Triphora incolumis Melvill, 1918

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

Triphora incolumis Melvill, 1918

Figure 68

Triphora incolumis Melvill 1918: 149, pl. 4, fig. 18.

Type locality.

Persian Gulf: Fao Cable (Fao was a small village at the confluence of Tigris and Euphrates).

Type material.

Syntypes: NHMUK 1921.1.28.18-20, 3 specimens, Persian Gulf. Syntypes: NMW 1955.158.207, 13 specimens, Persian Gulf (fide Trew 1987; not seen) .

Original description.

T. testa cylindrico-fusiformi, pallide straminea, solidula; anfractibus 16-17, quorum apicales 5 pulchre et minute longitudinaliter striati, paullum decussati, apice ipso laevi, deplanato, caeteris ad suturas profunde impressis, lateribus paullulum convexis, quatuor supernis bi-, his proximis triseriatis, ordinibus nodulato-gemmatis decoratis, ultimo anfractu serie quarta praedito, gemmis interdum versus basin evanidis, circa basin tribus liris succinctis; apertura quadrata, peristomate tenui, canali brevi, paullum recurvo.

Long. 10, lat. 3 mm.

Hab. Persian Gulf; Fao Cable, and along the north coast; not rare.

A fine species, of pronounced character. Cylindro-fusiform in shape, with channelled sutures, whorls (including the five nuclear, three of which are very finely striate) 16-17 in number, the lower whorls all ornamented with three equal spiral regular rows of gemmae, shining, round, large proportionately; the body-whorl possessing four, the lowest of them sometimes has the gemmae partly evanescent, the base being encircled with spiral plain ridges. Aperture somewhat squarrose, peristome thin, canal shortly recurved, pronounced. It may be compared with T. rufula, Watson, a somewhat smaller species * [footnote refers to: ‘Challenger’ Exp. xv. p. 566, pi, xlii. fig. 2] (long. 7.5 mm.) from Wednesday Island, Torres Straits. This is much of the same sculpture, with channelled suture, the shell being of a ruddy yellow tint throughout. It differs from T. idonea, M. & St., not only in the channelled sutures and greater breadth of contour, but in the mouth being more contracted. We have seen a live albino form from Fao; in this the fourth row of noduled gemmae at the periphery of the basal whorl is extremley distinct and perfect.

Translation of the Latin text.

Rather solid, pale yellow cylindro-fusiform shell; 16-17 whorls, the five apical ones with faint nice longitudinal striae, slightly decussated, the apex is delicate, rather flat; next whorls with deep sutures, a little convex; four apical whorls with two spiral cords, the next with three series of nodose gemmules, four in the last whorl with vanishing gemmules near the base which bears three smooth spiral cords; quadrate aperture, thin peristome, lightly recurved short anterior siphon.

Length 10, width 3 mm.

Diagnosis.

Syntypes between 7.5 and 8.4 mm high. Shell conical with 12 whorls bearing three spiral cords with tubercles at the intersection with orthocline axial ribs. The second spiral cord appears on the sixth whorl and becomes quickly as strong as the others. A smooth suprasutural cord is also visible. Growth lines are present. The peristome bears additional, although short, spiral cords and a shallow posterior sinus. The siphonal canal is short. On the base, the fourth cord is tuberculated and three more smooth cords are visible. The multispiral protoconch has four whorls: the first has abapically short axial riblets but it is too worn to be properly described, the other three have two spiral keels and axial riblets. Shell dirty white, with lighter tubercles.

Remarks.

According to Trew (1987), lot NHMUK 1921.1.28.18-20 contains the specimens figured by Melvill (1918). Therefore, upon inspection of the syntypes in NMW, a lectotype may be selected.

Figures

Figure 68. Triphora incolumis Melvill, 1918, Persian Gulf, Fao Cable. A-I Syntype NHMUK 1921.1.28.18: front (A, B), side (C, D), back (E), aperture (F), peristome (G), protoconch (H, I). J Original figure. K, L Syntypes NHMUK 1921.1.28.19 - 20: front views. Scale bars: A-E, K, L: 1 mm; F-G: 0.5 mm; H, I: 0.2 mm.