| Measurements | D mm | H/D | T/D | O/D | H/T |
|---|---|---|---|---|---|
| CP-418 | 62.2 | 0.45 | 0.30 | 0.27 | 1.49 |
| At.P.4F3 Mosavinia | 67.0 | 0.46 | 0.28 | 0.23 | 1.64 |
| CP-395 | 68.5 | 0.41 | 0.33 | 0.28 | 1.22 |
| Holotype Saveliev | 70.5 | 0.46 | 0.33 | 0.23 | 1.39 |
| At.Gl.12 Mosavinia | 86.0 | 0.50 | 0.30 | 0.23 | 1.67 |
| Age | Origin |
|---|---|
|
Sandstone nodules in sands Limit Middle and Upper Albian A. rossicus and S. litschkovi zones |
North-Aktau Ridge Mangystau Péninsula Kazakhstan |
Description. A semi-evolute ammonite with an orange-brown test, embedded in fine-grained gray sandstone. The whorls overlap by 50%, less at the end because the body chamber, occupying the last half-whorl, contracts slightly on the inner side. The whorl section is compressed trapezoidal with a flat venter. The flanks are slightly more convergent on the outer quarter. The rather high umbilical wall, sloping at 45°, has a rounded edge bearing nine very prominent spiny bullae, increasingly elongated and proverse over the body chamber. The whorl section is thickest at these bullae. The last whorl passes just above the bullae of the preceding whorl. Each bulla gives rise to one or two ribs, radial then sigmoid, broadened and flattened at the top of the flanks, with a steeper posterior slope. Intermediate ribs are also present, with fuzzy connections to the bullae or originating higher up, at mid-flank. In total, 21 ribs terminate in elongated, low ventrolateral clavi, almost parallel to the siphon and alternating on either side. The ribs exhibit a forward fold on the body chamber, in the outer quarter of the flanks. The intercostal space deepens upwards and notches the ventral edge, giving it a zigzag appearance.
Remarks. The species was named Anahoplites solidus by Saveliev, then Semenoviceras solidus (sic) by Mosavinia et al. (2014). It is indeed a Semenoviceras, given its prominent bullae and flattened ribs near venter. This ammonite from Iran and Mangystau occurs alongside Anahoplites rossicus, biplicatus, and sinzowi in the upper Middle Albian, and then Semenoviceras tamalakense (see its entry) in the lower Upper Albian. It is the thickest Semenoviceras (T/D ≈ 0.30) after S. baisunensis (Luppov, 1961), which is involute, with more convergent flanks, a less wide venter and many more ribs (35-40).