Biology:Plectronoceras
Plectronoceras is an extinct genus of early shelled cephalopod, dating to the Late Cambrian.[1][2][3] None of the fossils are complete, and none show the apex or aperture of the shell.[3] Around half of its shell was filled with septa; 7 were recorded in a 2 centimetres (0.79 in) shell.[4] Its shell contains transverse septa separated by about half a millimetre, with a siphuncle on its concave side.[3] It is among the oldest known shelled cephalopods (the Early Cambrian Eoceras being older),[5] and its morphology matches closely that hypothesised for the last common ancestor of all cephalopods.[3]
Plectronoceras is the type genus of the family Plectronoceratidae. Fossils of Plectronoceras have been found in the San Saba Limestone of Texas, United States and in Yunnan, China.[2]
Several species have been included in the genus Plectronoceras, though a 2024 review reorganized their taxonomy; P. exile and P. gracile were synonymyzed with Palaeoceras mutabile, while P. huaibeiense and P. liaotungense were synonymyzed with P. cambria, the type species of Plectronoceras.[6]
References
- ↑ Dzik, J. (1981). "Origin of the cephalopoda". Acta Palaeontologica Polonica 26 (2): 161–191. http://www.paleo.pan.pl/people/Dzik/Publications/Cephalopoda.pdf.
- ↑ 2.0 2.1 Plectronoceras at Fossilworks.org
- ↑ 3.0 3.1 3.2 3.3 Clarke, M.R. (1985), "Main features of cephalopod evolution", in Wilbur, Karl M.; Clarke, M.R.; Trueman, E.R., The Mollusca, 12. Paleontology and neontology of Cephalopods, New York: Academic Press, ISBN 0-12-728702-7
- ↑ Webers, G. F.; Yochelson, E. L. (1989). Crame, J. A.. ed. "Late Cambrian molluscan faunas and the origin of the Cephalopoda". Geological Society, London, Special Publications 47 (1): 29–42. doi:10.1144/GSL.SP.1989.047.01.04. Bibcode: 1989GSLSP..47...29W.
- ↑ Song, Zuchen; Pan, Bing; Guo, Junfeng; Vinther, Jakob; Li, Guoxiang; Han, Jian; Van Iten, Heyo; Zhao, Xiaofang et al. (2026-07-31). "Earliest siphuncle-bearing cephalopod from the early Cambrian" (in en). Nature. doi:10.1038/s41586-026-10868-y. ISSN 0028-0836. PMID 42527604.
- ↑ Pohle, Alexander; Jell, Peter; Klug, Christian (2024-02-29). "Plectronoceratids (Cephalopoda) from the latest Cambrian at Black Mountain, Queensland, reveal complex three-dimensional siphuncle morphology, with major taxonomic implications" (in en). PeerJ 12. doi:10.7717/peerj.17003. ISSN 2167-8359. PMID 38436030. Bibcode: 2024PeerJ..1217003P.
Notable fossil cephalopods (listed by first occurrence) | |||||||||
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| Cenozoic |
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| Mesozoic |
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| Palaeozoic |
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| Cambrian |
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Wikidata ☰ Q7204414 entry
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