Granulina sandrae sp. nov.

urn:lsid:zoobank.org:act: 1D97D3ED-F5D5-466B-9008-C0B9F63CAEAF

Figs 5, 8

Diagnosis

Small shell, height maximum 3.6 mm, width maximum 2.5 mm (width/height ratio 0.69), tumidity maximum 2.0 mm; colour white; outline pear-shaped, apex slightly pointed and weakly rostrated, base widely channelled.

Etymology

The name (feminine) of the species acknowledges Sandra Müller, technical assistant at the Senckenberg Museum Frankfurt, who has been the key person incorporating the SaM samples into the SMF collection.

Type material

Holotype

MAURITANIA • Banc d’Arguin; 19.35° N, 16.9333° W; depth 200 m; 31 Oct. 1978; CANCAP stn 3.154; sandy clay with shells; van Veen grab; SMF359030.

Paratypes (10 shells)

MAURITANIA – Banc d’Arguin • 2 shells; same data as type locality; SMF359031 • 1 shell; same collection data as for holotype; RMNH.MOL.351812 • 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.351813 • 1 shell; 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.351814 • 2 shells; 19.3667° N, 16.85° W; depth 200 m; 31 Oct. 1978; CANCAP stn 3.155; sandy clay with shell gravel; van Veen grab; RMNH.MOL.351815 • 1 shell; deep mound chain off Banc d’Arguin; 19.8107° N, 17.4705° W; depth 1310 m; 7 Nov. 2010; MSM16–3 stn GeoB14852; box core; SMF 359035 • 1 shell; Arguin South 3 Canyon; 19.7381° N, 17.1465° W; depth 483 m; 7 Nov. 2010; MSM16–3 stn GeoB14858; bottom grab; SMF 359032 . – Timiris Mound Complex • 2 shells; 19.8524° N, 17.2636° W; depth 369 m; 6 Nov. 2010; MSM16– 3 stn GeoB14847; box core in muddy silt; SMF 359033 .

Other material examined (21 shells)

MAURITANIA – Timiris Mound Complex • 1 shell; 18.9832° N, 16.8636° W; depth 474 m; 9 Jan. 2007; POS346 stn GeoB11588; box core in coral rubble with mud; SaM . – Tamxat Mounds • 2 shells; 17.5427° N, 16.6634° W; depth 510 m; 15 Nov. 2010; MSM16–3 stn GeoB14904; box core in coral rubble with mud; SaM • 7 shells; 17.3017° N, 16.76° W; depth 411 m; 10 Feb. 1982; M60 stn 65–KG946; box core; SMF • 5 shells; 17.045° N, 16.7783° W; depth 208 m; 11 Feb. 1977; M44 stn 133–KG615; box core; SMF • 6 shells; 17.045° N, 16.7783° W; depth 199 m; 11 Feb. 1977; M44 stn 133–KG616; box core; SMF .

Description

Apex with highly convex, blunt, narrowing channel. External lip smoothly rounded, thickened from apex to base, protruding and maximum convexity well above periphery, reclining towards apex and base, internally smooth, without labial denticles. Four spiral folds at base of straight columella, upper two folds coalescent but still 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 the middle part; internally smooth. Aperture curved, elongated, narrowest at periphery, wide at base and narrower at apex. Protoconch invisible, convolved inside shell.

Remarks

Granulina boucheti Gofas, 1992 shows a morphological similarity to the new species; it has a similar size and outline but it differs by its labial denticles on the inside of the external lip; the present species lacks labial denticles. Granulina sigridae sp. nov. has a wide channel with less convex margin apically, and it is more elongated (width/height ratio 0.56 versus 0.69 in G. sandrae sp. nov.) with an even convexity in the outer lip.

The Pliocene Granulina iberica La Perna, Landau & Marquet, 2001 has a similar outline as the present species but it differs by the presence of fine labial teeth, a widely notched apical channel and an obliquely truncated apical outline. The present species shows a tapered apex.

Bathymetric range 199–1310 m; latitudinal range 17.0– 20.4° N. Some shells were found in sandy clay with other shells. Other shells were found in coral rubble with mud.