Dzhulfites spinosus Shevyrev, 1965

Fig. 22; Table 7

Dzhulfites spinosus Shevyrev, 1965: 173, pl. 21 fig. 9, pl. 22 fig. 1.

Dzhulfites spinosus – Shevyrev 1968: 88, pl. 2 figs 3–4. — Korn et al. 2019: 51, text-figs 20–21.

Diagnosis

Species of Dzhulfites with conch reaching 90 mm dm. Subadult stage with weakly trapezoidal, moderately depressed whorl profile (ww/wh =1.50–1.60) and broadly rounded venter; 6–8 coarse conical nodes on midflank per volution. Prongs of external lobe simple to trifid; altogether 14–18 notches of E, A and L lobes.

Type material

Holotype AZERBAIJAN • Nakhichevan Province, Dorasham 2 section; Late Permian; illustrated by Shevyrev (1965: pl. 21 fig. 9); PIN 1478/60.

Material examined

IRAN • 1 specimen; Esfahan Province, Baghuk Mountain 1 section; Hambast Formation; MB.C.29738 • 1 specimen; Esfahan Province, Baghuk Mountain A section; Hambast Formation; MB.C.29739 • 1 specimen; Esfahan Province, Baghuk Mountain B section; Hambast Formation; MB.C.29740 • 2 specimens; Esfahan Province, Baghuk Mountain E section; Hambast Formation; MB.C.29741 to MB.C.29742 • 1 specimen; Esfahan Province, Baghuk Mountain G section; Hambast Formation; MB.C.29743 • 2 specimens; Esfahan Province, Baghuk Mountain G section; Hambast Formation; MB.C.29744 to MB.C.29745.

Description

Specimen MB.C.29739 has a conch diameter of 47 mm, but the beginning of the terminal body chamber is already at 31 mm, as indicated by two narrowly spaced septa (Fig. 22B). The weakly corroded specimen shows a ww/wh ratio of 1.50 at 32 mm dm; the whorl profile is trapezoidal with broadly rounded venter. The sculpture possesses six as well as eight conical midflank nodes on the last two volutions of the phragmocone, respectively.

The suture line of specimen MB.C.29739 has an external lobe that is almost as deep as the adventive lobe; it possesses three small notches. There follow an inverted U-shaped ventrolateral saddle and an adventive lobe that is widest at its base. It has about eight small notches. The parallel-sided lateral saddle is lower than the ventrolateral saddle and the lateral lobe, subdivided by seven very small notches, is only half as deep as the adventive lobe (Fig. 22F).

Specimen MB.C.29743 is a specimen with 48 mm conch diameter and has a phragmocone diameter of 36 mm (Fig. 22C). Its body chamber has a rounded-trapezoidal, weakly depressed whorl profile (ww/ wh= 1.30) with broadly rounded venter. In the subadult stage, the ww/wh ratio is higher than 1.50 and the whorl profile has a depressed oval shape. The sculpture in the subadult stage has eight coarse and pointed conical midflank nodes per volution; these nodes become much weaker on the body chamber and are replaced by weak, radial ribs, which are coarsest in the ventrolateral region.

The suture line of specimen MB.C.29743 differs from the preceding in the simple, unsubdivided prongs of the external lobe that is not as deep as the adventive lobe, the inflated ventrolateral saddle and the wider lateral saddle (Fig. 22E).

The suture line of the smaller specimen MB.C.29744 is remarkable because of its asymmetric external lobe with one prong being unsubdivided and the other possessing three small notches. It shows a narrow, dorsally inclined and weakly inflated ventrolateral saddle and a multiply serrated, asymmetric adventive lobe that is widest at its base (Fig. 22G).

Remarks

Dzhulfites spinosus differs most of the other species of Dzhulfites in the shape of the venter, which is broadly rounded in the new species but more or less flattened in D. nodosus and D. zalensis. Dzhulfites hebes is a very similar species in conch proportions and sculpture, but differs in the coarser, blunt nodes of the sculpture. Paratirolites kittli is a species with similar conch morphology, but possesses a deep external lobe, which is much shorter in D. spinosus.

Stratigraphic range

Upper part of the Hambast Formation; 7.00 to 4.70 m below the extinction horizon (Dzhulfites spinosus Zone to Shevyrevites shevyrevi Zone).