Temporal range: L Cretaceous
Heminautilus is an extinct nautiloid genus from the nautilacean family Cymatoceratidae that lived during the early Cretaceous (Kummel 1964). 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 (Kummel 1964).
- Kummel,B. 1964. Nautiloidea -Nautilida, in the Treatise on Invertebrate Paleontology, Geological Society of America and University of Kansas Press.
- Sepkoski, J.J. Jr. 2002. A compendium of fossil marine animal genera. D.J. Jablonski & M.L. Foote (eds.). Bulletins of American Paleontology 363: 1–560. Sepkoski's Online Genus Database (CEPHALOPODA)
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