''Clarkesvillia'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of 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 ...

westonocerids that differs from ''

Faberoceras ''Faberoceras'' is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species. See also * List of prehistoric nautiloid ...

'' in having a more flattened venter and from the later '' Glyptodendron'' in having a more ventrally located

siphuncle The siphuncle is a strand of biological tissue, tissue passing longitudinally through the mollusc shell, shell of a cephalopod mollusc. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the li ...

References

* Teichert, C. 1964. Nautiloidea -Discosorida.

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 Teichert and Moore, eds.
Clarkesvillia-Paleobiology DB
Prehistoric nautiloid genera Discosorida {{paleo-nautiloid-stub