Heminautilus is an extinct genus of nautiloids from the nautilacean family Cenoceratidae that lived during the Early Cretaceous. ^[1] Fossils of Heminautilus have been registered in rocks of Barremian and Aptian age. ^[2] 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. ^[1]

Species

The following species of Heminautilus have been described: ^[2]

• 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), ^[3] Egypt, ^[4] France, Hungary, ^[5] Japan, Mexico, Spain, Switzerland, Tunisia, ^[6] the United Kingdom, the United States (Arkansas), Venezuela. ^[2]

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.

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