Chasmataspidida

Chasmataspidida
Temporal range: Ordovician–Mid Devonian Possible Cambrian record[1]
Fossils of Hoplitaspis hiawathai.
Reconstruction of Dvulikiaspis menneri (middle top), Octoberaspis ushakovi (top left), Hoplitaspis hiawathai (top right), Chasmataspis laurencii (bottom left) and Diploaspis casteri (bottom right).
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Clade: Dekatriata
Order: †Chasmataspidida
Caster & Brooks, 1956
Clades
Synonyms
  • Diploaspidida Simonetta & Delle Cave, 1978

Chasmataspidids, sometime referred to as chasmataspids,[1][2][3] are a group of extinct chelicerate arthropods that form the order Chasmataspidida. Chasmataspidids are probably related to horseshoe crabs (Xiphosura) and/or sea scorpions (Eurypterida),[4][1] with more recent studies suggest that they form a clade (Dekatriata) with Eurypterida and Arachnida.[5][6][7][8] Chasmataspidids are known sporadically in the fossil record through to the mid-Devonian,[9] with possible evidence suggesting that they were also present during the late Cambrian.[1] Chasmataspidids are most easily recognised by having an opisthosoma divided into a wide forepart (preabdomen) and a narrow hind part (postabdomen) each comprising 4 and 9 segments respectively.[1][10] There is some debate about whether they form a natural (i.e. monophyletic) group.[3][1][4]

  1. ^ a b c d e f Cite error: The named reference Chasmataspis2004 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference :0 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference :1 was invoked but never defined (see the help page).
  4. ^ a b Garwood, Russell J.; Dunlop, Jason A. (2014). "Three-dimensional reconstruction and the phylogeny of extinct chelicerate orders". PeerJ. 2: e641. doi:10.7717/peerj.641. PMC 4232842. PMID 25405073.
  5. ^ Lamsdell, James C. (2013-01-01). "Revised systematics of Palaeozoic 'horseshoe crabs' and the myth of monophyletic Xiphosura". Zoological Journal of the Linnean Society. 167 (1): 1–27. doi:10.1111/j.1096-3642.2012.00874.x. ISSN 0024-4082.
  6. ^ Selden, Paul A.; Lamsdell, James C.; Qi, Liu (2015). "An unusual euchelicerate linking horseshoe crabs and eurypterids, from the Lower Devonian (Lochkovian) of Yunnan, China". Zoologica Scripta. 44 (6): 645–652. doi:10.1111/zsc.12124. ISSN 1463-6409. S2CID 55264483.
  7. ^ Lamsdell, James C.; Briggs, Derek E. G.; Liu, Huaibao P.; Witzke, Brian J.; McKay, Robert M. (2015). "A new Ordovician arthropod from the Winneshiek Lagerstätte of Iowa (USA) reveals the ground plan of eurypterids and chasmataspidids". The Science of Nature. 102 (9–10): 63. doi:10.1007/s00114-015-1312-5. ISSN 0028-1042. PMID 26391849. S2CID 8153035.
  8. ^ Lamsdell, James C. (2016). Zhang, Xi-Guang (ed.). "Horseshoe crab phylogeny and independent colonizations of fresh water: ecological invasion as a driver for morphological innovation". Palaeontology. 59 (2): 181–194. doi:10.1111/pala.12220. S2CID 85553811.
  9. ^ Cite error: The named reference :3 was invoked but never defined (see the help page).
  10. ^ Dunlop, Jason A.; Lamsdell, James C. (2017). "Segmentation and tagmosis in Chelicerata". Arthropod Structure & Development. 46 (3): 395–418. doi:10.1016/j.asd.2016.05.002. ISSN 1467-8039. PMID 27240897.