Osbornoceras
From Wikipedia, the free encyclopedia
| Osbornoceras Temporal range: | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | Nautiloidea |
| Order: | †Oncocerida |
| Family: | †Karoceratidae |
| Genus: | †Osbornoceras Foeste, 1936 |
Osbornoceras is a genus of Lower Silurian cyrtoconic nautiloid cephalopods known from Ohio and possibly Manitoba, one of five general currently included in the oncocerid family Karoceratidae.
Osbornoceras grew to be somewhat large and is characterized by a narrow, compressed, strongly curved, exograstric shell. The venter, on the outside curvature, is narrowly rounded while the dorsum, on the opposite inside curvature, is more broadly rounded. The body chamber narrows toward the aperture, which has a deep hypomomic sinus.
The siphuncle of Osbornoceras is ventral but not in contact with the ventral wall of the shell. Segments are empty and expanded ventrally but are virtually straight dorsally. Connecting rings are thin, septal necks cyrtochoanitic (outwardly flared).
