Triforis (Ino) excelsior Melvill & Standen, 1899

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 (Ino) excelsior Melvill & Standen, 1899

Figure 70

Triforis (Ino) excelsior Melvill and Standen 1899: 166, pl. 10, fig. 5.

Type locality.

Torres Strait.

Type material.

Syntypes: NHMUK 1899.2.23.18, 1 specimen, Torres Strait. Syntypes: NMW 1955.158.204, 1 specimen, Torres Strait and MSIM, 4 specimens, Torres Strait (fide Trew 1987; not seen) .

Original description.

T. testa producta, multum attenuata, angusta, brunnea, hic illic rufo-maculata; anfractibus quinque- vel sex-et-viginti, tornatis, apud suturas elevatis, transversim arcte tricarinatis, laevibus; carina infra, juxta suturas, minore, duabus alteris magis conspicuis, interstitiâ interveniente planata, ultimo anfractu quadricarinato, carina bina ad peripheriam addita; apertura rotunda, parva, canali breviter recurvirostri, in uno specimine pone aperturam ipsam clausa. Long. 30, lat. 5 (sp. maj.) mm.

Four or five, mostly imperfect, examples. The form is much acuminate and attenuate, narrow; colour light brown, here and there indistinctly flecked with rufous spotting; whorls 25 or 26, tornate, smooth, elevated at the sutures, closely thrice-keeled transversely, the keel just below the sutures is smaller and less conspicuous than the two lower, the last whorl is four-keeled, there being two on the periphery; the aperture is roundish, small; in one (the most perfect) specimen the recurved and beaked canal is closed with shelly matter behind the aperture.

The only species to which, in size, this very conspicuous Triforis could be referred is T. gigas, Hinds, also occurring in the same localities. The sculpture, as seen by the above description, is however totally different, being smooth, with no interstitial pitting or gemmuled ribs of any kind. Owing to no one specimen being in a state of absolute perfection, we have been compelled to estimate the number of whorls and the dimensions generally with the aid of two or more examples, each complete in some one particular.

Translation of the Latin text.

Much acuminate and slender narrow shell, brown in colour with reddish spots; twenty-five or twenty-six elegant whorls, elevated at the sutures, with three spiral keels; the keel just below the suture is smaller and less conspicuous than the other two, interspaces flat; the last whorl is four-keeled, a double keel is present at the periphery; the aperture is roundish, small; the bent and beaked anterior siphonal canal in one specimen is closed with shelly matter behind the aperture. The largest specimen is 30 mm high and 5 mm wide.

Diagnosis.

Syntype 24 mm high. Shell narrowly pyramidal, very slender with 22 whorls bearing three smooth spiral cords, the second being smaller than the others. A fourth smooth suprasutural spiral cord is visible. Between the main cords, there are prosocline axial riblets. The peristome is a bit broken in the syntype, but clearly bears additional spiral cords. Base with a fifth smooth spira cord. Siphonal canal long. Apex missing. Teleoconch whitish with few small brown blotches.

Figures

Figure 70. Triforis excelsior Melvill & Standen, 1899, NHMUK 1899.2.23.18, Torres Strait. A Original figure. B-D, F Syntype: front (B), side (C), back (D), peristome (F). E Original labels. Scale bar: B-D: 3 mm.