Leiosyrinx liphaima, 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 : 1706-1708

Leiosyrinx liphaima n. sp.

(gures 35–39)

Type material. H olotype and paratype M N H N.

Type locality. Coral Sea, Chester eld Plateau, 19ss27¾S, 158ss40¾E, 290 m [Musorstom 5, sta. 353].

Material examined. Coral Sea. M usorstom 5: Sta. 335, 20ss03¾S, 158ss45¾E, 315 m, one dd (paratype, gures 37–39). Sta. 353, 19ss27¾S, 158ss40¾E, 290 m, one dd (holotype, gures 35, 36).

Distribution. Coral Sea, Chester eld Plateau, shells in 290– 315 m.

Description. Holotype (gures 35, 36). Shell slender, solid, spire occupying 37% of total shell height. Protoconch paucispiral, of about 1.5 whorls [protoconch/ teleoconch transition indistinct], diameter ca 650–700 m m, surface eroded. Teleoconch whorls eight, weakly convex, suture shallow, impressed, subsutural ramp attened, slightly concave on last whorl. No axial sculpture except strong wrinkles in subsutural ramp of rst teleoconch whorls and incremental lines. Spiral cords low, broad, separated by narrow grooves, strong and even on subsutural ramp, weakly de ned and uneven on periphery. Shell base not diOEerentiated from canal. Aperture oval, inner lip evenly concave, with distinct continuations of spiral cords under very thin callus. Anal sinus deepest at about mid-point of subsutural ramp, outer lip strongly projecting below sinus. Canal short, broadly open. Colour white, with very pale orange band on base and brownish orange markings on subsutural ramp.

Dimensions: shell height 30.4 mm, last whorl height 18.8 mm, aperture height 15.1 mm, diameter 9.6 mm.

The paratype (dimensions 21.7 Ö6.5 mm; gures 38, 39) is very similar to the holotype, except for slightly broader cords on last whorl. The paucispiral protoconch, diameter 700 m m, consists of 1.4 whorls sculptured by wavy, closely packed spiral cords (gure 37).

Remarks. Leiosyrinx liphaima is very similar to L. immedicata , and diOEers from it in its paucispiral protoconch and much paler colour pattern. Leiosyrinx liphaima and L. immedicata are a classic case of a species pair diOEering in the mode of development, a phenomenon which has been shown to occur repeatedly in the turrids ( Bouchet, 1990). The protoconch of L. immedicata indicates planktotrophic larval development, although of probably rather short duration in view of the less than two protoconch II whorls, whereas the protoconch of L. liphaima indicates nonplanktotrophic larval development, although a short planktonic demersal stage may be present. It is probable that L. immedicata or its immediate ancestor dispersed to the Chester eld Plateau through planktotrophic veligers and subsequently speciated through loss of planktotrophy.

Etymology. The epithet is latinized from the Greek liphaimos (adj.), meaning lacking blood, pale, in reference to the colour diOEerence from the related L. immedicata .