Heminautilus

Heminautilus Temporal range: Aptian ~
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	Nautiloidea
Order:	Nautilida
Superfamily:	Nautilaceae
Family:	Cenoceratidae
Genus:	Heminautilus Spath 1927
Species
H. boselliorum H. etheringtoni H. japonicus H. lallierianus H. rangei H. sanctaecrucis H. saxbii H. stantoni H. tejeriensis H. tyosiensis H. verneuilli

Heminautilus is an extinct genus of nautiloids from the nautilacean family Cenoceratidae that lived during the Early Cretaceous. Fossils of Heminautilus have been registered in rocks of Barremian and Aptian age. Nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.

Heminautilus has a discoidal compressed involute shell with flanks converging on a narrow flattened outer margin, the venter. Whorls are higher than they are wide. The suture is sinuous with a ventral lobe, subtriangular saddles on the ventral shoulders, broad lateral lobes, and narrow rounded saddles on the umbilical shoulders. The siphuncle is subcentral.

Species

The following species of Heminautilus have been described:

• H. boselliorum
• H. etheringtoni
• H. japonicus
• H. lallierianus
• H. rangei
• H. sanctaecrucis
• H. saxbii
• H. stantoni
• H. tejeriensis
• H. tyosiensis
• H. verneuilli

Distribution

Fossils of Heminautilus have been found in Bulgaria, Colombia (at Caballos Formation, Boyacá, Tolima and Une Formation), Egypt, France, Hungary, Japan, Mexico, Spain, Switzerland, Tunisia, the United Kingdom, the United States (Arkansas), Venezuela.

See also

• List of nautiloids

References

Bibliography

• Baudouin, Cyril; Delanoy, Gérard; Moreno Bedmar, Josep Antón; Pictet, Antoine; Vermeulen, Jean; Conte, Gabriel; Gonnet, Roland; Boselli, Patrick; Boselli, Marc (2016). "Revision of the Early Cretaceous genera Heminautilus SPATH, 1927, and Josanautilus MARTÍNEZ & GRAUGES, 2006 (Nautilida, Cenoceratidae)" (PDF). Carnets de Géologie. 16 (5): 61–212. doi:10.4267/2042/58977. Retrieved 2017-01-20.
• Kummel, B. (1964). Nautiloidea -Nautilida. Geological Society of America and University of Kansas Press. {{cite book}}: |work= ignored (help)

Further reading

• Sepkoski Jr., J.J. (2002). D.J. Jablonski & M.L. Foote (ed.). "A compendium of fossil marine animal genera". Bulletins of American Paleontology. 363: 1–560.