Hexameroceras Temporal range: Late Silurian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	Nautiloidea
Order:	†Oncocerida
Family:	†Hemiphragmoceratidae
Genus:	†Hexameroceras Hyatt, 1884
Species
See text

Hexameroceras is a genus of nautiloid cephalopods belonging to the order Oncocerida that lived during the middle and late Silurian. Its fossils have been found in North America in Indiana, New York, Ohio, and Wisconsin, and in Europe in the Czech Republic.

Hexameroceras is similar to Tetrameroceras but has 3 pairs of dorsolateral sinuses (lateral embayments in the aperture) and narrow mid-dorsal projection or salient. The shell, as for the family, is breviconic, i.e. short, curved toward the apex, straight toward the aperture. The siphuncle is ventral, nummuloidal and contains inwardly radial actinosiphonate deposits.

References[edit]

• Walter C. Sweet, 1964. Nautiloidea - Oncicerida, Treatise on Invertebrate Paleontoloty, Part K. Geological Society of America.
• Hexameroceras in Fossilworks Gateway.