Emarginula tenera Locard, 1892

Negri, Mauro Pietro & Corselli, Cesare, 2016, Bathyal Mollusca from the cold-water coral biotope of Santa Maria di Leuca (Apulian margin, southern Italy), Zootaxa 4186 (1), pp. 1-97 : 53

Emarginula tenera Locard, 1892

Fig. 11 r–t

Emarginula tenera Locard, 1892 (p. 224).

Emarginula tenera Locard, 1892 — Bogi & Giusti 1994 (p. 43, figs. 10–12); Giannuzzi-Savelli et al. 1994 (p. 48, fig. 84); Palazzi & Villari 2001 (p. 10, fig. 18); Repetto et al. 2005 (p. 76, bottom right fig.); Beck et al. 2006 (p. 39, bottom fig.).

Diagnostic characters. Elevated limpet-shaped shell; oval basal outline; recurved apex reaching the posterior margin; anal slit deep and adapically rounded; selenizone bordered by raised flanges; strong radial ribs gradually increasing in number by intercalation; weaker concentric ribs in the interspaces between the radials. Protoconch: planispiral, slightly turned to the right; slightly less than 1.25 whorls; diameter about 150 µm; flocculent to reticulated micro-ornament on early part of protoconch, later arranged roughly in collabral rows; transition to the teleoconch marked by a low varix.

Remarks. The present taxon differs from previously described Emarginula species in that it has a smaller, thin shell, a deeper anal slit, and in having a rectangular reticulated teleoconch ornament.

Occurrence. Box-corer samples BC66 (2 specimens), BC70 (1), BC71 (15). Maximum length: 3.5 mm.

Distribution and habitat. Emarginula tenera occurs in eastern Atlantic waters (Lusitanian seamounts) in the 96–485 m bathymetric interval, and in the Mediterranean from 15 to about 600 m depth; it was considered to represent an element of the CB (deep-sea white corals) bathyal biocoenosis, possibly feeding on Porifera ( Poppe & Goto 1991; Bogi & Giusti 1994; Palazzi & Villari 2001; Beck et al. 2006).

Fossil record. None recorded.

Figures

FIGURE 11. a – c: Antalis agilis (Sars M. in Sars G. O., 1872), samples BC 04 (a) and BC 72 (b – c), scale bars: 5 mm (a), 0.2 mm (b, posterior aperture), 1 mm (c, anterior aperture); d – f: Entalina tetragona (Brocchi, 1814), sample BC 72, scale bars: 2 mm (d), 0.1 mm (e, posterior aperture), 0.5 mm (f, anterior aperture); g: Cadulus subfusiformis (Sars M., 1865), sample BC 52, scale bar 0.5 mm; h – k: Propilidium exiguum (Thompson, 1844), sample BC 66, scale bars: 1 mm (h – i), 0.1 mm (j – k, protoconch); l – n: Emarginula adriatica (Costa O. G., 1830), sample BC 72, scale bars: 2 mm (l – m), 0.1 mm (n, protoconch); o – q: Emarginula multistriata Jeffreys, 1882, sample BC 70, scale bars: 1 mm (o – p), 0.1 mm (q, protoconch); r – t: Emarginula tenera Locard, 1982, sample BC 71, scale bars: 1 mm (r – s), 0.1 mm (t, protoconch).