 1996. The “evolution” of Anomalocaris and its classification in the arthropod class Dinocarida (nov) and order Radiodonta (nov). Journal of Paleontology, 70:280293.
Daley, A. C. and Bergström, J. 2012. The oral cone of Anomalocaris is not a classic “peytoia.” Naturwissenschaften, 99:501504.
Daley, A. C. and Budd, G. E. 2010. New anomalocaridid appendages from the Burgess Shale, Canada. Palaeontology, 53:721738.
Daley, A. C., Budd, G. E., Caron, J.-B., Edgecombe, G. D., and Collins, D. 2009. The Burgess Shale anomalocaridid Hurdia and its significance for early euarthropod evolution. Science, 323:1,5971,600.
Daley, A. C., Budd, G. E., and Caron, J.-B. 2013a. The morphology and systematics of the anomalocaridid Hurdia from the middle Cambrian of British Columbia and Utah. Journal of Systematic Palaeontology, 11.
Daley, A. C., Paterson, J. R., Edgecombe, G. D., García-Bellido, D. C., and Jago, J. B. 2013b. New anatomical information on Anomalocaris from the Cambrian Emu Bay Shale of South Australia and a reassessment of it inferred predatory habits. Palaeontology, 56:971990.
Edgecombe, G. D. 2009. Palaeontological and molecular evidence linking arthropods, onychophorans and other Ecdysozoa. Evolution: Education and Outreach, 2:178190.
Fletcher, T. P. and Collins, D. H. 1998. The middle Cambrian Burgess Shale and its relationship to the Stephen Formation in the southern Canadian Rocky Mountains. Canadian Journal of Earth Sciences, 35:413436.
Haug, J. T, Waloszek, D., Maas, A., Liu, Y., and Haug, C. 2012. Functional morphology, ontogeny and evolution of mantis shrimp-like predators in the Cambrian. Palaeontology, 55:369399.
Henriksen, K. L. 1928. Critical notes upon some Cambrian arthropods described by Charles D. Walcott. Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening, 86:120.
Hou, X. and Bergström, J. 2006. Dinocarids—anomalous arthropods or arthropod-like worms, p. 139–158, 847850. In Rong, J., Fang, Z., Zhou, Z., Zhan, R., Wang, X., and Yuan, X. (eds.), Originations, Radiations and Biodiversity Changes–Evidences From The Chinese Fossil Record. Science Press, Beijing.
Hou, X., Bergström, J., and Ahlberg, P. 1995. Anomalocaris and other large animals in the lower Cambrian Chengjiang Fauna of southwest China. GFF, 117:163183.
Legg, D. 2013. Multi-segmented arthropods from the middle Cambrian of British Columbia (Canada). Journal of Paleontology, 87:493501.
Legg, D. A., Sutton, M. D., Edgecombe, G. D., and Caron, J.-B. 2012. Cambrian bivalved arthropod reveals origin of arthrodisation. Proceedings of the Royal Society, Series B (Biological Sciences), 279:46994704.
O'Brien, L. and Caron, J.-B. 2012. A new stalked filter-feeder from the middle Cambrian Burgess Shale, British Columbia, Canada. PLoS ONE, 7:121.
Paterson, J. R., García-Bellido, D. C., Lee, M. S. Y., Brock, G. A., Jago, J. B., and Edgecombe, G. D. 2011. Acute vision in the giant Cambrian predator Anomalocaris and the origin of compound eyes. Nature, 480:237240.
Raymond, P. E. 1935. Leanchoilia and other mid-Cambrian Arthropoda. Bulletin of the Museum of Comparative Zoology, Harvard University, 76:205230.
Resser, C. E. 1929. New lower and middle Cambrian Crustacea. Proceedings of the United States National Museum, 76:118.
Rolfe, W. D. I. 1969. Phyllocarida, p. 269331. In Moore, R. C. (ed.), Treatise on Invertebrate Paleontology, Part R. Geological Society of America and University of Kansas Press.
Rudkin, D. M. 2009. The Mount Stephen Trilobite Beds, p. 91102. In Caron, J.-B. and Rudkin, D. M. (eds.), A Burgess Shale Primer—History, Geology and Research Highlights. The Burgess Shale Consortium, Toronto.
Schönemann, B. and Clarkson, E. N. K. 2012. Functional analysis of lower Cambrian eye system. Palaeontographica A, 297:123149.
Siebold, C. Von, Th. 1848. Lehrbuch det vergleichenden Anatomie der Wirbellosen Thiere. Veit and Comp., Berlin, 679 p.
Simonetta, A. M. and Delle Cave, L. 1975. The Cambrian non trilobite arthropods from the Burgess Shale of British Columbia. A study of their comparative morphology, taxonomy and evolutionary significance. Palaeontographia Italica, 69:137.
Stein, M. 2010. A new arthropod from the early Cambrian of North Greenland, with a ‘great appendage'-like antennula. Zoological Journal of the Linnean Society, 158:477500.
Suzuki, Y. and Bergström, J. 2008. Respiration in trilobites: a reevaluation. GFF, 130:211229.
Vannier, J. 2009. L'explosion cambrienne ou l'émergence des ecosystèmes modernes. Comptes Rendus Palevol, 8:133154.
Vannier, J. and Chen, J. 2005. Early Cambrian food chain: new evidence from fossil aggregates in the Maotianshan Shale Biota, SW China. Palaios, 20:326.
Van Roy, P. and Briggs, D. E. G. 2011. A giant Ordovician anomalocaridid. Nature, 473:510513.
Walcott, C. D. 1908. Mount Stephen rocks and fossils. Canadian Alpine Journal, 1:232248.
Walcott, C. D. 1911. Cambrian geology and paleontology. II. Middle Cambrian holothurians and medusae. Smithsonian Miscellaneous Collections, 57:4168.
Walcott, C. D. 1912. Middle Cambrian Branchiopoda, Malacostraca, Trilobita, and Merostomata. Smithsonian Miscellaneous Collections, 57:145228.
Whiteaves, J. F. 1892. Description of a new genus and species of Phyllocarid Crustacea from the middle Cambrian of Mount Stephen, B.C. Canadian Record of Science, 5:205208.
Whittington, H. B. and Briggs, D. E. G. 1982. A new conundrum from the middle Cambrian Burgess Shale. Proceedings of the Third North American Paleontological Convention, Montreal, 2:573575.
Whittington, H. B. and Briggs, D. E. G. 1985. The largest Cambrian animal, Anomalocaris, Burgess Shale, British Columbia. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 309:569609.
Woodward, H. 1902. The Canadian Rockies—Part 1. On a collection of Middle Cambrian fossils obtained by Edward Whymper, Esq., F.R.G.S., from Mount Stephen, British Columbia. Geological Magazine, 9:502505, 529–544.
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