Anasirenites is an extinct ammonoid cephalopod genus within the family Trachyceratidae

Trachyceratidae

The Trachyceratidae is a family of ceratitid ammonoid cephalopods that lived during the Middle- and Late Triassic characterized by shells that are more or less involute and highly ornamented....

 which is part of the ceratitid

Ceratitida

The Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as well as ancestral forms from the Upper Permian, the exception being the phylloceratids which gave rise to the great diversity of post Triassic ammonites....

 superfamily Clydonitaceae

Clydonitaceae

The Clydonitaceae is a superfamily in the ammonoid cephalopod order Ceratitida characterized by generally costate and turberculate shells with smooth, grooved, or keeled venters and sutures that are commonly ceratitic or ammonitic but goniatic in a few offshoots.-Taxonomy:The Clydonitaceae unites...

; sometimes considered a subgenus of Sirenites

Sirenites

Sirenites is an ammonoid cephalopod from the Upper Triassic included in the Ceratitida, and type for the trachyceratid subfamily Sirenitinae....

. Anasirenites is characterized by a ventral furrow bordered on either side by a continuous keel. The shell, as for Sirenites, is compressed with whorls flattened-convex on the sides. Sigmoidal ribs on the flanks bifurcate near the ventro-lateral shoulder on tubercles and project sharply adorally. Whorl sides are tuberculate with tubercles arranged in spiral lines. The suture is ammonitic. Anasirenites, first described by Mojsisovics in 1893 is known from the Upper Triassic of the Alps, Sicily , and the Himalaya.

References

• Treatise on Invertebrate Paleontology, part L, Ammonoidea; Geological Society of America and the University of Kansas Press. (L-158-159,& rel)