Acanthodaphne boucheti, Morassi & Bonfitto, 2010

Morassi, M. & Bonfitto, A., 2010, New raphitomine gastropods (Gastropoda: Conidae: Raphitominae) from the South-West Pacific, Zootaxa 2526, pp. 54-68 : 63-65

Acanthodaphne boucheti new species

Figures 3. A–H

Type material: Holotype MNHN 22308 . Paratypes: 1 MNHN 22309 , 1 MZB 45715, 1 ZRC 2980.

Type locality: Solomon Islands, 08°19.4’S 160°38.7’E, 194–286 m [N/ O Alis, SALOMON 1, stn. DW 1770] .

Material examined: only known from the type material.

Description: Shell biconic (b/l 0.39–0.44; a/l 0.40–0.44). Teleoconch consisting of up to 6.5 whorls which are strongly shouldered near middle on early two whorls, above middle on subsequent ones. Last whorl shallowly excavated with a short neck. Whorls separated by a weakly impressed suture margined by a prominent subsutural fold. Sutural ramp relatively narrow, strongly concave. Axial sculpture consisting of prominent opisthocline ribs of rounded triangular cross-section, extending from lower suture to shoulder angle, where they are abruptly truncated and form tubercles. Axial ribs rapidly fading over upper part of base on last whorl. There are 13–14 axial ribs on penultimate whorl, 17–19 on last whorl. Subsutural fold bearing a row of tubercles corresponding in number to axial ribs; in the holotype, which is the largest specimen, the tubercles becomes more numerous than axial ribs (about one and a half their number) on last two whorls.

Sutural ramp sculptured by fine collabral threads sinuous in conformity with the anal sinus. Spiral sculpture consisting of low, flattened cords and threads. First whorl with a moderately prominent peripheral cord joined on subsequent whorl by a second cord anteriorly. Later two whorls with 3–4 primary cords; 1–2 secondary cords or threads occur in the interstices between main cords. Base sculptured by 9–11 widely spaced primary and secondary cords and 6–8 fine threads on the neck. Under SEM magnification, spiral cords are smooth, but their interstices and sutural ramp are covered by dense rows of granules. Aperture broad, oval. Columella nearly straight. Siphonal canal broadly open, poorly differentiated from aperture. Labial callus relatively thick over columella, wide, sculptured by microscopic rows of prickly nodules in its interior part (fig. 3F). Outer lip thin with a moderately deep, reversed L-shaped anal sinus; its deepest point below middle of sutural ramp. Protoconch conical of 3+ whorls; protoconch I missing, protoconch II sculptured by opisthocyrt axial riblets extending from suture to suture decussate by oblique threads on lower third of each whorl. Teleoconch white, protoconch yellowish-beige.

Dimensions: Holotype 12.2 x 4.8 mm, aperture height 4.9 mm; largest paratype: 7.9 x 3.5 mm, aperture height 3.5 mm. Smallest paratype measures 7.4 mm in height and has a broken outer lip; smallest undamaged paratype: 7.7 x 3.4 mm, aperture height 3.3 mm.

Remarks: Acanthodaphne boucheti is larger than any other described Acanthodaphne species. It further differs from A. sabellii in its higher spire, higher shoulder angulation on the teleoconch whorls (figs 3C–D), more numerous spiral cords and more numerous axial ribs (17–19 vs 14–16 on last whorl), which are markedly weaker on the last whorl. Furthermore, in Acanthodaphne boucheti the tubercles on the subsutural fold are relatively large and as numerous as the ribs or one and a half times their number (in the holotype), rather than twice their number as in A. sabellii . In this feature A. boucheti resembles Pseudoinquisitor ? cf P.? pulchra ( Schepman, 1913) figured by MacNeil (1960) but otherwise differential characters are the same as for A. sabellii .

Etymology: This species is named after Philippe Bouchet of the MNHN in recognition of his substantial contributions to Malacology and for his generosity in making the material used for this paper available to us.