Typhinellus laminatus, Roland & Virginie, 2015

Roland, Houart & Virginie, Héros, 2015, New species of Muricidae Rafinesque, 1815 (Mollusca: Gastropoda) from the Western Indian Ocean, Zoosystema 37 (3), pp. 481-503 : 498

Typhinellus laminatus n. sp.

( Figs 10 A-F; 11B)

TYPE MATERIAL. — Holotype (lv) MNHN-IM-2000-30019 and 1 (dd) paratype MNHN-IM-2000-30020.

TYPE LOCALITY. — Madagascar, off Baie Mahajamba, 14°53’S, 46°56’E, 90-257 m [MIRIKY: stn DW3245].

MATERIAL EXAMINED. — Only known from the type material.

DISTRIBUTION. — North-western Madagascar, taken alive at 90- 257 m.

ETYMOLOGY. — Latin, lamina, thin blade. This species is named for its thin axial lamellae.

DESCRIPTION

Holotype medium sized for the genus, 16.3 mm in height. Height/width ratio 1.7, narrowly-ovate, smooth, delicate. Subsutural ramp moderately broad, weakly sloping, weakly concave.

Light ochre or light tan, brown on subsutural ramp on third, fourth and last teleoconch whorls, light brown spiral band at periphery. A single brown spot at adapical edge of aperture and three on edge of outer apertural lip. Three additional weak, light brown spots on left part of ventral side of siphonal canal.

Spire high with 1.75 protoconch whorls and five weakly convex, angulate, strongly shouldered teleoconch whorls. Suture of whorls impressed. Protoconch small, whorls rounded, slightly eroded. Terminal lip unknown (eroded).

Axial sculpture of teleoconch whorls consisting of four high, thin, sharp lamellate varices, each with a weakly open, short, inward curved shoulder spine. Apertural varix broad, flangelike, dorsally reflected, with two broadly open, short spinelets at outer edge. Variceal flange extending to tip of siphonal canal. Shoulder spine broad, triangular, very weakly dorsally curved, connected to last teleoconch whorl by a broad, high, lamellate partition. Spiral sculpture faint, consisting of P1 with the anal tube, P2 (shoulder spine) and probably P3, P4, P5 and P6 with very faint secondary cords. Spiral sculpture more obvious on adapertural part of apertural varix. P1 with long, tapering, ventrally sealed anal tube, forming an angle of approximately 85-90° with axis of shell, only apertural tube hollow and functional, older tubes broken off and closed. P2 with a weakly open, curved shoulder spine, P4 and P5 corresponding to broad, open spinelets at outer apertural margin. Very thin intritacalx consisting of simple axial striae present.

Aperture small, ovate, forming a continuous peristome. Columellar lip narrow, outer lip smooth within. Siphonal canal long, broad, straight, ventrally sealed. Left side of canal weakly overlapping right side.

Operculum and radula unknown.

REMARKS

Typhinellus laminatus n. sp. differs from Typhinellus bicolor Bozzetti, 2007 ( Fig. 10G, H ) in having a smooth shell with the exception of a few, rather indistinct spiral cords, whereas T. bicolor has a microsculpture of irregular pits, visible even in the worn holotype. Typhinellus laminatus n. sp. also has a more fragile shell, sharper axial varices and a slightly smaller aperture, 17.1% of shell height and 19% of shell width as opposed to 17.6% of shell height and 22.6% of shell width in T. bicolor (measurements made on the holotype of T. laminatus n. sp. and specimens of T. bicolor from ATIMO VATAE, stn BP11).

Typhinellus laminatus n. sp. differs from T. androyensis Bozzetti, 2007 ( Fig. 10K ) in having a more fragile shell with narrower teleoconch whorls, much thinner and sharper axial varices and a flatter siphonal canal.

Typhinellus laminatus n. sp. differs from T. amoenus Houart, 1994 ( Fig. 10I, J ) in the same characters as it differs from T. androyensis but also in having a smooth shell as opposed to the strongly spirally sculptured shell in T. amoenus .

Figures

FIG. 10. — A-F, Typhinellus laminatus n. sp.; MIRIKY, stn DW3245, 90-257 m; A-C, holotype MNHN IM-2000-30019, 16.3 mm; D, E, paratype MNHN IM-2000- 30020, 14.8 mm;F, protoconch; G, H, Typhinellus bicolor Bozzetti, 2007;South Madagascar, Lavanono,holotype MNHN IM-2000-20852, 21.2 mm; I, J Typhinel- lus amoenus (Houart,1994), Umhlanga Rocks, Natal, South Africa, holotype NMSA S436, 21 mm, photo courtesy A. Marais;K, Typhinellus androyensis Bozzetti, 2007;ATIMO VATAE,BB04,14-18 m, 14.9 mm; L-P, Typhinellus constrictus n. sp.: L-N, ATIMO VATAE,BS09,11-13 m, holotype MNHN IM-2009-14446, 15.4 mm; O, P, ATIMO VATAE, stn CP3511, 97-98 m, paratype MNHN IM-2000-30022 20.7 mm. Scale bar: F, 500 µm.