Triforis idoneus Melvill & Standen, 1901

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

Triforis idoneus Melvill & Standen, 1901

Figure 71

Triforis idoneus Melvill and Standen 1901: 376, pl. 22, fig. 17.

Type locality.

Linjah Anchorage (Iran).

Type material.

Syntypes: NHMUK 1901.12.9.219, 1 specimen, Linjah, Iran .

Original description.

T. testa anguste fusiformi, solida, calcareo-alba; anfractibus forsan quatuordecim, quorum apicales …?, caeteris (undecim) omnino regulariter spiraliter triseriatis, cancellatis, suturaliter impressis, ad juncturas nodulifero-gemmatis, nodulis regularibus, rectis, ultimo anfractu serie quarta praedito; apertura ovata; columella crassa; canali brevi, paullulum recurvo.

Long. 10, lat. 2.50 mm.

Hab. Linjah Anchorage, 5 fathoms.

This Triforis, distinguished by its uniform chalky whiteness and regular rows of gemmuled cancellations, coarse, uniform, three-ranked on all the upper whorls, four on the body-whorl, is of a graceful shape and fairly sized. It is unfortunate that all the specimens we have examined are without the apical whorls.

Translation of the Latin text.

Narrow fusiform shell, solid, chalky white; probably fourteen whorls, apical …?, others (eleven) with three regular spiral cords, cancellated and impressed sutures, noduliferous in their junction, straight regular nodules, last whorl with four rows; ovate aperture; thick columella; slightly recurved short anterior siphonal canal.

Height 10 mm, width 2.50 mm.

Diagnosis.

Syntype 10.4 mm high. Shell conical, with 13 whorls bearing three spiral cords with tubercles at the intersection with orthocline axial ribs. The second cord appears later on the teleoconch and attains full size only on the penultimate whorl. A thin smooth suprasutural spiral cord is also visible and attains full size on the base which has a fifth smooth spiral cord too. The peristome is missing, the siphonal canal appears moderately long. The protoconch is missing. The shell is whitish to yellowish but is very worn and colours may have faded away.

Remarks.

The original description refers to several specimens found, of which only this one has been located so far. The study of more syntypes would be precious to unambiguously identify this species: Melvill and Standen described "three-ranked on all the upper whorls", but the syntype has the second spiral cord developing later along the teleoconch.

Figures

Figure 71. Triforis idoneus Melvill & Standen, 1901, Linjah, Iran. A Original figure. B, C Syntype NHMUK 1901.12.9.219: front (B), side (C). D Original labels. Scale bar: B, C: 2 mm.