Plagiostomoceras
Encyclopedia
Plagiostomoceras is an orthocerid
cephalopod from the lower Paleozoic
(Upper Ordovician to Lower Devonian) of Europe and Australia.
Shells of Plagiostomoceras are long slender orthocones with circular to slightly depressed cross sections. Sutures are straight or slightly oblique and may have faint lateral lobes. The siphuncle
is central or offset, probably ventrally. The aperture is strongly oblique, sloping adapically toward the presumed venter.
Plagiostomoceras is included in the Michelinoceratinae, a subfamily of the Orthoceratidae
.
Orthocerida
Orthocerida is an order of extinct nautiloid cephalopods also known as the Michelinocerda that lived from the Early Ordovician possibly to the Late Triassic . A fossil found in the Caucasus suggests they may even have survived until the Early Cretaceous...
cephalopod from the lower Paleozoic
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
(Upper Ordovician to Lower Devonian) of Europe and Australia.
Shells of Plagiostomoceras are long slender orthocones with circular to slightly depressed cross sections. Sutures are straight or slightly oblique and may have faint lateral lobes. The siphuncle
Siphuncle
The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and Spirula...
is central or offset, probably ventrally. The aperture is strongly oblique, sloping adapically toward the presumed venter.
Plagiostomoceras is included in the Michelinoceratinae, a subfamily of the Orthoceratidae
Orthoceratidae
Orthoceratidae, is an extinct family of actively mobile carnivorous cephalapods, subclass Nautiloidea, that lived in what would be North America, Europe, Asia, Africa, and Australia from the Ordovician through Triassic from 490—203.7 mya, existing for approximately .-Taxonomy:Orthoceratidae was...
.
References
- Sweet, W.C. 1964. Nautiloidea-Orthocerida. Treatise on Invertebrate PaleontologyTreatise on Invertebrate PaleontologyThe Treatise on Invertebrate Paleontology published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and covering every phylum, class, order, family, and genus of fossil and...
, Part K. Geological Society of America and University of Kansas press. Teichert & Moore,(eds)