genus D

New genus D Korn & Hairapetian (in press) Type species New species O to be described by Korn & Hairapetian (in press); original designation. Diagnosis Genus of the family Tainoceratidae with subinvolute or subevolute conch; whorl profile depressed and polygonal with a shallow or broad midventral longitudinal groove. Umbilical margin pronounced and narrowly rounded, flanks convergent. Sculpture with one row of nodes on the ventrolateral shoulder. Suture line strongly depending on the shape of the whorl profile, with rounded V-shaped external lobe and broadly rounded lateral lobe (from Korn & Hairapetian in press). Included species Transcaucasia (Abich 1878): Nautilus dorso plicatus Abich, 1878, Wuchiapingian, Azerbaijan. Central Iran (Korn & Hairapetian in press): new species O to be described by Korn & Hairapetian (in press), Wuchiapingian. Remarks According to Korn & Hairapetian (in press), the new genus D is a genus with a morphology that is similar to that of some species of Tainoceras, but with a much less developed sculpture. In contrast to Tainoceras, which usually has two rows of nodes or tubercles in the ventrolateral region and sometimes another row of nodes on the inner flank, the new genus D has only one row of nodes, located on each side immediately adjacent to the median longitudinal groove, but lacks another row in the ventrolateral region. With a simplification of the sculpture, the new genus may be derived from Tainoceras. Corotainoceras also shows simplification of the sculpture, but differs from the new genus D in the absence of ventrolateral nodes and the presence of very coarse dorsolateral nodes.