''Augustoceras'' is a genus of

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

cephalopod A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...

s included in the order

Oncocerida The Oncocerida comprise a diverse group of generally small nautiloid cephalopods known from the Middle Ordovician to the Mississippian (early Carboniferous; one possible member is known from the Early Permian), in which the connecting rings are t ...

and family

Valcouroceratidae The Valcouroceratidae is a family within the Oncocerida, nautiloid cephalopods from the middle and upper Ordovician, established by Rousseau Flower in 1945. Diagnosis Valcouroceratids are characterized by exogastric cyrtocones and brevicones t ...

. It is known from the Middle and Upper

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

of Kentucky and Ohio in the United States. Shells of ''Augustocers'' are slender, upwardly curved, fusiform, exogastric cyrtocones with subtriangular cross-sections, short chambers, oblique sutures, and subventral siphuncles with simple internal radial actinosiphonate deposits. '' Kindleoceras'' from the

Upper Ordovician The Late Ordovician is the third and final epoch of the Ordovician period, lasting million years and spanning from around 458.2 to 443.1 million years ago. The rocks associated with this epoch are referred to as the Upper Ordovician Series. At ...

of Ontario differs in having a more triangular cross-section and more numerous actinosiphonate rays in its siphuncle.

References

*Walter C Sweet, 1964 Nautiloidea-Oncocerida.

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authore ...

Part K Mollusca 3. Geological Society of America and University of Kansas Press Oncocerida Prehistoric nautiloid genera Middle Ordovician first appearances Late Ordovician extinctions Fossils of Georgia (U.S. state) {{paleo-nautiloidea-stub