Timbellus goniodes, 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 : 488

Timbellus goniodes n. sp.

( Figs 6 C-G; 7B)

TYPE MATERIAL. — Holotype (dd) MNHN-IM-2000-30006, 3 paratypes MNHN, 1 paratype coll. RH (as listed below).

TYPE LOCALITY. — South Madagascar, South of Cap Sainte-Marie, 26°14’S, 45°09’E, 284-286 m [ATIMO VATAE: stn CP3615].

MATERIAL EXAMINED. — South Madagascar. ATIMO VATAE: stn DW3552, South of Faux-Cap, 26°07’S, 45°39’E, 264-280 m, 2 dd (1 paratype MNHN-IM-2000-30007, 1 Coll. RH). — Stn DW3553, South of Faux-Cap, 26°08’S, 45°39’E, 280-333 m, 1 dd fragment (paratype MNHN-IM-2000 30008). — Stn CP3615, South of Cap Sainte-Marie, 26°14’S, 45°09’E, 284-286 m, 2 dd (holotype MNHN-IM-2000-30006, 1 paratype MNHN-IM-2000-30009).

DISTRIBUTION. — Southern Madagascar, 280-284 m (shells only).

ETYMOLOGY. — Greek, goniodes , angular. This species is named for the angular shape of the teleoconch whorls.

DESCRIPTION

Shell medium sized for the genus, up to 23.7 mm in height at maturity. Height/width ratio 1.6-2.0. Slender, narrowlyovate, spinose, lightly built. Shoulder strongly sloping, weakly concave or straight.

Milky white or pinkish white. Aperture white.

Spire high, acute, with 1.5 protoconch whorls and teleoconch up to six weakly convex, angular, weakly shouldered whorls. Suture impressed. Protoconch small, whorls rounded, smooth, glossy, width 600-650 µm.Terminal lip delicate, thin, weakly raised, weakly curved.

Axial sculpture of teleoconch whorls consisting of high, narrow, lamellose varices, each with a long, narrow, open shoulder spine. First whorl with six or seven varices, second with five or six, third with four. From fourth to last teleoconch whorl, three narrow, high, lamellose, webbed varices. Spiral sculpture of low and high, narrow, rounded primary cords. First whorl with P1-P3 of approximately the same strength, second with P1-P3, P2 becoming broader and higher. Third and fourth whorls with shallow, almost obsolete P1, P2 and P3 similar in strength and height, P3 partially covered by following whorl, fifth whorl with very shallow P1 and broad, high, rounded P2 and P3, last whorl with weak P1, more obvious on lamellose, webbed varices, P2 and P3 higher and broader, P4-P6 weak, decreasing in strength abapically, broader on webbed apertural varix. P1 ending as a short, narrow, adapically bent shoulder spine. P2-P6 ending as a shorter, backward recurved, narrowly open spine.

Aperture ovate, angular. Columellar lip narrow, flaring, smooth or with two weak knobs abapically, rim partially erect, adherent at adapical extremity. Anal notch moderately deep, broad. Outer lip strongly erect, smooth with six weak or strong denticles within: ID, D1-D5. ID very low, broad, D1-D5 variable in strength and height. Siphonal canal moderately short, broad, weakly abaxially bent and dorsally recurved at tip, narrowly open, with variceal webbing extending to 80- 90% of its length.

Operculum and radula unknown.

REMARKS

Timbellus goniodes n. sp. differs in many ways from the other Indo-West Pacific Timbellus species. From T. fulgens ( Fig. 4P, Q ) living in the same geographical area, T. goniodes n. sp. differs in having a narrower shell with a higher spire, a smaller protoconch (600-650 µm wide vs 1000 µm), a narrower subsutural ramp, strong and relatively broader spiral cords with higher P2 and P3, a more angular aperture and more strongly adapically bent shoulder spines, and chiefly in having four to seven varices on the three adapical teleoconch whorls as opposed to three in T. fulgens .

From T. crauroptera ( Fig. 6H ) from New Caledonia, a species that also has upward bent shoulder spines and a more angular aperture, T. goniodes n. sp. differs in having somewhat narrower shoulder spines, more strongly obvious spiral cords, less convex teleoconch whorls without intervariceal varices, a higher spire and variceal webbing extending to almost 80% of the length of the siphonal canal rather than extending to 10 or 20% of its length in T. crauroptera with the additional presence of ADP and MP. Moreover T. crauroptera also has three variceal wings starting at the first teleoconch whorl.

Figures

FIG. 6. — A, B, Timbellus vespertilio (Kuroda, 1959), East China Sea, Coll. RH, 28 mm; C-G, Timbellus goniodes n. sp., C, D, ATIMO VATAE, stn CP3615, 284- 286 m, holotype MNHN IM-2000-30006, 23.7 mm; E, F, ATIMO VATAE, stn DW3552, 264-280 m, paratype MNHN IM-2000-30007, 14.8 mm; G, protoconch; H, Timbellus crauroptera (Houart, 1991); New Caledonia, BIOCAL, stn DW64, 250 m, holotype MNHN IM-2000-0132, 11.4 mm; I-M, Bouchetia wareni n. sp., Madagascar,MIRIKY,stn CP3189,346-376 m; I, J, holotype MNHN-2007-36941, 18.1 mm;K, L, MIRIKY,stn CP3183,paratype MNHN IM-2007-36941, 12.8 mm; M, protoconch; N, O, Bouchetia vaubanensis Houart,1986;South of New Caledonia,VAUBAN 1976-1978, stn DR01,480-500 m, holotype MNHN IM-2000-0885, 10.5 mm; P, Q, Flexopteron akainakares n. sp., ATIMO VATAE, stn DW3524, 307-319 m, holotype MNHN IM-2000-30012, 12.2 mm. Scale bars: G, M, 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.