''Adelphoceras'' is a genus of middle Devonian coiled

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 speci ...

s 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 deposits, and two rows of spines on either side. ''Adelphoceras'' is included in the nautilid family

Rutoceratidae Rutoceratidae is a family of prototypical nautilids, derived probably from either Brevicoceratidae or Acleistoceratidae of the order Oncocerida early in the Devonian. Rutoceratidae comprise a family within the oncocerid superfamily Tainocerata ...

, and is also a part of the

Tainoceratoidea The Tainoceratoidea are a superfamily in the cephalopod order Nautilida characterized by straight to loosely coiled shells, generally to a degree such that the width is greater than the height, to quadrate whorl section. Many bore spines, ribs, f ...

References

* Bernhard Kummel, 1964. Nautiloidea - Nautilida. Treatise on Invertebrate Paleontology, Part K. Geological Society of America and University of Kansas Press. Prehistoric nautiloid genera Fossil taxa described in 1870 {{paleo-nautiloidea-stub