Triforis (Mastonia) amoena 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 : 30

Triforis (Mastonia) amoena Hervier, 1898

( Fig. 12 )

Triforis (Mastonia) amoena Hervier, 1898: 264-265 , illustrated by Hervier (1899: pl. 17, fig. 11).

TYPE LOCALITY. — Lifou, New Caledonia.

TYPE MATERIAL. — Syntype. New Caledonia • MNHN-IM-2000-1104; 1 specimen; from type locality .

ORIGINAL DESCRIPTION. — T. sinistrorsa , minuta, ovata, obesa, apice acuminata, vix solidula, nitida, alba, flavo parcè maculata, ad suturas interruptè fulvo tincta. Anfractus 11-12; embryonales 4 carinati, striatuli, luteo-cornei; intermedii convexi, sutura undulata, subcanaliculata discreti, longitudinaliter costulati (costulis laevigatis, rotundis, utrinque ad suturas gemmatis), transversim bilirati, liris subplanatis, prima minore. Gemmae nitidae, subrotundae, subdistantes, inaequales, in secunda serie majores; interstitia laevigata, costulis clathrata, liras inferiores aequantia. Ultimus anfractus convexus, lentè ad basin vix attenuatus, liris 5 graniferis ornatus (prima majore, caeteris minoribus, decrescentibus). Canalis brevissimus, unicarinatus, semiclausus, obliquè recurvus. Apertura rectè subpiriformis, lateraliter compressa et supra fissurata. Peristoma continuum; columella angulata, oblique sub anfractu penultimo latè planata, lateraliter brevissima. Labrum ad ortum canalis columellae junctum, infrà rotundè prodiens, latere planatum, ad suturam sinu parvulo munitum. — Long. 2.50-3 mill.; diam. max. 1.25-1.50 mill.

Hab. Insula lifou. Vidi 8 specimina, à R. P. Goubin, S. M., collecta.

TRANSLATION OF THE LATIN TEXT. — Sinistral shell, ovate, broad, acute apex, barely solid, bright, white, moderately maculated with brown spots and coloured in brown where the suture ends. Eleven to twelve whorls; four embryonic whorls, keeled, striated, yellow-brownish; intermediated whorls are convex, separated by an undulated and moderately channelled suture, longitudinally costulate (ribs are smooth, rounded, with tubercles on both sides of the suture), with two flattened spiral cords, the first of which is smaller. Tubercles are bright, slightly rounded, slightly spaced, unequal, the second series is bigger. Interspaces are smooth, sculptured with ribs, the inferior cords are similar. Last whorl is convex, slowly and barely attenuated at the base, adorned by five spiral cords with granules (the first cord is the biggest one, others are smaller). Very short siphon, with a single keel, halfclosed, curved obliquely. Distinctly pyriform aperture, laterally compressed and fissured above. Continuous peristome; angled columella, oblique under the penultimate whorl and largely flattened, laterally very short. The lip is joined to the beginning of the siphon, roundly protruding below, laterally flattened, with a small sinus at the suture. — Length 2.50-3 mm; maximum diameter 1.25-1.50 mm.

Locality: Lifou Island. I saw 8 specimens collected by R. P. Goubin.

DIAGNOSIS. — Shell cyrtoconoid, rather broad with flat whorls. Syntype 2.5 mm high.Teleoconch of 6 whorls. Three spiral cords present, second cord appearing only on the last whorl. Spiral cords with tubercles at the intersections with rather orthocline axial ribs. Peristome without additional cords, but with vertically elongated tubercles. Posterior sinus relatively shallow. Base with two additional cords with flat tubercles. Protoconch multispiral; in the syntype only the last whorl present bearing axial riblets and apparently two spiral keels. First teleoconch whorl white, the other whorls with yellow to brown blotches on a white background. Brown blotches with always a darker brown line at the suture. Protoconch light brown.

Figures

FIG. 12. — Triforis (Mastonia) amoena Hervier,1898,Lifou, New Caledonia:A, original figure in Hervier (1898); B, C, F-M, syntype, MNHN-IM-2000-1104; front (B, C), side (F, G), back (H), peristome (I, J), apex (K, L), microsculpture (M); D, E, original labels. Scale bars: B, C, F-J, 0.4 mm; K-M, 0.1 mm.