Dorsetensia? sp. [M]

(Fig. 14T)

MATERIAL EXAMINED. — JAC22.57.3 .

MEASUREMENTS. — See Table 27.

DESCRIPTION

Moderately evolute, whorl section compressed subrectangular with a low umbilical wall that almost matches the rounded umbilical edge. The flanks are gently convex and the ventral area is weakly tabulated with a moderately developed keel. The ribs, arising near the umbilical edge, somewhat irregular in thickness, are mainly simple but some tend to join in pairs near their base. Radial or only barely sinuous, they bend forward at the ventral edge. The ribbing weakens but does not disappear in the BC. The suture is not preserved.

REMARKS

The specimen described above displays common characters with Witchellia gr. laeviuscula (J. de C. Sowerby, 1824) and some primitive Dorsetensia such as D. pinguis (Roemer, 1836), D. hannoverana (Hiltermann, 1939), and D. hebridica Morton. W. laeviuscula has a similar ribbing style, but is more involute and has greater whorl expansion. Also, the section is subtriangular instead of subrectangular. Dorsetensia gr. pinguis specimens have similar coiling, but usually have more developed ribbing.

DISTRIBUTION

This specimen is from the upper part of the Laeviuscula Zone, and is therefore older than D. gr. pinguis, from the JAC22 section, Campillo de Arenas (Jaén Province).