Gomphoceras

Gomphoceras is a questionable nautiloid cephalopod genus assigned to the Oncocerida. The family to which it might belong is undetermined.

Gomphoceras Temporal range: Middle Silurian
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	Nautiloidea
Order:	Oncocerida
Family:	undetermined
Genus:	Gomphoceras Sowerby, 1839

Gomphoceras, named by Sowerby in 1839, is generally short but rapidly expanding, straight to slightly endogastric, with a gibbous body chamber such that all sides are convex. The aperture as vertically transverse, with a hyponomic sinus on a low spout-like process and a larger rounded dorsal sinus connetected above.

Tetrameroceras and Trimeroceras, both oncocerids, are similar in general form, but have more complex apertures.

References

• Sweet (1964). R.C. Moore (ed.). Part K, Mollusca 3. Treatise on Invertebrate Paleontology. Lawrence, Kansas: Geological Society of America and University of Kansas Press. p. K190–K216.