Triphoris angasi Crosse & Fischer, 1865

Albano, Paolo G., Bakker, Piet A. J. & Sabelli, Bruno, 2019, Annotated catalogue of the types of Triphoridae (Mollusca, Gastropoda) in the Natural History Museum of the United Kingdom, London, Zoosystematics and Evolution 95 (1), pp. 161-308 : 161

Triphoris angasi Crosse & Fischer, 1865

Figure 15

Triphoris angasi Crosse and Fischer 1865: 46, pl. 1, figs 12, 13.

Type locality.

"St. Vincent" [Gulf St Vincent, South Australia].

Type material.

Syntypes: NHMUK 1870.10.26.127, 1 specimen, St. Vincent Gulf, South Australia (coll. G.F. Angas) .

Original description.

T. imperforata, sinistrorsa, conico-turrita, subelongata, tenuiuscula, brunnea; apice acuminato; sutura linearis, fere inconspicua; anfr. 15 planiusculi, embryonales 3 laeves, sequentes cingulis 3 granulorum (intermedio paulo minore) spiraliter impressi, ultimus quadricingulatus, transversim zona alba ornatus, basi brunneo-violacea; apertura oblique subquadrato-piriformis, intus brunneo lirata, margine columellari arcuato, externo flexuoso, in vicinio columellae ligulatim ascendente; canali brevi tubuliformi. - Long. 7 millim., diam. maj. 1 millim. 7/19.

Hab. in sinu “Saint-Vincent” dicto (coll. Angas).

Coquille imperforée, sénestre, de forme conico-turriculée, suballongée, assez mince et de couleur brune; le sommet est acuminé, la suture linéaire et Presque imperceptible. Les tours, au nombre de 15, sont aplatis; les trois premiers sont lisses, les suivants sont ornés transversalement de trois cercles de granulations assez grosses; celui du milieu est un peu plus petit que les autres, et tend même à disparaître dans les tours supérieurs; le dernier tour porte quatre cingulations au lieu de trois, et est orné d’une zone blanche transverse; sa partie basale est d’un brun violâtre. L’ouverture, située un peu obliquement, est plutôt piriforme que quadrangulaire, et marquée de quelques lignes brunes à l’intérieur. Le bord columellaire est arqué, le bord externe est flexueux et vient s’appliquer, en forme de languette, le long de la columelle. Le canal est court et tubuliforme. - La longueur totale de la coquille est de 7 millimètres, son plus grand diameter de 1 7/10.

Cette espèce provident du golfe de Saint-Vincent. Le T. hindsi, Deshayes (1), est, à notre connaissance, la forme qui s’en rapproche le plus sous le rapport du système de sculpture; mais les granulations sont proportionnellement plus grosses dans le T. angasi, qui compte, d’ailleurs, trois tours de spire de plus, et qui se distingue par son ouverture plus large et par la zone blanche de son dernier tour. Nous dédions cette espèce à M. French Angas.

Translation of the Latin text.

Sinistral imperforated shell, turreted-conical, subelongated, rather slender, brown; sharp apex; linear suture more or less inconspicuous; 15 rather flat whorls, three light embryonic, subsequent with three spiral rows of granules (smaller intermediate), four on the last with a white spiral band, base violet-brown; subsquared, pyriform slanting aperture with brown lines inside, arched columellar edge, bending external lip ascending like a strip near the columella; short, tubular anterior siphon. Length 7 mm, major diameter 1 7/ 19 mm.

Habitat. In the gulf known as "St. Vincent" (coll. Angas).

Diagnosis.

Syntype 5.9 mm. Shell conical, with flat sides. Teleoconch of 11 whorls, with three spiral cords with tubercles at the intersection with opisthocline axial ribs. The second cord appears on the fifth whorl as a fine thread and becomes fully grown at mid-shell height. A fourth poorly sculptured cord is sometimes visible suprasuturally. Fine growth striae are visible, especially in the interspaces of cords and ribs. The peristome has a shallow posterior sinus and no additional cords. The siphonal canal is short. The base has two additional almost smooth spiral cords. The protoconch is multispiral, but the upper whorls are missing in the lectotype, impeding the quantification of the number of whorls. The lower three whorls have two spiral keels and axial riblets. Teleoconch brown with lighter tubercles, fourth spiral cord on the last whorl white, base deep brown, apex likely white (although worn in the lectotype).

Remarks.

This specimen may not be the one on which Crosse and Fischer based their original description, because it is smaller in size (5.9 vs 7 mm) and with fewer whorls (11 vs 15). However, it matches very well the original description and figure; the label (Fig. 15L ) specifies that this is a “type”, from the type locality and collected by G.F. Angas (Crosse and Fischer specified that the new species was based on Angas’ material). Therefore, we consider this specimen as belonging to the type series.

Figures

Figure 15. Triphoris angasi Crosse & Fischer, 1865, Gulf St Vincent, South Australia, coll. G. F. Angas. A-J, L Syntype NHMUK 1870.10.26.127: front (A, B), side (C, D), back (E), protoconch (F, I), peristome (G, J), aperture (H), original labels (L). K Original figures. Scale bars: A-E: 1 mm; F, I: 0.2 mm; G, H, J: 0.5 mm.