Mipus boucheti, Oliverio, 2008

Oliverio, Marco, 2008, Coralliophilinae (Neogastropoda: Muricidae) from the southwest Pacific, Mémoires du Muséum national d'Histoire naturelle 196, pp. 481-586 : 561-562

Mipus boucheti n. sp.

Figs 129, 130, 132, 198-205

TYPE MATERIAL. — Holotype (lv) MNHN 20239 and 1 paratype (lv) MNHN 20240 .

TYPE LOCALITY. — Vanuatu, 17°53’S, 168°25’E, 300-301 m [MUSORSTOM 8: stn CP 1018] .

MATERIAL EXAMINED. — Vanuatu. MUSORSTOM 8: stn DW (holotype MNHN 20239 ) associated with Flabellum pavoninum 1016 , 17°53’S, 168°28’E, 291-300 m, 1 lv (paratype MNHN Lesson, 1831 (coalitum form, Fig. 132, S. Cairns det.).

20240); stn CP 1018, 17°53’S, 168°25’E, 300-301 m, 1 lv

DISTRIBUTION. — Known only from the type locality ( Vanuatu), live in 300 m.

DESCRIPTION. — Shell small for the genus, holotype 13 mm high, 10 mm wide, biconical, of moderate thickness. Colour orange-pinkish.

Protoconch of 1.8 globose whorls, 780 µm high and 700 µm wide at base. Sculpture of pustules over entire surface; after 0.8 whorls, 2 weakly developed spiral keels appearing, with a series of collabral riblets.

Teleoconch of 4 conical whorls. Spire moderately high, with flat outlines, suture not incised, periphery angled and keeled, base constricted. Aperture large, circular; outer lip simple, thin, inner lip thin. Siphonal canal relatively long, narrowly open. Umbilicus widely open, fasciole imbricate.

Axial sculpture of strongly prosocline growth lines. Spiral sculpture of faint threads above the peripheral keel, and of 14 closely set, slightly scaly cords below. Peripheral keel consisting of a cord, suprasutural in first whorls, nodulose due to reduced scaly spines, starting immediately after the protoconch-teleoconch boundary, along with 2 subsutural cordlets. Cordlets vanishing over the first teleoconch whorl, leaving only faint threads on subsutural ramp.

Animal white. Operculum thin, yellow, ovate-circular.

REMARKS. — Mipus boucheti is similar to M. eugeniae , but its very reduced spiral sculpture distinguishes the two species easily. The reduced spiral sculpture also distinguishes the new species from the sculptured Mipus isosceles .

The specimen from stn CP 1018 was collected associated with a solitary Flabellum pavoninum , one of the four fabellid corals recorded at stn 1018 by Cairns (1999). The single capsule in the mantle cavity contained 27 young larvae of 1.3 whorls, 1.1 mm long. The change in protoconch sculpture after a distinct demarcation at 0.8 whorls could be taken as an indication of planktotrophic development. However, their presence at a size of 1.3 whorls in the capsule and the non-sinusigeral protoconch-teleoconch boundary indicate a prolonged intracapsular development. Note that a demarcation between protoconch-I and protoconch-II can occur in non-planktotrophic species.

ETYMOLOGY. — Dedicated to Philippe Bouchet, in honour of his enthusiastic work to enhance our knowledge of the marine biodiversity of the southwest Pacific.