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Tokummia

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Tokummia
Temporal range: Wuliuan
Life restoration
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Order: Hymenocarina
Family: Protocarididae
Genus: Tokummia
Species:
T. katalepsis
Binomial name
Tokummia katalepsis
Cédric Aria, 2017

Tokummia katalepsis is a fossil hymenocarine arthropod from the Burgess Shale as found in a quarry in Marble Canyon in Canada, lived during middle Cambrian (508 million years old).[1] The animal has maxillipeds, mandibles, ring-shaped around 50 body segments, and subdivided basipods. At the front of the animal, there are a pair of antennae, possible eyes and mandibles with pincers. Tokummia shows the oldest record of arthropod pincers. Carapaces had length up to 8.78 cm (3.46 in) long.[1] Its biramous legs had endites (small spikes). It is suggested to be a bottom feeder, being able to walk on the sea floor, and to occasionally swim, and used its pincers to catch prey.[2]

The genus name Tokummia named after Tokumm Creek which runs through the Marble Canyon where it was found. The species name katalepsis means Greek word for "seizing", "gasping" or "holding".[1]

According to research of Tokummia, Hymenocarines like Tokummia, Branchiocaris, Canadaspis and Odaraia are stem group Mandibulata, the group includes millipedes, insects and crustaceans,[1] and this theory is supported in multiple subsequent studies.[3][4][5][6]

References

  1. ^ a b c d Aria, Cédric; Caron, Jean-Bernard (26 April 2017). "Burgess Shale fossils illustrate the origin of the mandibulate body plan". Nature. 545 (7652): 89–92. doi:10.1038/nature22080. PMID 28445464.
  2. ^ "Ouch! U of T paleontologists identify 508-million-year-old sea creature with can opener-like pincers". University of Toronto News.
  3. ^ Aria, Cédric; Caron, Jean-Bernard (2017-12-21). "Mandibulate convergence in an armoured Cambrian stem chelicerate". BMC Evolutionary Biology. 17 (1): 261. doi:10.1186/s12862-017-1088-7. ISSN 1471-2148. PMC 5738823. PMID 29262772.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  4. ^ Zeng, Han; Zhao, Fangchen; Niu, Kecheng; Zhu, Maoyan; Huang, Diying (2020). "An early Cambrian euarthropod with radiodont-like raptorial appendages". Nature. 588 (7836): 101–105. doi:10.1038/s41586-020-2883-7. ISSN 1476-4687.
  5. ^ Aria, Cédric; Zhao, Fangchen; Zhu, Maoyan (2021-03-22). "Fuxianhuiids are mandibulates and share affinities with total-group Myriapoda". Journal of the Geological Society. 178 (5). doi:10.1144/jgs2020-246. ISSN 0016-7649.
  6. ^ Izquierdo‐López, Alejandro; Caron, Jean‐Bernard (2021). Zhang, Xi‐Guang (ed.). "A Burgess Shale mandibulate arthropod with a pygidium: a case of convergent evolution". Papers in Palaeontology. 7 (4): 1877–1894. doi:10.1002/spp2.1366. ISSN 2056-2799.