Peytoia

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Peytoia nathorsti
Temporal range: Middle Cambrian
ROM-BurgessShale-LagganiaCambriaFossil.png
Fossil specimen, Royal Ontario Museum
Scientific classification e
Kingdom: Animalia
Stem-group: Arthropoda
Class: Dinocaridida
Order: Radiodonta
Clade: Anomalocarida
Family: Anomalocarididae
Genus: Peytoia
Walcott, 1911
Species: † P. nathorsti
Binomial name
Peytoia nathorsti
Walcott, 1911
Synonyms

Laggania cambria Walcott, 1911

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

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

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 obtain nourishment[1]

108 specimens of Peytoia are known from the Greater Phyllopod bed, where they comprise 0.21% of the community.[2]

History[edit]

The history of Peytoia is somewhat confused and entangled with that of Laggania and Anomalocaris: all three were initially identified as isolated body parts and only later discovered to belong to a single 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 was considerably harder and more easily fossilized than the delicate body.[3]

The first was a detached 'arm', described by Joseph Frederick Whiteaves in 1892 as a crustacean-like creature due to its resemblance to the tail of a lobster or shrimp.[3] The first fossilized mouth was discovered by Charles Doolittle Walcott, who mistook it for a jellyfish and placed it in the genus Peytoia. The body was discovered separately and classified as a sponge in the genus Laggania; the mouth was found with the body, but was interpreted by its discoverer Simon Conway Morris as an unrelated Peytoia that had through happenstance settled and been preserved with the "Laggania". 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 mouth thought to be a jellyfish.[4][3] Whittington linked the two species, but it took several more years for researchers to realize that the continuously juxtaposed Peytoia, Laggania and feeding appendage actually represented a single, enormous creature.[3] According to International Commission on Zoological Nomenclature rules, the oldest name takes priority, which in this case would be Peytoia.[5]

External links[edit]

References[edit]

  1. ^ 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. 
  2. ^ Caron, J. -B.; Jackson, D. A. (October 2006). "Taphonomy of the Greater Phyllopod Bed community, Burgess Shale". PALAIOS 21 (5): 451–465. doi:10.2110/palo.2003.P05-070R.  edit
  3. ^ a b c d 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. 
  4. ^ 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. 
  5. ^ Daley, A. and Bergström, J. (2012). "The oral cone of Anomalocaris is not a classic 'peytoia'." Naturwissenschaften, doi:10.1007/s00114-012-0910-8