Trifora concatenata Melvill, 1904

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

Trifora concatenata Melvill, 1904

Figure 67

Trifora concatenata Melvill 1904: 162, pl. 10, fig. 9.

Type locality.

"Gulf of Oman, lat. 24°58'N., long. 56°54'E., 156 fathoms".

Type material.

Syntypes: NHMUK 1905.7.14.32-4, 1 specimen (plus 2 belonging to another species, see Remarks), Gulf of Oman. Syntypes: NMW 1955.158.196, 18 specimens, Gulf of Oman (fide Trew 1987; not seen) .

Original description.

T. testa pergracili, multum attenuata, albescente, albo-fusca, anfractibus ad 18, quorum apicales 4, ochracei, spiraliter unicarinati, arete et pulcherrime sub lente longitudinaliter lirati, liris sinuosis, caeteris rectis, suturis indistinctis, tribus gemmularum ordinibus concatenatis praeditis, gemmulis rotundis, nitentibus, ultimo anfractu quatuor ordinibus, circa basim angulato, apertura rotundo-ovata, labro simplice, canali brevi. Long. 5, lat. 1 mm., sp. max.

A small, very gracefully attenuate species, white or whitish-drab, with ochreous apical whorls, these being once keeled spirally, the usual pattern being present on the remaining whorls of three rows of round, shining gemmae - four on the body-whorl, the lowest row being the largest; these spiral rows are more or less concatenate, leaving clear spaces between.

Translation of the Latin text.

Very slender thin shell, whitish, white-brown, up to 18 whorls, four unicarinated ochraceus apical ones, with microscopical sinuous lirae then becoming straight, indistinct sutures, three rows of concatenated gemmulae which are round, bright; last whorl with four rows, angulated near the base, rounded-ovate aperture, simple lip, short anterior siphon. The largest specimen is 5 mm long, 1 mm wide.

Diagnosis.

Syntype 5.6 mm high. Extremely slender shell with 14 flat teleoconch whorls bearing three spiral cords with tubercles at the intersection with prosocline axial ribs. The first spiral cord is smaller. The peristome is incomplete in the syntype, the siphonal canal appears short. On the base, three additional smooth cords are present. Protoconch incomplete, but clearly multispiral with the last three whorls bearing two spiral keels and axial riblets. Shell whitish.

Remarks.

Lot NHMUK 1905.7.14.32-4 contains three shells belonging to two species. One shell clearly resembles the specimen figured by Melvill (1904) ( NHMUK 1905.7.14.32, Fig. 67B-F ), while the other two can be readily distinguished by one instead of two spiral keels on the protoconch (Fig. 67J ) and the second spiral cord on the teleoconch appearing later than the other two (Fig. 67H, I ); in the true T. concatenata all three spiral cords are present since the first teleoconch whorl. According to Trew (1987), the specimen shown in Figure 67B is the syntype figured by Melvill (1904). Therefore, upon inspection of the syntypes in NMW, it may be selected as lectotype.

Figures

Figure 67. Trifora concatenata Melvill, 1904. A Original figure. B-F Syntype NHMUK 1905.7.14.32: front (B, C), side (D), protoconch (E), aperture (F). G-K Triphora sp. (not Trifora concatenata), NHMUK 1905.7.14.33, Gulf of Oman: front (G-H), side (I), protoconch (J), aperture (K). L Triphora sp. (not Trifora concatenata), NHMUK 1905.7.14.34, Gulf of Oman: side. M Original labels. Scale bars: B-D: 1 mm; F-I, L: 0.5 mm; E, J: 0.2 mm; K: 0.3 mm.