Granulina aff. crassa, Smriglio, Gubbioli & Mariottini, 2000

Elm, Laura-Marie Von & Hoffman, Leon, 2024, Revision of deep-water species in Granulina (Gastropoda: Granulinidae) from Mauritania and Western Sahara, European Journal of Taxonomy 925, pp. 268-291 : 275-276

Granulina aff. crassa

Fig. 4

Diagnosis

Small shell, height maximum 2.0 mm, width maximum 1.3 mm, tumidity maximum 1.0 mm, pearshaped; labial denticles on interior of external lip, weakly rostrated apically and abapically, widely channelled abapically; 4 separated columellar folds; colour white.

Material examined (3 shells)

MAURITANIA – off Nouakchott • 1 shell; 17.045° N, 16.7783° W; depth 208 m; 11 Feb. 1977; M44 stn 133–KG615; box core; SMF373043 • 2 shells; 17.2783° N, 16.4483° W; depth 87 m; 13 Feb. 1982; M60 stn 77–KG960; box core; SMF373044 .

Description

Abapical end highly convex, blunt, widening channel; apical end less convex; external lip thick, angular above periphery, thickened from apex to base, protruding and maximum convexity slightly above periphery, reclining towards apex and base, widely channelled at highly convex base, internally smooth, weak to strong labial denticles. Four spiral folds at base of straight columella, lower two strongest extending across base, upper two folds small yet separated. Parietal area widely convex and smooth. Macroscopic sculpture smooth with microscopic irregular growth lines; microscopic sculpture of flakes oriented towards exterior on broad callus on external lip, columella and columellar folds, base and apex, callus reclining in parietal area; internally smooth. Aperture curved, elongated, narrowest slightly above periphery, wide at base.

Remarks

The present species is similar to Granulina crassa but its outline is less elongated and less angular and its callus is very well developed across the apex, base and the parietal area. The three shells show a great variability in outline; possibly we deal with more than one species.

We refrain from proposing a new species as we identified only three shells, two of which are eroded. The bathymetric range is 87–208 m; the latitudinal range is 17.0– 17.3° N, off Nouakchott.

Figures

Fig. 4. Ganulina aff. crassa, off Nouakchott, Mauritania. A–D. M44/133–KG615. E–F. M60/77–KG- 960. A–B. Ventral and side view, height 1.8 mm, width 1.2 mm, tumidity 1.0 mm. C. Micro-sculpture above second columellar fold, see arrow in D. D. Columellar folds and labial denticles. E. Ventral view, height 2.0 mm, width 1.3 mm. F. Ventral view, height 2.0 mm, width 1.3 mm.