Onychodictyon

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Onychodictyon
Temporal range: Cambrian Stage 3
Onychodictyon NGMC.jpg
O. ferox fossil, Geological Museum of China
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
(unranked): Panarthropoda
Phylum: "Lobopodia"
Class: Xenusia
Order: Paronychophora
Family: Onychodictyidae
Genus: Onychodictyon
Hou, Ramsköld, & Bergström, 1991
Type species
Onychodictyon ferox
Hou, Ramsköld, & Bergström, 1991
Species
  • O. ferox
  • O. gracilis
Restoration of Onychodictyon ferox 20210822 Onychodictyon ferox diagrammatic reconstruction.png
Restoration of Onychodictyon ferox

Onychodictyon is a genus of extinct lobopodian known from the Lower Cambrian Chengjiang Maotianshan Shales in the Yunnan Province in China. [1] It was characterized by a stout body covered by fleshy papillae and pairs of sclerotized plates with spines, [2] [1] [3] representing part of the diverse "armoured lobopodians" alongside similar forms such as Microdictyon and Hallucigenia . [1]

The maximum length of Onychodictyon is 70 mm (2.8 in). [1] It has a resemblance to Microdictyon (net-like sclerite ornament) [4] but also Aysheaia and tardigrades (basally-fused terminal leg pairs). [5] Each leg has a pair of curved claws that are thought to have aided Onychodictyon in climbing onto other organisms. [6] By having a unique anterior end structure, Onychodictyon may have been a deposit feeder which means that they would scavenge for organic material from the seafloor. [1] Onychodictyon sclerites appear to have molted with some specimens exhibiting perfectly conjoined plates from successive molts. [7]

Onychodictyon is represented by two species: O. ferox which has a pair of simple eyes and feathery antenniform appendages on its head; [3] and O. gracilis which has a blunt front end without evidence of any appendages. [1]

References

  1. 1 2 3 4 5 6 Liu, Jianni; Shu, Degan; Han, Jian; Zhang, Zhifei; Zhang, Xingliang (2008). "The lobopod "Onychodictyon" from the Lower Cambrian Chengjiang Lagerstätte revisited" (PDF). Acta Palaeontologica Polonica. 53 (2): 285–292. doi: 10.4202/app.2008.0209 .
  2. Ramsköld, L.; Xianguang, Hou (1991). "New early Cambrian animal and onychophoran affinities of enigmatic metazoans" . Nature. 351 (6323): 225–228. doi:10.1038/351225a0. ISSN   1476-4687. S2CID   4309565.
  3. 1 2 Ou, Qiang; Shu, Degan; Mayer, Georg (2012). "Cambrian lobopodians and extant onychophorans provide new insights into early cephalization in Panarthropoda". Nature Communications. 3 (1): 1261. doi:10.1038/ncomms2272. ISSN   2041-1723. PMC   3535342 . PMID   23232391.
  4. Steiner, M.; Hu, S.X.; Liu, J.; Keupp, H. (2012-02-02). "A new species of Hallucigenia from the Cambrian Stage 4 Wulongqing Formation of Yunnan (South China) and the structure of sclerites in lobopodians". Bulletin of Geosciences: 107–124. doi: 10.3140/bull.geosci.1280 . ISSN   1802-8225.
  5. Smith, Martin R.; Ortega-Hernández, Javier (2014). "Hallucigenia's onychophoran-like claws and the case for Tactopoda". Nature. 514 (7522): 363–366. doi:10.1038/nature13576. ISSN   1476-4687. PMID   25132546. S2CID   205239797.
  6. ""Onychodictyon ferox" Lobopodian Fossil from Chengjiang". The Virtual Fossil Museum. The Virtual Fossil Museum. Retrieved 1 December 2019.
  7. Topper, Timothy; Skovsted, Christian; Peel, John; Harper, David (2013). "Molting in the lobopodian "Onychodictyon" from the lower Cambrian of Greenland". Lethaia. 46 (4): 490–495. doi:10.1111/let.12026.