Serometacoceras parvituberculatum, Korn & Ghaderi, 2025

Serometacoceras parvituberculatum gen. et sp. nov.

urn:lsid:zoobank.org:act:

Fig. 23 View Fig ; Table 13 View Table 13

Diagnosis

Species of Serometacoceras gen. nov. with thinly pachyconic, subevolute conch (ww/dm ~0.70; uw/dm ~ 0.35), moderately depressed whorl profile (ww/wh ~1.75) and very high coiling rate (WER ~ 2.40) at a conch diameter of 40 mm. Whorl profile rounded rectangular with flattened, gently divergent flanks; venter flatly rounded, flanks flattened, umbilical margin subangular. Sculpture with weak lateral ribs ending in small ventrolateral tubercles.

Etymology

Combination of the Latin ‘ parvum ’ (adjective, n.)=‘small’ and ‘ tuberculum ’ (noun, n.); because of the small ventrolateral tubercles.

Type material

Holotype

IRAN – East Azerbaijan • Zal ; Vedioceras Beds of the Julfa Formation ( late Wuchiapingian); 2018; Ghaderi leg.; illustrated in Fig. 23 View Fig ; MB.C.32052 .

Description

Holotype MB.C.32052 is a rather poorly preserved specimen with a conch diameter of 38 mm ( Fig. 23A View Fig ). It is thinly pachyconic (ww/dm = 0.70) and subevolute (uw/dm = 0.34) with a nearly rectangular, moderately depressed whorl profile (ww/wh =1.73) and a very high coiling rate (WER = 2.40). The whorls are widest at the umbilical margin, from where the weakly convex umbilical wall approaches the umbilical seam. The flanks converge slowly towards the pronounced, narrowly rounded ventrolateral shoulders; the venter is broadly arched ( Fig. 23B View Fig ). The main element of the sculpture consists of delicate lateral ribs ending in a series of small tubercles on the ventrolateral shoulder. The suture line is visible only on the flanks and the umbilical wall, both of which have very shallow, broadly rounded lobes.

Remarks

Serometacoceras parvituberculatum gen. et sp. nov. differs from the other species of the genus in the very small and more numerous ventrolateral tubercles.