''Cadomoceras'' is an extinct

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

genus from the order

Ammonitida Ammonitida, or true ammonites, are an order of Ammonoidea, ammonoid cephalopods that lived from the Jurassic through Paleocene time periods, commonly with intricate ammonitic sutures. Ammonitida is divided into four suborders, the Phylloceratina ...

that lived during the Bajocian Stage of the

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...

, 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, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...

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,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authore ...

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