Onychodictyon

Onychodictyon
Temporal range: Cambrian Stage 3
O. ferox fossil, Geological Museum of China
Scientific classification Edit this classification
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

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] 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]

  1. ^ a b c d e 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. ^ a b 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.