Peytoia

Peytoia is a genus of anomalocarids that lived in the Cambrian period, containing two species, Peytoia nathorsti and Peytoia infercambriensis.[1] Its two mouth appendages had long bristle-like spines, it had no fan tail, and its short stalked eyes were behind its mouth appendages.

Peytoia
Temporal range: Cambrian Stage 3–Miaolingian
Fossil specimen, Royal Ontario Museum
Reconstruction
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: †Dinocaridida
Order: †Radiodonta
Family: †Hurdiidae
Genus: †Peytoia
Walcott, 1911
Type species
†Peytoia nathorsti
Walcott, 1911
Species
Synonyms
  • Laggania
    Walcott, 1911
  • Cassubia
    Lendzion, 1977

Paleontologists have determined that these attributes disqualify Peytoia from apex predator status (as opposed to Anomalocaris), to the extent that it used its appendages to filter water and sediment on the sea floor to find food.[2]

108 specimens of Peytoia are known from the Greater Phyllopod bed, where they comprise 0.21% of the community.[3]

Classification

Peytoia belongs to the clade Hurdiidae, and is closely related to the contemporary genus Hurdia.[4]

History
Scale diagram of various Burgess Shale invertebrates, Peytoia nathorsti in purple

The history of Peytoia is entangled with that of "Laggania" and Anomalocaris: all three were initially identified as isolated body parts and only later discovered to belong to one type of animal. This was due in part due to their makeup of a mixture of mineralized and unmineralized body parts; the mouth and feeding appendage were considerably harder and more easily fossilized than the delicate body.[5]

The first was a detached 'arm', described by Joseph Frederick Whiteaves in 1892 as a crustacean-like creature, because it resembled the tail of a lobster or shrimp.[5] The first fossilized mouth was discovered by Charles Doolittle Walcott, who mistook it for a jellyfish and placed it in the genus Peytoia. In the same paper, Walcott described a poorly-preserved body specimen as Laggania; he interpreted it as a holothurian. In 1978, Simon Conway Morris noted that the mouthparts of Laggania were identical to Peytoia, but interpreted this as indicating that Laggania was a composite fossil of Peytoia and the sponge Corralio undulata.[6] Later, while clearing what he thought was an unrelated specimen, Harry B. Whittington removed a layer of covering stone to discover the unequivocally connected arm thought to be a shrimp tail and the mouth thought to be a jellyfish.[7][5] Whittington linked the two species, but it took several more years for researchers to realize that the continuously juxtaposed Peytoia, Laggania and feeding appendage represented one enormous creature.[5] Laggania and Peytoia were named in the same publication, but Simon Conway Morris selected Peytoia as the valid name in 1978, which makes it the valid name according to International Commission on Zoological Nomenclature rules.[6][8]

A second species, Peytoia infercambriensis, was named in 1975 as Pomerania infercambriensis. Its discoverer, Kazimiera Lendzion, interpreted it as a member of Leanchoiliidae.[9] It was subsequently renamed Cassubia infercambriensis because the name Pomerania had already been used for an ammonoid.[10] C. infercambriensis was later recognized as an anomalocarid.[2] It was later determined that the specimen was a composite of a radiodont frontal appendage and the body of an indeterminate arthropod.[1] Due to the close similarity of the appendage to Peytoia nathorsti, C. infercambriensis was reassigned to Peytoia.

References
  1. Daley, A. C.; Legg, D. A. (2015). "A morphological and taxonomic appraisal of the oldest anomalocaridid from the Lower Cambrian of Poland". Geological Magazine. 152 (5): 949–955. doi:10.1017/S0016756815000412.
  2. Dzik, J.; Lendzion, K. (1988). "The Oldest Arthropods of the East European Platform". Lethaia. 21: 29–38. doi:10.1111/j.1502-3931.1988.tb01749.x.
  3. Caron, Jean-Bernard; Jackson, Donald A. (October 2006). "Taphonomy of the Greater Phyllopod Bed community, Burgess Shale". PALAIOS. 21 (5): 451–65. doi:10.2110/palo.2003.P05-070R. JSTOR 20173022.
  4. Vinther, J.; Stein, M.; Longrich, N. R.; Harper, D. A. T. (2014). "A suspension-feeding anomalocarid from the Early Cambrian" (PDF). Nature. 507 (7493): 497–499. doi:10.1038/nature13010. PMID 24670770.
  5. Gould, Stephen Jay (1989). Wonderful life: the Burgess Shale and the nature of history. New York: W.W. Norton. pp. 194–206. ISBN 0-393-02705-8.
  6. Conway Morris, S. (1978). "Laggania cambria Walcott: A composite fossil". Journal of Paleontology. 52 (1): 126–131.
  7. Conway Morris, S. (1998). The crucible of creation: the Burgess Shale and the rise of animals. Oxford [Oxfordshire]: Oxford University Press. pp. 56–9. ISBN 0-19-850256-7.
  8. Daley, A. and Bergström, J. (2012). "The oral cone of Anomalocaris is not a classic 'peytoia'." Naturwissenschaften, doi:10.1007/s00114-012-0910-8
  9. Lendzion, Kazimiera (1975). "Fauna of the Mobergella zone in the Polish Lower Cambrian". 19 (2): 237–242. Cite journal requires |journal= (help)
  10. Lendzion, Kazimiera (1977). "Cassubia - a new generic name for Pomerania Lendzion, 1975". Geological Quarterly. 21 (1).
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