Diademoceras
Diademoceras is a genus of nautiloid cephalopods from the middle Ordovician of North America, named by Rousseau Flower in 1945. The genus is a tainoceratacean included in the nautilid family Rutoceratidae.
| Diademoceras Temporal range: Middle Devonian | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | Nautiloidea |
| Order: | Nautilida |
| Family: | †Rutoceratidae |
| Genus: | †Diademoceras Flower, 1945 |
The shell of Diademoceras is gyroconic, of no more than two whorls, coiled such that whorls do not touch. Whorls are broad, section depressed, sides converge ventrally meeting at a well developed keel. Ornamentation consists of a series of spines on either side as well as transverse striae which form a well developed hyponomic sinus (for the funnel) on the venter. Sutures are straight across the venter, but form a broad shallow lobe on the dorsum. The siphuncle is close to the venter, composed of straight and empty segments, i.e. orthochoanitic.
References
- Bernhard Kummel 1964. Nautiloidea-Nautilida Treatise on Invertebrate Paleontology. Geological Society of America and University of Kansas Press.