Vokesimurex aliquantulus, 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 : 484

Vokesimurex aliquantulus n. sp.

( Figs 3M, N ; 4 A-E; 5B)

TYPE MATERIAL. — Holotype (lv), MNHN-IM-2007-36971 BOLD ID BOMGA020-15, GenBank accession number KP697992 for COI gene KC860506 and 5 paratypes (lv) MNHN: 3 MNHN-IM-2000-30002, 1 MNHN-IM-2007-36950, 1 MNHN-IM-2007-36958 BOLD ID BOMGA021-15, GenBank accession number KP697993 for COI gene KC860506 ; 1 paratype coll. RH (all from type locality).

TYPE LOCALITY. — Madagascar, between Nosy Be and Banc du Leven, 12°39’S, 48°22’E, 70-74 m [MIRIKY: stn CP3206].

MATERIAL EXAMINED. — Known only from the type material.

DISTRIBUTION. — Northern Madagascar, taken alive at 70- 74 m.

ETYMOLOGY. — Latin, aliquantulus , little, small. This species is named for its small size relative to the other Murex s.s. species.

DESCRIPTION

Shell small for the genus, up to 33.1 mm in height. Height/ width ratio 2.3 (holotype). Slender, lanceolate, narrowlyovate, nodose, lightly built. Shoulder ramp strongly sloping, weakly convex.

White with occasionally a very light brown darker band on P1 and P2, more obvious on P2 and on axial varices, and between P6 and P7. Aperture white.

Spire high with 1.75-2.00 protoconch whorls and teleoconch up to 6.25, convex, narrow, weakly shouldered, nodose whorls. Suture impressed. Protoconch small, whorls rounded, smooth, occasionally with a narrow keel abapically, width 700 µm. Terminal lip heavy, broad, erect, weakly curved.

Axial sculpture of teleoconch whorls consisting of low, narrow, rounded ribs and high, rounded, weakly spinose varices. First whorl with 11 or 12 ribs, second with 11-13, third with 10-12, early varices on fourth whorl with two or three intervariceal ribs. Last whorl with three high, narrow, rounded varices and two broad intervariceal ribs, occasionally with a third narrow one. Spiral sculpture of moderately high, narrow, weakly nodose primary, secondary and tertiary cords. First whorl with P1-P4, P4 partially covered by the following teleoconch whorl, second and third whorls with IP, P1-P4, fourth with adis, IP, P1, P2, P2, P3, s3, P4, fifth with adis, IP, abis, P1, P2, P3, s3, P4, sixth and seventh with t, adis, (t), IP, abis, P1, s1, P2, s2, P3, s3, P4, s4, P5, s5, P6, s6, P7, s7, ADP, ads, MP, ms, ADP, ads. Other spiral cords decreasing in strength and height abapically. Intersection of axial varices and P1 giving rise to a short, narrow, narrowly open, acute shoulder spinelet from fourth or fifth to last teleoconch whorl.

Aperture narrow, roundly-ovate. Columellar lip narrow, strongly flaring with two or three elongate, weak knobs abapically. Rim erect, a small portion adherent adapically. Low parietal tooth at extreme adapical extremity. Anal notch shallow, broad. Outer lip strongly erect, weakly crenulated, bearing eight weak, elongate, narrow denticles within: ID, D1-D7. Siphonal canal narrow, straight, weakly dorsally recurved, weakly open, occasionally with a single, acute, short spine adapically.

Operculum and radula not examined.

REMARKS

Vokesimurex aliquantulus n. sp. differs from V. gallinago fernandesi ( Fig. 3H, I ) in being more lightly-built, in having a narrower and more acute spire, a narrower siphonal canal and a comparatively narrower aperture. The protoconch is also much smaller, 700 µm wide × 750 µm high as opposed to 1000-1200 µm wide × 1000-1100 µm high. It also has a very narrow spiral keel abapically, not observed in V. gallinago fernandesi .

Vokesimurex aliquantulus n. sp. differs from Vokesimurex rectaspira n. sp. ( Fig. 3 A-G) in the same characters and in having a spire that is weakly incurved and not almost straight as in Vokesimurex aliquantulus n. sp.

It differs from Vokesimurex gallinago gallinago (Sowerby III, 1903) and V. dentifer (Watson, 1883) , not present in the western Indian Ocean, in also having a smaller protoconch (700 µm wide vs 1100-1200), a narrower aperture and a narrower siphonal canal. From V. gallinago gallinago it also differs in having almost spineless varices, rather than the more spinose, occasionally weakly webbed varices of V. gallinago gallinago .

Vokesimurex rectirostris (Sowerby II, 1841) ( Fig. 4F, G ) and V. sobrinus (A. Adams, 1863) ( Fig. 4H, I ) both have a rounded protoconch with a strong keel abapically but in V. aliquantulus n. sp. the keel is more delicate, narrower and situated more abapically, and the protoconch is also relatively smaller (700 vs 1100-1400 µm wide). Both these species, restricted to the region from Taiwan to southern Japan, are also more spinose.

Figures

FIG. 3. — A-G, Vokesimurex rectaspira n. sp.; ATIMO VATAE: stn CP3589; A, B, holotype MNHN IM-2009-14495, 41.2 mm; C, D, paratype MNHN IM-2000- 30001, 38.2 mm; E, F, paratype MNHN IM-2000-30001, 24.8 mm; G, protoconch; H, I, Vokesimurex gallinago fernandesi (Houart, 1990); Mozambique, 93-112 m, holotype MNHN IM-2000-0089, 63.2 mm; J-L, Vokesimurex dolichourus (Ponder & Vokes, 1988); J, K, MIRIKY, stn CP3288, 46-54 m, 56.2 mm; L, protoconch; M, N, Vokesimurex aliquantulus n. sp.; MIRIKY, stn CP3206, 70-74 m, holotype MNHN IM-2007-36971, 28.3 mm. Scale bars: G, L, 500 µm.

FIG. 4. — A-E, Vokesimurex aliquantulus n. sp., MIRIKY, stn CP3206, 70-74 m; A, B, paratype MNHN IM-2000-30002, 33.1 mm; C, D, paratype MNHN IM-2000- 30002, 22.6 mm;E, protoconch;F, G, Vokesimurex rectirostris (Sowerby,1881), Taiwan Strait,Coll.RH,68 mm;H, I, Vokesimurex sobrinus (A.Adams,1863);Tosa, Japan, Coll. RH, 51.3 mm; J-O, Timbellus pannuceus n. sp.; J, K, MIRIKY, stn CP3184, 492-524 m, holotype MNHN IM-2007-36940, 18.9 mm; L, M, paratype MNHN IM-2007-38031, 20.6 mm; N, detail of the aperture; O, protoconch; P, Q, Timbellus fulgens (Houart, 1988); MIRIKY, stn DW3215, 316-433 m, 22.5 mm. Abbreviations: See Material and methods. Scale bars: E, O, 500 µm.