Triforis (Mastonia) mediotincta Hervier 1898

Triforis (Mastonia) mediotincta Hervier, 1898 (Fig. 24)

Triforis (Mastonia) mediotincta Hervier, 1898: 259, illustrated by Hervier (1899: pl. 17, fig. 3).

TYPE LOCALITY. — Lifou, New Caledonia.

TYPE MATERIAL. — Syntype. New Caledonia • MNHN-IM-2000-1490; 1 specimen; from type locality.

ORIGINAL DESCRIPTION. — T. sinistrorsa, parvula, ovato-elongatula, obesula, latere convexa, apice acuminata, solida, alba, versùs medium luteo copiosè maculata. Anfractus circa 12 (?), sutura lineari, undulata, vix distincta discreti, longitudinaliter costulati (costulis rotundoplanatis, laevigatis), transversim liris gemmiferis biseriatim decorati, lirula intermedia, minore in ultimis 3 anfractibus, muniti. Lirarum intervalla suturae sulcis latiora. Ultimus anfractus convexo-rectiusculus, 6 liris gemmiferis ornatus. Canalis basalis brevis, valdè recurvus, quasi clausus. Apertura parvula, piriformis. Columella concava, latere erecta; labrum tenue, semi-circulare, supernè fissuratum. — Long. 3 mill.; diam. max. 1.50 mill.

Hab. Insula Lifou. Vidi 4 specimina, à R. P. Goubin, S. M., collecta.

TRANSLATION OF THE LATIN TEXT. — Sinistral shell, small, ovate and elongated, broad, laterally convex, acute apex, solid, white, towards the centre abundantly spotted with yellow. Whorls about 12 (?), separated by a linear, waved and barely distinct suture, longitudinally costulate (ribs are rounded-flattened, smooth), adorned by two series of tubercled spiral cords and with an intermediate spiral cord which is smaller in the last three whorls. The interspace of the spiral cords is wider than the suture. Last whorl quite straightconvex, adorned by six tubercled spiral cords. Short siphon, strongly curved, partly closed. Small aperture, pyriform. Concave columella, laterally straight; thin lip, semi-circular, fissured above. — Length 3 mm; maximum diameter 1.50 mm.

Locality: Lifou Island. I saw 4 specimens collected by R. P. Goubin.

DIAGNOSIS. — Shell cyrtoconoid. Syntype 2.7 mm high.Teleoconch of 7 whorls. Three spiral cords present, the second appearing on the fifth whorl. First cord more prominent. First and third cords with tubercles at the intersection with rather prosocline axial ribs. Second cord initially as a fine thread, but then developing thin tubercles. Spiral microsculpture of barely visible fine threads. Peristome with additional cords below the second and third cord. Posterior sinus shallow. Base with three additional tubercled cords. Protoconch largely missing in the syntype but possibly multispiral. Teleoconch white with large brown blotches on the fifth to the seventh whorls. Protoconch brown.