Granulina sigridae, Elm & Hoffman, 2024

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 : 285-287

Granulina sigridae sp. nov.

urn:lsid:zoobank.org:act:420DB463-5D47-4231-8FF5-8117234B3C0A

Figs 5 , 9

Diagnosis

Small shell, height maximum 3.2 mm, width maximum 1.8 mm (width/height ratio 0.56), tumidity maximum 1.6 mm, ovoid oblong shape with convex labial bulge at apex; no labial denticles on interior of external lip, weakly rostrated apically and abapically, widely channelled abapically, colour white, translucent.

Etymology

The name (feminine) of the species acknowledges Sigrid Hof, technical assistant at the Senckenberg Museum Frankfurt, who performed the preliminary sorting of the Meteor samples.

Type material

Holotype

MAURITANIA – Timiris deep coral mound chain • 1 shell; 18.9624° N, 16.8704° W; depth 548 m; MSM16–3 stn GeoB14876; box core in coral rubble with mud; SMF359034 .

Paratypes (8 shells)

MAURITANIA – Timiris deep coral mound chain • 6 shells; same collection data as for holotype; SEM, SMF373040 • 11 shells same collection data as for holotype; SMF373042 • 2 shells; 18.9634° N, 16.8688° W; depth 498 m; 11 Nov. 2010; MSM16–3 stn GeoB14877; box core in coral rubble with mud; RMNH.MOL.351816 .

Other material examined (61 shells)

MAURITANIA – Banc d’Arguin • 1 shell; 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.351817 • 2 shells; Tanoudert Canyon ; 20.2429° N, 17.6681° W; depth 490 m; 3 Nov. 2010; MSM16–3 stn GeoB14799; box core in coral rubble with mud; SaM . – Banda Mound Complex • 1 shell; 17.6459° N, 16.6665° W; depth 442 m; 7 Jan. 2007; POS346 stn GeoB11564; box core in mud with coral rubble; SaM • 3 shells; 17.6501° N, 16.6681° W; depth 441 m; 7 Jan. 2007; POS346 stn GeoB11566; box core in mud with coral rubble; SaM • 1 shell; 17.6585° N, 16.6678° W; depth 428 m; 7 Jan. 2007; POS346 stn GeoB11567; box core in coral rubble with mud; SaM • 1 shell ; 17.6668° N, 16.6721° W; depth 440 m; 8 Jan. 2007; POS346 stn GeoB11569; box core in coral rubble with mud; SaM • 1 shell ; 17.6794° N, 16.6684° W; depth 450 m; 8 Jan. 2007; POS346 stn GeoB11579; box core in coral rubble with mud; SaM • 1 shell ; 17.684° N, 16.668°W; depth 481 m; 8 Jan. 2007; POS346 stn GeoB11580; box core in mud with coral rubble; SaM • 34 shells; Banda Slide ; 17.541° N, 16.6666° W; depth 486 m; 15 Nov. 2010; MSM16–3 stn GeoB14905; box core in coral rubble with mud; SaM . – Tamxat Mound Complex • 11 shells; C–Tamxat Mounds ; 17.5427° N, 16.6634° W; depth 510 m; 15 Nov. 2010; MSM16–3 stn GeoB14904; box core in coral rubble with mud; SaM • 5 shells; S–Tamxat Mounds ; 17.4833° N, 16.6941° W; depth 535 m; 15 Nov. 2010; MSM16–3 stn GeoB14910; box core in mud; SaM .

Description

Apex with weakly convex, blunt, narrowing channel. External lip smoothly rounded, thickened from apex to base, protruding and maximum convexity slightly above periphery, reclining towards apex and base, widely channelled at highly convex base, pointed at base columella, internally smooth (without labial denticles). Four spiral folds at base of straight columella, upper two folds are coalescent yet distinct. Parietal area widely convex and smooth. Macroscopic sculpture smooth with microscopic irregular growth lines; microscopic sculpture of flakes oriented towards exterior on callus of external lip, columella and columellar folds, base and apex, callus reclining in parietal area; internally smooth. Aperture curved, elongated, narrowest and maximum curvature at apex, wide at base. Protoconch invisible, convolved inside shell.

Remarks

Similar to the other new species, Granulina sigridae sp. nov. has no labial denticles, but the shell morphology is different. The shell is not as wide (width/height ratio 0.56) as in G. sandrae sp. nov. (0.69) and it lacks the widely flared apical channel like in G. reginae sp. nov. Granulina sigridae is similar to G. occulta but that species has labial denticles and it lacks the wide channel at the base. Granulina ronaldi sp. nov. has separated columellar folds, an apex with more convexity, a base that is more tapered, and has a thicker lip.

The bathymetric range is 200–548 m; the latitudinal range is 17.4– 20.4° N. Most of the specimens were found in coral rubble with mud and an association with upper bathyal coral–related habitats is likely.

Figures

Fig. 5. Location map of the new species in Granulina Jousseaume, 1888 off Mauritania and Western Sahara. White circles show all investigated stations; colour symbols show locations of shells from new species. Granulina reginae sp. nov. is presented by yellow squares, G. sigridae sp. nov. as red diamonds, G. sandrae sp. nov. as blue triangles, and G. ronaldi sp. nov. as green circles. Bathymetric data from GEBCO; contours 500 m

Fig. 9. Granulina sigridae sp. nov., Mauritania.A–I. Timiris coral mound chain, MSM16–3/GeoB14876. A–B. Paratype (SMF373040). A. Ventral view, height 2.9 mm, width 1.8 mm. B. Columellar folds. C–D. Holotype (SMF359034). C. Ventral view, height 3.1 mm, width 1.9 mm. D. Columellar folds. E– G. Paratype (SMF373040).E–F. Ventral and side views, height 3.2 mm, width 1.8 mm, tumidity 1.6 mm. G. Micro-sculpture above second columellar tooth, see arrow in E–F. H. Paratype (SMF373040), ventral view, height 3.0 mm, width 1.8 mm. I. Paratype (SMF373040), side view, height 3.1 mm, tumidity 1.6 mm. J–K. Tamxat Mounds, MSM16–3/GeoB14904, ventral view, height 2.8 mm, width 1.7 mm.