| Measurements | D mm | H/D | T/D | O/D | H/T |
|---|---|---|---|---|---|
| CP-404 | 51.5 | 0.43 | 0.45 | 0.26 | 0.95 |
| CP-363 | 57.5 | 0.39 | 0.42 | 0.33 | 0.92 |
| CP-368 | 60.9 | 0.39 | 0.44 | 0.31 | 0.88 |
| CP-361 | 68.9 | 0.38 | 0.42 | 0.33 | 0.90 |
| Holotype | 73.0 | 0.37 | 0.43 | 0.23 | 0.82 |
| Age | Origin |
|---|---|
|
O. sinzowi zone, P. (H.) puzosianus subzone in Mangystau. puzosianus zone in ABP. Lower Albian |
North-Aktau Ridge Mangystau Peninsula Kazakhstan |
Description. Whorls barely depressed, square in cross-section with rounded corners, overlapping by 50%. The gray body chamber no longer widens and tends to uncoil. Ribs arched, slightly proverse, sharp, increasingly tall, with a steeper posterior slope than anterior. Originating in pairs from elongated umbilical tubercles, they pass through the venter with a broad, shallow sinus. The angle of bifurcation increases, and more and more isolated ribs are observed, especially on the body chamber. The ribs are taller on venter, and a very fine groove cuts into their crest along the siphonal line, like a scratch: it begins at the start of last whorl and disappears before the end. There are 17 tubercles and 23 ribs. We show on the right the unpublished suture line (specimen 404 at 34 mm).
Remarks. Casey (1952) created the genus Tetrahoplites from the Sonneratia jachromensis and subquadrata depicted by Sinzow (1907), and T. subquadratus for the Sonneratia subquadrata in plate III of Sinzow, figures 7-8. By compressing the section, we arrive at T. orientalis and then T. suborientalis, which are perhaps variants (see their entries). The species is common in Transcaspia but appears to be very rare in Western Europe: the literature mentions only one T. cf. subquadratus from Kent (Casey, 1965). The MNHN database lists another from Andon in the Alpes-Maritimes (d'Orbigny collection A25643).