Pazinotus chionodes, Houart & Héros, 2012

Houart, Roland & Héros, Virginie, 2012, New species of Muricidae (Gastropoda) and additional or noteworthy records from the western Pacific, Zoosystema 34 (1), pp. 21-37 : 27-28

Pazinotus chionodes n. sp.

( Fig. 2A, B, M)

TYPE MATERIAL. — Holotype (dd) MNHN 24178 and 1 paratype (dd) MNHN 24179 .

MATERIAL EXAMINED. — Only known from the type material.

TYPE LOCALITY. — Coral Sea, off New Caledonia, S Lansdowne, 20°47’S, 161°01’E, 289-294 m [ EBISCO: stn DW2639, Bouchet, Lozouet, Warén, Richer-IRD coll., 22/X/2005].

DISTRIBUTION. — Known only from the Coral Sea at the type locality.

ETYMOLOGY. — From ancient Greek “chionodes”: snow white.

DESCRIPTION

Shell medium sized for the genus, holotype 10.1 mm in height, height/width ratio 1.41. Broadly-ovate, lightly built. Subsutural ramp weakly sloping on early whorls, more strongly sloping on last whorl, especially between penultimate and last (apertural) varix, weakly convex. Shell entirely white.

Spire high with 1.5 protoconch whorls ( Fig. 2M) and teleoconch of 4.5 broad, convex, strongly shouldered whorls. Protoconch small, whorls rounded, smooth, glossy. Diameter (holotype) 600 µm. Terminal lip delicate, thin, weakly curved.

Axial sculpture of teleoconch whorls consisting of high, narrow, broadly lamellate varices, each with broad, open shoulder spine. Last (apertural) varix shoulder spine broader, long. Preceding varices with narrowly open shoulder spine. Abapical spines long, very broad, connected to each other with narrow, broadly expanded lamellar flange, extending from last varix of preceding whorl to tip of siphonal canal. Last whorl with four varices, early whorls with five. Spiral sculpture of low, very weak, narrow, smooth primary and secondary cords. First teleoconch whorls with visible weakly defined P1 ending as lightly adapically bent shoulder spine. P2 more weakly defined, occasionally with very weak s1 between P1 and P2. Spiral sculpture of last whorl with weak, narrow, low P1-P6 and ADP, MP, ABP. Spiral sculpture occasionally more apparent on abapertural side of lamellate varices. Very weak, quite indiscernible, irregular, secondary cords.

Aperture large, ovate. Columellar lip narrow with three strong knobs abapically. Last abapical knob high and strong. Rim weakly detached abapically. Anal notch shallow, broad. Outer lip erect, smooth, with weak IP and five strong denticles within: D1-D5; D1 strongest, D3-D4 weakest, D2 and D5 of approximately similar strength. Siphonal canal short, broad, dorsally recurved at tip (partially broken in both specimens examined), narrowly open.

Operculum and radula unknown.

REMARKS

There are six known Recent species of Pazinotus in the tropical Indo-West Pacific: P. brevisplendoris ( Houart, 1985) , P. falcatiformis ( Thiele, 1925) , P. kilburni (Houart, 1987) , P. sibogae (Schepman, 1911) , P.smithi (Schepman, 1911) and P. spectabilis Houart, 1991 . None of these is particularly close to P. chionodes n. sp. except P. falcatiformis ( Fig. 2K, L), which differs from P. chionodes n. sp. in having a more triangular outline, a less expanded varical flange, 5 lamellate varices on the last teleoconch whorl, and in having a comparatively narrower aperture.

Pazinotus falcatiformis ( Thiele, 1925) ( Fig. 2K, L)

Murex falcatiformis Thiele, 1925: 168 , pl. 18, fig. 10.

TYPE MATERIAL. — Holotype dd, ZMB.

NEW MATERIAL EXAMINED (all MNHN). — Solomon Islands (new record). SALOMON 2: stn DW2234, Choiseul Island, Oldham Deep, 6°51’S, 156°24’E, 182-277 m, 1 dd. — SALOMONBOA 3: stn CP2809, E Malaita, 9°19’S, 161°27’E, 788-1042 m, 1 dd ( Fig. 2K, L).

T YPE LOCALITY. — North of Nias Island, Sumatra, Indonesia, 1°48’N, 97°6’E, 141 m.

DISTRIBUTION. — Indonesia, Philippines (Houart 2008), Fiji ( Houart & Héros 2008) and Solomon Islands, living in 290-300 m ( Houart & Héros 2008), shells in 141- 788 m.

REMARKS

Pazinotus falcatiformis was described from Indonesia. Other specimens are known from Aliguay Islands, Sulu Sea, Philippines (Houart 2008), Fiji ( Houart & Héros 2008) and now the Solomon Islands. The holotype is larger but with more numerous teleoconch whorls, it also has longer, more acute shoulder spines than in other examined material, but other shell characters (paucispiral protoconch, angulate aperture, spines connected by a broad webbing, number of varices, ontogeny and morphology of the spiral cords) are similar to those of specimens from the other localities.