| Measurements | D mm | H/D | T/D | O/D | H/T |
|---|---|---|---|---|---|
| CP-130 | 20.3 | 0.43 | 0.36 | 0.26 | 1.19 |
| Age | Origin |
|---|---|
|
Grey clay, lyelli subzone benettianus zone Beginning of Middle Albian |
Brévonnes Aube France |
| Measurements | D mm | H/D | T/D | O/D | H/T |
|---|---|---|---|---|---|
| CP-130 | 20.3 | 0.43 | 0.36 | 0.26 | 1.19 |
| Age | Origin |
|---|---|
|
Grey clay, lyelli subzone benettianus zone Beginning of Middle Albian |
Brévonnes Aube France |
Description. A small pyritic phragmocone, unfortunately cracked due to inexorable decay of pyrite. It has a compressed and involute shape, with whorls two-thirds covered, and a smooth siphonal keel. At the beginning of last whorl, the section is trapezoidal, a bit compressed, with flanks converging towards the venter (convex if the keel is ignored), and maximum thickness at the inner third. Towards the end of the whorl, the flanks become rounded, the venter flattens, and the maximum thickness rises to mid-flank. The umbilicus has a rather low wall, vertical at the base then rounding towards the flank. 23 simple, thin, proverse, and slightly flexuous ribs arise at the umbilical suture, with wider interspaces. Without umbilical tubercles, they gradually widen towards the top of the flanks, at the expense of the interspaces which become narrow, then they curve forward (especially close to the aperture), form a blunt tubercle on ventrolateral shoulders and finally collapse at the base of the keel.
Remarques. Personal discovery. Cooper (1982) created the subgenus Mirapelia for this species with simple ribs, broadened and flattened towards venter. At the top of ventral view, the last two ribs of our CP-130 rise higher than the base of the keel, as in Mojsisoviczia delaruei (d'Orbigny, 1841). Matrion (2010) reports such borderline specimens in the lyelli subzone of Aube, still too young to recognize the exact species. But his photographs and those of Amédro et al. (2014) show that O. (M.) mirapelianum can also have these elevated ribs (ibid., pl. 5, fig. 7), while M. delaruei has a rather hexagonal section and angular ventrolateral tubercles (ibid., pl. V, fig. 8-9). We therefore assign CP-130 to O. (M.) mirapelianum. In southeastern France, as at the Col de Paluel near Rosans (Hautes-Alpes), this species covers the entire Middle Albian. We have not found any specimens with measurements in the literature, for comparison.