Triforis (Mastonia) monacha Hervier, 1898

Albano, Paolo G., Franco, Davide Di, Azzarone, Michele, J., Piet A., Bakker & Sabelli, Bruno, 2023, Review of the types of Indo-Pacific Triphoridae (Mollusca, Gastropoda) in the Muséum national d’Histoire naturelle, Paris, Zoosystema 45 (2), pp. 13-106 : 46-48

Triforis (Mastonia) monacha Hervier, 1898 ( Fig. 26 )

Triforis (Mastonia) monacha Hervier, 1898: 257 , illustrated by Hervier (1899: pl. 16, fig. 7).

TYPE LOCALITY. — Lifou, New Caledonia.

TYPE MATERIAL. — Syntype. New Caledonia • MNHN-IM-2000-1503; 2 specimens; from type locality.

ORIGINAL DESCRIPTION. — T. sinistrorsa , elongata , circa medium tumida, latere convexa, apice acuminata, solida, castaneo-brunnea, gemmis olivaceo seu luteo-lividis decorata. Anfractus 13-15; embryonales 3 carinati, striatuli, pallidè corneo-lutei; subsequentes 2 biseriatim granulosi, violaceo-albi; inferiores sutura undulata, crassiuscula, indistinctè discreti, longitudinaliter costulati et triseriatim gemmati, in interstitiis transversim densè et minuté striati. Costulae in sulcis transversis vix distinctae. Lirae gemmiferae, elevatae, subaequaliter distantes. Gemmae sphaericae, in prima et in tertia serie fortiores, intermediae minores in anfr. superioribus, in 3-4 inferioribus anfr. subaequales. Ultimus anfractus convexus, 5 liris gemmiferis (prioribus 4 aequalibus) cinctus, circa basalem canalem depressus. Canalis basalis brevis, unicarinatus, ferè clausus, recurvus. Apertura obliquè piriformis, intùs brunnea. Columella arcuata, valdè obliqua. Labrum arcuatum, prominens, infernè columellae quasi junctum, supernè infra suturam breviter et rotundè fissuratum.— Long. 6-7 mill.; diam. max. 2.50 mill. Hab. Insula Lifou. Vidi 10 specimina, à H. P. Goubin, S. M., collecta.

TRANSLATION OF THE LATIN TEXT. — Sinistral shell, elongated, broad near the centre, laterally convex, acute apex, solid, brownish, adorned by olivaceous or dark-yellow tubercles. From 13 to 15 whorls; embryonic whorls are three, carinated, striated, light brownyellow; subsequent two whorls have two granulated spiral cords and are coloured in purplish-white; inferior whorls are separated by a wavy, slightly thick and indistinct suture, costulate longitudinally and with three tubercled spiral cords, transverse interspaces are densely and minutely striated. Ribs are barely distinct inside the cord interspaces. Spiral cords are tubercled, elevated, slightly equally spaced. Gemmae are spherical, stronger on the first and third series of spiral cords, in the superior whorls the intermediate tubercles are smaller, in the three-four inferior whorls they are slightly equal. Convex last whorl, with five tubercled spiral cords (first four cords are equal), depressed near the siphon. Short siphon, unicarinated, almost closed, curved. Obliquely pyriform aperture, internally brown. Arched columella, strongly oblique. Arched lip, protruding, below almost attached to the columella, above shortly and roundly fissured under the suture. — Length 6-7 mm; maximum diameter 2.50 mm. Locality: Lifou Island. I saw 10 specimens collected by R. P. Goubin.

DIAGNOSIS. — Shell cyrtoconoid. Both syntypes 5.2 mm high. Teleoconch of c. 9 whorls. Three spiral cords present, the second appearing on the fifth whorl. First and third cords with tubercles at the intersection with slightly prosocline axial ribs. Second cord initially with thin tubercles, becoming larger on the lower whorls. Spiral microsculpture of fine threads between the spiral cords. Peristome with additional cords below the second and third spiral cord. Posterior sinus shallow. Base with three additional tubercled cords. Teleoconch brown, with slightly darker interspaces between the spiral cords. Protoconch missing in the syntypes.

Figures

FIG. 26. — Triforis (Mastonia) monacha Hervier, 1898, Lifou,New Caledonia: A, original figure in Hervier (1898); B-I, syntype 1, MNHN-IM-2000-1503; front (B, C), side (D, E), back (F), peristome (G, H), microsculpture (I); J, N, original labels; K-M, syntype 2, MNHN-IM-2000-1503; front (K), side (L), back (M). Scale bars: B-F, K-M, 1 mm; G, H, 0.4 mm; I, 0.2 mm.