Leiosyrinx, Bouchet & Sysoev, 2001

Bouchet, P. & Sysoev, A., 2001, Typhlosyrinx - like tropical deep-water turriform gastropods (Mollusca, Gastropoda, Conoidea), Journal of Natural History 35 (11), pp. 1693-1715 : 1695-1696

Leiosyrinx n. gen.

Type species. Leiosyrinx immedicata n. sp.

Description. Shell rather large, adults about 30–40 mm high on average and up to 50 mm, with high spire and truncated canal. Protoconch with diagonally cancellated sculpture when multispiral. No axial sculpture. Sinus occupying subsutural ramp, rather shallow and broad. Operculum absent. Radular teeth small, less than 100 m m in length, simpli ed, with short blade.

Remarks. Conchologically, the species of Leiosyrinx are very similar to those of Typhlosyrinx and diOEer essentially in the absence of axial sculpture. This diOEerence by itself would not justify the erection of a new genus if it was not correlated with a diOEerence in radula. The teeth of species with axially ribbed teleoconchs measure 0.7–0.8% of shell height and have a barbed blade, those of species with smooth teleoconchs measure 0.23–0.26% of shell height and have a simpli ed unbarbed blade.

Etymology. From the Greek leios (adj.), smooth, with reference to the lack of axial sculpture, and su x - syrinx to recall the shell resemblance to Typhlosyrinx .

Allocation to a subfamily

Powell (1969) noted that the subfamily allocation of Typhlosyrinx was uncertain. He regarded the slender barbed toxoglossate teeth of T. vepallida and the absence of an operculum to be ‘daphnellid features’, but the absence of a diagonally cancellated protoconch and ‘turriculid style posterior sinus’ led him to locate ‘provisionally’ the genus in the Turriculinae . Our re-examination of the holotype of Typhlosyrinx vepallida shows that the early whorls are dissolved and the protoconch is missing. Therefore, the statement that the protoconch of T. vepallida is ‘globose and smooth’ ( Powell, 1969) is erroneous and must have been based on a wrong interpretation of Martens’ (1902) brief Latin diagnosis, which did not distinguish the protoconch whorls as such («... anfr. 8 AE, primus globosus, laevis, secundus subcylindricus, item laevis ... »). The paratype of T. praecipua , which is undoubtedly congeneric, has remnants of protoconch with diagonally cancellated sculpture. Likewise, Leiosyrinx neocaledoniensis n. sp. and L. matsukumai n. sp. have a diagonally cancellated multispiral protoconch. This indicates a position for Typhlosyrinx and Leiosyrinx in the subfamily Raphitominae .

The relationships of Typhlosyrinx and Leiosyrinx with other raphitomine genera are unclear. As noticed by Powell (1969), species of Typhlosyrinx are more similar to members of Cochlespirinae [5 Turriculinae ] than to any genus of R aphitominae. Species of Leiosyrinx have a super cial resemblance to such genera as Typhlodaphne Powell, 1951 (itself a genus of uncertain position but probably belonging to Raphitominae ) and Belaturricula Powell, 1951 (an operculate genus with weak anal sinus and smooth paucispiral protoconch indicating its position in Mangeliinae ), but diOEer from both by their shell being still more narrow and slender.

Composition

Species excluded. Barnard (1963) described three deep-sea South African species as Typhlosyrinx chrysopelex , T. pyrropelex and T. subrosea . However, re-examination of the type material has resulted in chrysoplex being reallocated to Gymnobela Verrill, 1884 , and T. pyrropelex and T. subrosea to Xanthodaphne Powell, 1942 ( Sysoev, 1996b) .

Species included. Typhlosyrinx vepallida ( Martens, 1902) ; T. praecipua (E. A. Smith, 1899) ; T. supracostata ( Schepman, 1913) ; T. panamica n. sp.; T. neocaledoniensis n. sp.; Leiosyrinx immedicata n. sp.; L. liphaima n. sp.; L. matsukumai n. sp.; L. apheles n. sp.