Carinonautilus is a genus of extinct, Middle Cretaceous nautilid with a very involute, compressed shell in which the whorl section is higher than wide, umbilicus is small and shallow, or flanks converge on a narrow venter that has a rounded keel. A furrow on either side marks the ventro-lateral shoulder.

Carinonautilus Temporal range: Aptian–Santonian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	Nautiloidea
Order:	Nautilida
Family:	Nautilidae
Genus:	†CarinonautilusSpengler, 1910 The genus was erected by Spengler in 1910 on the basis of the holotype, found in Middle Cretaceous strata from India. References edit Bernard Kummel, 1964. Nautiloidea -Nautilida.Treatise on Invertebrate Paleontology, Part K. Geological Society of America and University of Kansas Press.