Ankyloceras

Ankyloceras is a genus of Early Devonian cephalopods included in the oncocerid family Karoceratidae.

The type species, Ankyloceras nesnayamiense named by Zhuravleva, 1974, comes from Nova Zemlya in Russia.

The shell of Ankyloceras is cyrtoconic, exogastrically curved with a compressed to slightly depressed elliptical cross section more narrowly rounded ventrally than dorsally.

Septal necks in the type species are loxochoanitic, (inwardly slanting to the siphuncle) on marginal side, short recumbent on side facing interior.

Ankyloceras is similar in overall form to the earlier Osbornoceras from North America, except for the details of the siphuncle.