Heminautilus

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 Temporal range: Aptian ~125–112 Ma PreꞒ Ꞓ O S D C P T J K Pg N
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 has a discoidal compressed involute shell with flanks converging on a narrow flattened outer margin, the venter. Whorls are higher than 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 (Caballos Formation, Tolima and Une Formation, Boyacá),[3] Egypt,[4] France, Hungary,[5] Japan, Mexico, Spain, Switzerland, Tunesia,[6] the United Kingdom, the United States (Arkansas), Venezuela.[2]

See also

• List of nautiloids

References

1. Kummel, 1964
2. Heminautilus at Fossilworks.org
3. Baudouin et al., 2016, p.87
4. Baudouin, 2016, p.76
5. Baudouin, 2016, p.66
6. Baudouin, 2016, p.72

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: 61–212. doi:10.4267/2042/58977. Retrieved 2017-01-20.
• Kummel, B. (1964). Nautiloidea -Nautilida. Treatise on Invertebrate Paleontology. Geological Society of America and University of Kansas Press.

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. pp. 1–560.