Leptochiton torishimensis ( Wu & Okutani, 1984 )

Sirenko, Boris I., 2020, New shelf and bathyal Philippine leptochitons (Mollusca: Polyplacophora Lepidopleurida), Zootaxa 4878 (3), pp. 467-500 : 483

Leptochiton torishimensis ( Wu & Okutani, 1984)

( Figs. 19 , 20 )

Hanleyella torishimensis Wu & Okutani 1984: 10 , pl. 5, figs. 10–14, pl. 7, figs. 1–11.

Leptochiton torishimensis ; Saito 1997: 44, pl. 1, fig. 7; 2001: 110; 2005: 103, fig. 2; Sirenko, 2018: 322 , figs 23–25.

Type material. Holotype ( UCM No. 30966), 1 paratype ( UCM No. 31840), and 3 paratypes ( NSMT No. 60005)

Type locality. Near Torishima Island , Japan, 31°7.8’N, 139°54.9’E, 310 m.

Material examined. Philippines. PANGLAO 2005, Bohol / Sulu seas, stn P4, 8°53.1’N, 123°33.5’E, 516–543 m, 3 spms (MNHN-IM-2013-67042), BL 5.1–14.0 mm, 26.05.2005 .

Distribution. Japan, from Suruga Bay to Amami-Oshima Island (177–350 m), Taiwan (170–1314 m) and now Philippines (516–543 m). This species is reported from Philippines waters for the first time and this find extends the distribution range of this species considerably.

Remarks. As a specimen collected from Taiwan ( Sirenko 2018), the Philippine specimen (MNHN-IM-2013- 67042) differs from the type specimen from Torishima Island, Japan by lacking irregular radial rows of granules on the lateral areas of the intermediate valves and the postmucronal area of the tail valve. The Philippine specimen possesses ten gills on each side, and a radula that is 5.8 mm long with 35 transverse rows of mature teeth. Each granule of the tegmentum of the present specimen has five to seven pores of aesthetes.

Figures

FIGURE 19. Leptochiton torishimensis, Philippines (MNHN-IM-2013-67042), BL 11.0 mm: A. Valve I, dorsal view; B. Valve II, dorsal view; C. Valve V, dorsal view; D. Valve VIII, dorsal view; E. Valve V, detail of tegmentum in central area; F. Valve V, rostral view; G. Valve VIII, lateral view; H. valve IV, ventral view.

FIGURE 20. Leptochiton torishimensis, Philippines (MNHN-IM-2013-67042), BL 11.0 mm: A. Dorsal and ventral scales and marginal needles; B. Radula; C. Dorsal scales and needles; D. Central and first lateral teeth of radula.