Granulina 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 : 271-274

Granulina crassa Smriglio, Gubbioli & Mariottini, 2000

Figs 1 , 3

Granulina crassa Smriglio, Gubbioli & Mariottini, 2000: 55 , figs 2, 9–12; type locality: off Mauritania, 80– 100 m.

Smriglio et al. (2000) reported 14 type specimens, of which some empty shells from off Mauritania (80– 100 m) and off Western Sahara (50 m) without further details. The holotype was deposited in Bologna Zoology Museum (MZB14030). Thirteen paratypes were retained in private collections.

Material examined (509 shells)

MAURITANIA – Banc d’Arguin • 5 shells; 20.3667° N, 17.6667° W; depth 200 m; 28 Oct. 1978; CANCAP stn 3.120; sandy clay with shells; van Veen grab; RMNH.MOL.351803 • 12 shells; 18.9833° N, 16.8333° W; depth 203 m; 30 Oct. 1978; CANCAP stn 3.140; sandy clay with shells; van Veen grab; RMNH.MOL.351804 • 3 shells; 18.9833° N, 16.8333° W; depth 203 m; 30 Oct. 1978; CANCAP stn 3.140; sandy clay with shells by van Veen grab; RMNH.MOL.351805 • 28 shells; 19.35° N, 16.9333° W; depth 200 m; 31 Oct. 1978; CANCAP stn 3.154; sandy clay with shells; van Veen grab; RMNH.MOL.351806 • 60 shells; 19.94° N, 17.48° W; depth 151 m; 22 May 1988; Tyro Mauritania I stn B5; SaM • 2 shells; Arguin mud wedge; 20.2353° N, 17.6029° W; depth 111 m; 24 Oct. 2010; MSM16–3 stn GeoB14703; box core in muddy silt; SaM • 40 shells; Arguin mud wedge; 20.4569° N, 17.6795° W; depth 142 m; 24 Oct. 2010; MSM16–3 stn GeoB14706; box core in muddy silt; SaM • 1 shell; Baie du Levrier ; 20.8169° N, 17.0186° W; depth 13 m; 31 Oct. 2010; MSM16– 3 stn GeoB14780; bottom grab in muddy silt; SaM • 1 shell; southern Banc d'Arguin; 19.7967° N, 17.2034° W; depth 105 m; 6 Nov. 2010; MSM16–3 stn GeoB14850; box core in muddy silt; SaM. – Timiris mud wedge • 2 shells; 19.5506° N, 16.9731° W; depth 100 m; 8 Nov. 2010; MSM16– 3 stn GeoB14866; box core in silty sand; SaM. – Banda Mound Complex • 1 shell; 17.6699° N, 16.6736° W; depth 505 m; 14 Nov. 2010; MSM16–3 stn GeoB14898; bottom grab in muddy silt; SaM. – off Nouakchott • 3 shells; 17.045° N, 16.7783° W; depth 202 m; 11 Feb. 1977; M44 stn 133–KG613; box core; SMF • 5 shells; 17.045° N, 16.7783° W; depth 208 m; 11 Feb. 1977; M44 stn 133–KG615; box core; SMF • 1 shell; 17.0817° N, 16.775° W; depth 312 m; 12 Feb. 1977; M44 stn 135–KG625; box core; SMF • 25 shells; 17.0967° N, 16.73° W; depth 127 m; 17 Feb. 1977; M44 stn 193–KG626; box core; SMF • 5 shells; 17.0967° N, 16.73° W; depth 126 m; 17 Feb. 1977; M44 stn 193–KG627; box core; SMF • 72 shells; off Nouakchott ; 17.2783° N, 16.4483° W; depth 87 m; 13 Feb. 1982; M60 stn 77–KG960; box core; SMF • 85 shells; 17.2783° N, 16.4483° W; depth 88 m; 13 Feb. 1982; M60 stn 77–KG961; box core; SMF • 55 shells; 17.2783° N, 16.4483° W; depth 87 m; 13 Feb. 1982; M60 stn 77–KG965; box core; SMF .

WESTERN SAHARA – off Cap Blanc • 62 shells; 21.325° N, 17.37° W; depth 81 m; 25 Feb. 1977; M44 stn 235–KG649; box core; SMF • 1 shell; 21.7683° N, 17.4333° W; depth 125 m; 20 Feb. 1982; M60 stn 88–KAD268; SMF. – North of Dakhla • 39 shells; 25.0000° N, 15.5167° W; depth 53 m; 21 Feb. 1975; M36 stn 94–KG2; box core; SMF • 1 shell; 25.18333° N; 15.80333° W; depth 87 m; 22 Feb. 1975; M36 stn 95–KG6; box core; SMF .

Remarks

Smriglio et al. (2000) indicated a holotype height of 1.9 mm; our set indicates a maximum height of 2.1 mm. The species is the smallest member of the four coffin-shaped species from Mauritania. It has very weak labial denticles that occasionally may be absent, even though these specimens may be subadult. Granulina crassa lacks an (ab-)apical rostration.

The species is known from empty shells in the latitudinal range 17.0– 25.2° N. The full bathymetric range is 13–505 m; it is commonly found on the lower shelf at depths of 80–210 m in silty sand.

Figures

Fig. 1. Location map of the known species of Granulina Jousseaume, 1888 found off Mauritania and Western Sahara. All investigated stations are shown by white circles; specimens of Granulina were only found at locations indicated by colour symbols. Granulina cerea Smriglio, Gubbioli & Mariottini, 2000 is presented as yellow squares, G. crassa Smriglio, Gubbioli & Mariottini, 2000 as red diamonds, G. crystallina Smriglio, Gubbioli & Mariottini, 2000 as blue triangles and G. nofronii Smriglio, Gubbioli & Mariottini, 2000 as green circles. Bathymetric data from GEBCO, contours at 500 m intervals.

Fig. 3. Granulina crassa Smriglio, Gubbioli & Mariottini, 2000, Western Sahara, off Cap Blanc, M44/235–KG649. A–D. Ventral and side views, height 2.1 mm, width 1.3 mm, tumidity 1.0 mm. C. Columellar folds. D. Micro–sculpture above second columellar fold, see arrow in C. E–F. Ventral and side views, height 2.1 mm, width 1.3 mm, tumidity 1.0 mm.G–H. Views and dimensions as E–F. I– J. Views and dimensions as E–F.