Nautilida

New genus A Korn & Hairapetian (in press) Type species New species E to be described by Korn & Hairapetian (in press); original designation. Diagnosis Genus of the new family to be described by Korn & Hairapetian (in press) with a subinvolute conch. Extremely to extraordinarily high coiling rate; whorl profile inverted trapezoidal, weakly compressed or weakly depressed with concave or flat venter and flattened, convergent flanks. Sculpture in the adult stage absent; in the juvenile stage sometimes with short ribs on the flank. Suture line with a shallow to deep V-shaped external lobe and a broadly rounded lateral lobe (from Korn & Hairapetian in press). Included species Central Iran (Korn & Hairapetian in press): new species E to be described by Korn & Hairapetian (in press), Wuchiapingian; new species F to be described by Korn & Hairapetian (in press), Wuchiapingian; new species G to be described by Korn & Hairapetian (in press), Wuchiapingian. Remarks According to Korn & Hairapetian (in press), the new genus A can hardly be confused with any other genus of Late Permian nautilids because of its very characteristic conch shape. The rather sharp umbilical margin, the flattened and rapidly converging flanks, the angular, skid-like ventrolateral shoulder and the more or less clearly concave venter allow a clear separation. Pseudotitanoceras is similar, but this genus is distinguished from the new genus by the presence of tubercles on the ventrolateral shoulder. Shimansky (1965b) mentioned that among his material of P. armeniacum there were also specimens without ventrolateral tubercles. Perhaps these do belong to the new genus rather than Pseudotitanoceras.