Peripetoceras parum Korn & Ghaderi, 2025, sp. nov.

Peripetoceras parum sp. nov. urn:lsid:zoobank.org:act: 4E83F0AE-DC82-4664-A104-362C6A5809DD Fig. 45; Table 27 Diagnosis Species of Peripetoceras with thickly pachyconic, subinvolute conch (ww/dm ~ 0.75; uw/dm ~ 0.15), weakly depressed whorl profile (ww/wh ~1.45) and extremely high coiling rate (WER ~2.65) at a conch diameter of 70 mm. Whorl profile rounded rectangular with flatly arched venter and flanks, broadly rounded ventrolateral shoulder and umbilical margin, convex umbilical wall and a moderately deep imprint zone (IZR ~0.25). Suture line with extremely shallow external and lateral lobe. Etymology From the Latin ‘ parum ’ (adjective, n.)= ‘even’; because of the nearly straight suture line. Type material Holotype IRAN – West Azerbaijan • Aras Valley; Vedioceras Beds of the Julfa Formation (late Wuchiapingian); 2011; Korn et al. leg.; illustrated in Fig. 45; MB.C.32072. Paratype IRAN – West Azerbaijan • 1 specimen; same data as for holotype; 2018; Ghaderi leg.; MB.C.32073. Description Holotype MB.C.32072 is a fairly complete but corroded specimen with a conch diameter of 70 mm (Fig. 45B). It is thickly pachyconic and subinvolute (ww/dm = 0.77; uw/dm = 0.16). The conch is expanding rapidly and has a very high coiling rate (WER = 2.67). On the last volution there are some changes in the shape of the whorl profile observable: while the cross section at the beginning of the last whorl is rather circular, at the end it is depressed (ww/wh= 1.44) with a flattened venter and slightly flattened flanks. The ventrolateral shoulder is rounded, as is the umbilical margin; the umbilical wall is steep and slightly flattened (Fig. 45A). The suture line extends with shallow undulation and possesses very shallow external and lateral lobes (Fig. 45C). Remarks Peripetoceras parum sp. nov. differs from the other Late Permian species of the genus in its general conch shape. Peripetoceras comploji and P. gigas are stouter and narrower umbilicate (ww/dm ~ 0.85; uw/dm ~0.10) than P. parum (ww/dm ~0.75; uw/dm ~0.15). However, it should be noted that the first two species were described from very large specimens, approximately twice the size of the holotype of P. parum. Peripetoceras freieslebeni has a slenderer conch (ww/dm ~ 0.65) than P. parum. The two Roadian species P. ideliense and P. burovi have a significantly larger umbilicus (uw/dm ~0.30) than P. parum sp. nov. Of the Kungurian species P. wanneri and P. brouweri, the former is slenderer (ww/dm ~0.70) and the latter is stouter (ww/dm ~ 0.85). Peripetoceras parum sp. nov. also differs from P. wanneri in having a much more rounded ventrolateral shoulder and less clearly flattened flanks and venter.