Biology:Plectronoceras
From HandWiki
Short description: Genus of molluscs
| Plectronoceras | |
|---|---|
| |
| Life reconstruction of P. cambria | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | Nautiloidea |
| Order: | †Plectronocerida |
| Family: | †Plectronoceridae |
| Genus: | †Plectronoceras Ulrich & Foerste, 1933 |
| Species | |
| |
Plectronoceras is the earliest known 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] Approximately 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] Its morphology matches closely to 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 .[2]
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). "Late Cambrian molluscan faunas and the origin of the Cephalopoda". in Crame, J. A.. Origins and Evolution of the Antarctic Biota. 47. Geological Society, London: Special Publications. pp. 29. doi:10.1144/GSL.SP.1989.047.01.04.
Notable fossil cephalopods (listed by first occurrence) | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Cenozoic |
| ||||||||
| Mesozoic |
| ||||||||
| Palaeozoic |
| ||||||||
| Cambrian |
| ||||||||
Wikidata ☰ Q7204414 entry
 |  |
