Alibashites mojsisovicsi A. Lateral

Alibashites mojsisovicsi (Stoyanow, 1910)

Fig. 47; Table 23

Xenodiscus (Paratirolites ?) Mojsisovicsi Stoyanow, 1910: 79, pl. 8 fig. 1.

Abichites mojsisovicsi – Shevyrev 1965: 180, pl. 23 fig. 4; 1968: 95, pl. 4 fig. 3. — Stepanov et al. 1969: pl. 13 fig. 4.

Alibashites mojsisovicsi – Korn & Ghaderi in Korn et al. 2016: 870, text-fig. 29.

Alibashites with conch reaching 90 mm dm. Subadult stage with circular, weakly depressed whorl profile (ww/wh =1.00–1.20) and rounded venter; 13 coarse ventrolateral nodes per volution. Adult stage with quadrate and weakly compressed whorl profile (ww/wh=0.95–1.00), almost flat venter and subangular

ventrolateral shoulder; low ribs on flanks, forming very weak dorsolateral and ventrolateral nodes. Prongs of external lobe variable, simple to trifid; 8–13 notches of E, A and L lobes.

IRAN • 1 specimen; Esfahan Province, Baghuk Mountain C section; Hambast Formation; MB.C.29969 • 1 specimen; Esfahan Province, Baghuk Mountain H section; Hambast Formation; MB.C.299670 • 2 specimens; Esfahan Province, Baghuk Mountain; Hambast Formation; MB.C.299671 to MB.C.29972.

Specimen MB.C.29969 has 55 mm conch diameter with a moderately well-preserved last volution of the phragmocone but a weathered body chamber (Fig. 47A). It possesses a nearly quadrate whorl profile with angular ventrolateral shoulder and weakly concave venter at its largest diameter. Half of a whorl earlier, the venter is nearly flat and another half of a whorl earlier, it is broadly convex. At this stage, the whorl profile is trapezoidal with strongly diverging flanks. The sculpture of the phragmocone shows about 20 ventrolateral nodes with a tendency to become weaker during growth of the conch.

The suture line of specimen MB.C.29969 shows a V-shaped external lobe with diverging flanks, a parallel-sided ventrolateral saddle with weak dorsal inclination and adventive and lateral lobes with moderate serration (Fig. 47B). They are separated by a rather low, symmetric lateral saddle.

Alibashites ferdowsii also has coarse nodes in the subadult stage like A. mojsisovicsi, but this species shows a much wider whorl profile (ww/wh=1.25–1.50) than A. mojsisovicsi (ww/wh = 0.95–1.00) in the adult stage. A. mojsisovicsi differs from the species of Abichites, which may develop a similar adult stage, in the coarse subadult ventrolateral nodes.

Upper part of the Hambast Formation; 1.35 to 0.75 m below the extinction horizon (upper part of the Lutites profundus Zone to Abichites stoyanowi Zone).