Leucosyrinx arcana, comb. nov.

Leucosyrinx arcana (E.A. Smith, 1899) comb. nov. Fig. 32C Pleurotoma (Surcula) arcana E.A. Smith, 1899: 239. Pleurotoma (Surcula) arcana – Annandale & Stewart 1909: pl. 9 figs 6, 6a. Comitas arcana – Powell 1969: 272 (23-284), pl. 219 figs 6–7, with query. — Tan & Islami 2021: 325, fig. 9a. Type material Syntypes ANDAMAN ISLANDS • 1 spec.; off Andaman Is.; 13°17′15″ N, 93°10′ E; depth 185 ftm (= 340 m); ZSI, M 926/1 • 1 spec.; off Travancore coast; 9°29′34″ N, 75°38′ E; depth 360 ftm (= 660 m); ZSI, M 926/1. Remarks Judging from the illustration in Annandale & Stewart (1909) the shell is rather similar to some of the molecularly confirmed species of Leucosyrinx, e.g., L. quinetae sp. nov. (Fig. 24) and some specimens of L. luzonica (Fig. 23). The position of the anal sinus, occupying the entire subsutural ramp, suggests the inclusion in Leucosyrinx rather than in Comitas and we transfer the species to Leucosyrinx. Sysoev (1996: figs 46–47) illustrated two specimens from the Gulf of Oman and the Gulf of Aden, identified by him as Comitas paupera (see below), which are very similar to the type of L. arcana and probably belong to this species. These specimens were collected at significantly larger depths, 1890– 2000 m. This assumption is based only on the shell characters and needs confirmation by anatomical and molecular data. Distribution From Gulf of Aden to Andaman Is. and Indonesia from 340 to 2000 m.