Sirenites
Encyclopedia
Sirenites is an ammonoid cephalopod from the Upper Triassic included in the Ceratitida, and type for the trachyceratid
subfamily Sirenitinae.
Sirenites has a compressed shell with distinct furrow running along the outer rim. Sides of the whorls are flattened to convex and covered with sigmoidal ribs that split on tubercles near the outer shoulder. there are two rows of tubercles on whorl sides and one on the inner, or umbilicle, shoulder. Although Sirenites is a ceratitid ammonoid, it suture is ammonitic.
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....
subfamily Sirenitinae.
Sirenites has a compressed shell with distinct furrow running along the outer rim. Sides of the whorls are flattened to convex and covered with sigmoidal ribs that split on tubercles near the outer shoulder. there are two rows of tubercles on whorl sides and one on the inner, or umbilicle, shoulder. Although Sirenites is a ceratitid ammonoid, it suture is ammonitic.