''Homoadelphoceras'' is a genus of gyroconic rutoceratid

Nautiloid Nautiloids are a group of marine cephalopods ( Mollusca) which originated in the Late Cambrian and are represented today by the living ''Nautilus'' and ''Allonautilus''. Fossil nautiloids are diverse and speciose, with over 2,500 recorded species ...

from the Middle

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...

of central Europe. Whorls not in contact, venter and dorsum, (outer and inner rims), broadly rounded. Dorso-lateral and ventro-lateral flanks more or less flat, meet at an angle. ''Homoadelphoceras'' resembles ''

Adelphoceras ''Adelphoceras'' is a genus of middle Devonian coiled nautiloids from Europe with an oval whorl section and shallow depressed zone on the inner, dorsal, rim; a strongly contracted T-shaped aperture; ventral siphuncle containing actinosiphonate dep ...

'' which differs in that its whorls are in contact, producing an impressed zone on the inner rim, or dorsum. Both are close to their oncocerid ancestors in that their siphuncles contain laminar actinosiphonate deposits.

References

* Bernard Kummel, 1964. Nautiloidea - Nautilida; Treatise on Invertebrate Paleontology, Part K. Geological Society of America.
Homoadelphceras
in Fossilworks. Prehistoric nautiloid genera {{paleo-nautiloidea-stub