''Cadomoceras'' is an extinct

cephalopod A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...

genus from the order

Ammonitida Ammonitida is an order of ammonoid cephalopods that lived from the Jurassic through Paleocene time periods, commonly with intricate ammonitic sutures. Ammonitida is divided into four suborders, the Phylloceratina, Lytoceratina, Ancyloceratina, a ...

that lived during the Bajocian Stage of the

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...

, approximately 178 to 175 million years ago. ''Cadamoceras'' has smooth inner whorls but the outer has course plications on the outer (ventral) flanks and across the venter. The

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...

has a large scoop-like rostrum and spatulate lappets flanking either side. The suture is straight with small, widely separated lobes. ''Cadamoceras'', named by Munier-Chalmas in 1892, is a member of the ammonitid family Haploceratidae which is part of the superfamily Haplocerataceae.

References

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and co ...

, Part L, Ammonoidea (L273) Geological Society of America and Univ of Kansas Press, 5th printing 1990. Jurassic ammonites Bajocian life Haploceratoidea {{ammonite-stub