Temporal range: Aptian
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 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 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.
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. tyosiensis
Fossils of Heminautilus have been found in Bulgaria, Colombia (Caballos Formation, Tolima and Une Formation, Boyacá), Egypt, France, Hungary, Japan, Mexico, Spain, Switzerland, Tunesia, the United Kingdom, the United States (Arkansas), Venezuela.
- Badouin, Cyril; Delanoy, Gérard; Moreno Bedmar, Josep Antón; Pictet, Antoine; Vermeulen, Jean; Conte, Gabriel; Gonnet, Roland; Boselli, Patrick; Bonelli, Marc (2016). "Revision of the Early Cretaceous genera Heminautilus SPATH, 1927, and Josanautilus MARTÍNEZ & GRAUGES, 2006 (Nautilida, Cenoceratidae)" (PDF). Carnets Geologicás. 16: 61–212. Retrieved 2017-01-20.
- Kummel, B. (1964). Nautiloidea -Nautilida. Treatise on Invertebrate Paleontology. Geological Society of America and University of Kansas Press.
- 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.
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