Prunum similerato, Ortega & Gofas, 2019

Ortega, José Rafael & Gofas, Serge, 2019, The unknown bathyal of the Canaries: new species and new records of deep-sea Mollusca, Zoosystema 41 (26), pp. 513-551 : 534-535

Prunum similerato n. sp.

( Fig. 18 A-D)

urn:lsid:zoobank.org:act:EEFC8B2F-641B-4243-8F8C-32C56B788BEE

TYPE MATERIAL. — Holotype. sh., MNHN-IM-2000-34267 . Paratypes. 6 sh., MNHN-IM-2000-34268, SEAMOUNT 2 DW126 ; 1 sh., MNHN-IM-2000-34279, DW129 .

TYPE LOCALITY. — Off NW Gran Canaria, 28°07.59’N, 15°52.05’W / 28°07.66’N, 15°52.02’W, 345 m.

ETYMOLOGY. — The name alludes to the outline which recalls some species of the genus Erato .

DESCRIPTION

Shell small, consisting of nearly 4 whorls, yellowish to greyish white and opaque in dead shells, smooth, with a rather low spire. Apex blunt and rounded, protoconch about 1 mm in diameter, consisting of 1 1/4 whorl, delimited from teleoconch by a tenuous line. Spire whorls hardly convex, with a thin suture. Last whorl representing about 90% of total height. Aperture elongate, narrow and parallel-sided. Outer lip smooth inside, bordered externally by thin labial varix, slightly receding at its adapical end, forming there a broadly rounded shoulder against the penultimate whorl. There are four columellar plaits occupying less than half of the aperture length, the adapical one relatively thin, the other three stout with a flattened crest. A broad and thin columellar callus covering the part of the last whorl adjacent to the aperture.Dimensions of holotype: 6.9 mm height × 4.15 mm diameter, of figured paratype 7.3 × 4.5 mm.

REMARKS

Only worn shells were collected, so that this species may live shallower and shells have been transported down the steep slope. This species, with a very embracing last whorl, is tentatively assigned to Prunum , as it shares with other (mostly Caribbean: see Cossignani 2006: 196-206) species the stout, ovoid outline with a conspicuous and tapering last whorl, and the smooth inner part of the outer lip. Admittedly, the separation between the genera Prunum and Volvarina Hinds, 1844 is not clear-cut and currently follows a rather arbitrary criterion where the large species with a strong callus are placed in Prunum , the slender species with a thin callus in Volvarina , leaving in between many ambiguously placed species like the one considered here.

Several species of Prunum (summarized in Espinosa et al. 2014) have been described from the Canaries, namely P. estefaniae Pérez-Dionis, Ortea & Espinosa, 2009 , P. nataliae Pérez-Dionis, Ortea & Espinosa, 2009 , P. javii Espinosa, Ortea & Moro, 2013 , P. montseae Espinosa, Ortea & Moro, 2014 , P.pacotalaverai Espinosa, Ortea & Moro, 2014 and the fossil (of unspecified Plio-Pleistocene age) P. clarae Contreras, 1994 , but all of them are littoral species previously confounded with Prunum olivaeforme (Kiener, 1834) or others from the West African mainland.

Figures

FIG. 18. — Prunum similerato n. sp., A, B, holotype (sh.) from DW126 (height 6.9 mm); C, D, paratype (sh.) from DW129 (7.3 mm).