Isotriphora kurodai Kosuge, 1962

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

Isotriphora kurodai Kosuge, 1962

Figure 57

Isotriphora kurodai Kosuge 1962a: 84-85, pl. 10, fig. 7, text figs 11, 19.

Type locality.

Shirahama, Shimoda-machi, Shizuoka Prefecture, Central Japan.

Type material.

Holotype: reported in the Dr. T. Kuroda collection ( Kosuge 1962a) which is now in the Nishinomiya Shell Museum, Japan (not seen). Paratype: NHMUK 1966151: 1 specimen, Amami Islands, Japan .

Original description.

Shell medium in size, conical, apex blunt, not narrowed at the base, somewhat conoidal rod in shape. Protoconch immersed at the summit, slightly appearing as a tip of the smooth nucleus. Mature whorls 13, with straight side, suture deep and widely channelled. Sculpture 3 rows of granules, each row equal in size at the lower two-third of the spire, median row diminished at the early whorls. Granules connected with both spiral keels and rather broad axial columns which are latticed with spiral keels, apart by about half of its diameter and 22 to a whorl. On the body whorl, there are 3 smooth spiral keels on the periphery and base, anterior canal long and slightly recurved, aperture almost rounded. Colouration reddish brown and light brown in drifted materials.

Shell length: 7.4 mm.

Remarks: This species is easily recognized by its immersed protoconch, differing from Is. tasmanica (Ten-Wood) in its protoconch, of which the nucleus is slightly raised up, in contrast to the latter in which protoconch is completely immersed. This feature is taken natural as a generic character, therefore it may be necessary to give this species an appropriate subgeneric name.

This species is dedicated to Dr. Tokubei Kuroda of the Kyoto University, President of the Malacological Society of Japan, who is kind enough to help in both literature and material.

Figures

Figure 57. Isotriphora kurodai Kosuge, 1962, Amami Islands, Japan. A Original figure. B-I Paratype, NHMUK 1966151: front (B, C), side (D, E), back (F), protoconch (G), microsculpture (H), aperture (I). J NHMUK label. Scale bars: B-F: 1 mm; G: 0.2 mm; H: 0.3 mm; I: 0.5 mm.