''Clymenia'' is a genus in the ammonoid order

Clymeniida Clymeniida is an order of ammonoid cephalopods from the Upper Devonian characterized by having an unusual dorsal siphuncle. They measured about in diameter and are restricted to Europe, North Africa, and possibly Australia. Morphologic cha ...

, restricted to the Upper Devonian, characterized as with all clymeniids by a dorsal

siphuncle The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and ...

that runs along the inside of the whorls, unusual for ammonoids. ''Clymenia'' has a closely coiled evolute shell that may be faintly ribbed. The dorsum, on the inside of the whorl, is slightly impressed, a result of the outermost whorl slightly enveloping the previous. The venter may be rounded or acute. The suture is simple, with a broad ventral saddle, broad lateral lobe, a dorso-lateral saddle, and a moderately deep hidden dorsal lobe. Septal necks are usually short and do not form a continuous tube. The suture and siphuncle are characteristic of the family. ''Clymenia'' is type genus of the family Clymeniidae. Is fossils have been found in Europe and Western Australia.

References

;Notes ;Bibliography * ''Rocks, Minerals & Fossils of the World'' by Chris Pellant and Roger Phillips * ''

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''; Geological Society of America and Univ of Kansas Press, 1964 Late Devonian ammonites Ammonites of Australia Ammonite genera Clymeniina {{Clymeniida-stub