For the plant genus Clymenia, see Clymenia (plant)

Clymenia (plant)

Clymenia is a small genus of flowering plants in the family Rutaceae. The rare Clymenia polyandra, occasionally referred to by the archaic Citrus polyandra, is the lone known member of the genus....

Clymenia is a genus in the ammonoid order Clymeniida

Clymeniida

The Clymeniida constitute a unique order of ammonoid cephalods from the Upper Devonian characterized by having an unusual dorsal siphuncle. They measured about 4 cm in diameter and are restricted to Europe, North Africa, and possibly Australia....

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

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 Spirula...

 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 included in the family Clymeniidae. Is fossils have been found in Europe and Western Australia.