''Aethoceras'' is a genus of

Tarphycerida The Tarphycerida were the first of the coiled cephalopods, found in marine sediments from the Lower Ordovician (middle and upper Canad) to the Middle Devonian. Some, such as ''Aphetoceras'' and ''Estonioceras'', are loosely coiled and gyroconic; ...

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 included in the family

Estonioceratidae The Estonioceratidae are a family of loosely coiled tarphycerids in which the inner side of the whorls, which forms the dorsum, is rounded or flat with no impression, and in which the siphuncle, composed of thick tubular segments, is located ve ...

for which the shell is a loosely coiled, gradually expanding dextral torticone with a slightly depressed whorl section. Siphuncle small, ventral, submarginal. Whorl section somewhat resembles early stages of ''

Estonioceras ''Estonioceras'' is an extinct genus of tarphyceridan nautiloids from the Ordovician of Europe. Sources * ''Dinosaur Encyclopedia'' by Jayne Parsons * ''Fossils'' (Smithsonian Handbooks) by David Ward External links''Estonioceras''in the Pa ...

'' in being laterally fanged. Trochoidal coiling brings to mind the later

Trocholitidae The Trocholitidae are Tarphycerida with whorls in close contact as with the Tarphyceratidae, but in which the siphuncle, similar in structure, becomes dorsal. The Trocholitidae are derived from the Tarphyceratidae, perhaps from different tarphyc ...

. ''Aethoceras'' was originally found in the lower Ordovician of Western Australia.

References

* Furnish & Glennster, 1964, Nautiloidea - Tarphycerida. Treatise on Invertetrate Paleontology, Part C. University of Kansas Press, Lawrence, Ka.
''Aethoceras''
in Fossilworks. 1/5/15 Prehistoric nautiloid genera {{paleo-nautiloidea-stub