Permonautilus Kruglov 1933

Genus Permonautilus Kruglov, 1933 Type species Nautilus cornutus Golovkinsky, 1868; original designation. Diagnosis Genus of the family Permonautilidae with pachyconic or globular, usually subinvolute to subevolute conch. Whorl profile in the adult stage usually more or less strongly depressed; flanks and venter form a continuous arch in the early forms, the venter can be flattened or concave in advanced forms. Terminal aperture with long lateral shell processes emerging from the umbilical margin. Ornament consisting of fine or coarse growth lines. Septum simple in shape, concavely domed; suture line very simple, almost straight across flanks and venter or with small lobes and saddles (from Korn & Ghaderi 2025). Included species Greenland (Tichy 1975): Permonautilus halleri Tichy, 1975, Wuchiapingian. Western Russia (Golovkinsky 1868; Kruglov 1933; Barskov et al. 2014): Nautilus cornutus Golovkinsky 1868, Roadian; Permonautilus pinegaensis Kruglov, 1933, Roadian; Permonautilus parapinegaensis Barskov & Shilovsky, 2014, Roadian; Permonautilus kruglovi Barskov & Shilovsky, 2014, Roadian. Transcaucasia (Kruglov 1933): Coloceras Abichi Kruglov, 1928, Wuchiapingian, Azerbaijan. Central Iran (this paper): Permonautilus adelphidus sp. nov., Wuchiapingian. Remarks The species of Permonautilus have very similar morphology; differences lie in the width of the conch, the width of the umbilicus and the shape of the whorl profile. The genus is currently only known from the two Permian stages Roadian and Wuchiapingian; no representatives have yet been reported from the Wordian and Capitanian stages in between.