Gymnobela multilirata, 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 : 537-538

Gymnobela multilirata n. sp.

( Fig. 21 A-E)

urn:lsid:zoobank.org:act:3B5B70FF-0A68-4463-9076-1306DEBC2C7E

TYPE MATERIAL. — Holotype. sh., MNHN-IM-2000-34274 . Paratypes. 10 sh., MNHN-IM-2000-34275 from SEAMOUNT 2 DW130 .

TYPE LOCALITY. — Off W Gran Canaria, 28°08.95’N, 15°53.11’W / 28°09.06’N, 15°52.92’W, 655- 660 m.

ETYMOLOGY. — An adjective formed from the Latin lira, a furrow, based on the sculpture with numerous spiral furrows.

OTHER MATERIAL EXAMINED. — 66 sh., SEAMOUNT 2 DW130.

DESCRIPTION

Shell small, whitish, consisting of a little more than three convex, definitely shouldered whorls, with a well marked suture; protoconch (visible part 550 µm high, 400 µm diameter) protruding and somewhat pointed apically, formed of a little more than one whorl, nearly smooth on the initial part but mostly covered by minute, irregular granules which are loosely aligned spirally. Protoconch/teleoconch limit very definite along an orthocline line. Teleoconch with elevated spiral cords, of which 4-5 on the spire whorls and 19-21 on the last whorl; cords narrower than the interspaces, one along the suture, the strongest one on the shoulder and the 2-3 abapical ones decreasing slightly in size; on the last half-whorl, an additional cord between the suture and the shoulder. The entire teleoconch covered by axial wrinkles which are much finer than the cords and override them. Aperture oval-elongate, somewhat truncated adapically at the shoulder of last whorl; outer lip simple, siphonal canal short and very broad. Dimensions of the holotype: 2.2 mm height × 1.15 mm diameter, paratypes up to 2.7 × 1.5 mm.

REMARKS

“ Gymnobela ” multilirata n. sp., does not resemble closely any Atlantic species known to us, and even the generic and familial placement is tentative. It is guided by the overall resemblance with species like e.g. Gymnobela subaraneosa (Dautzenberg & H. Fischer, 1896) or G. lamyi (Dautzenberg, 1925) (see Bouchet & Warén 1980: 52) which also have a definite shoulder and a sculpture of widely separated spiral cords. Another superficially similar species is Nepotilla amoena (G. O. Sars, 1878) (see Bouchet & Warén 1980: 75, 76) but the latter has fewer and much stronger spirals and a much narrower canal and abapical part. The paucispiral protoconch of G. multilirata n. sp. is typical of a species with non-planktotrophic larval development but does not give a definite clue, although the profile of the protoconch and its definite, orthocline edge resembles the cancellariid Pseudobabylonella minima (Reeve, 1856) (see Verhecken 2007: 351). However, teleoconch characters including the lack of folds on the columella and the elongate, tapering last whorl (usually blunt and short in cancellariids) do not support a placement in the latter family. Despite the uncertainty on its position, we consider this species as distinctive and abundant so as to be named.

Figures

FIG. 21. — A, B, Gymnobela multilirata n. sp., holotype from DW130 (height 2.2 mm); C, D, paratype, same locality (height 2.7 mm); E, protoconch of another paratype, same locality. Scale bar: 200 µm.