Leptochiton longispinus Saito, 2001

(Figs. 6–8)

Leptochiton longispinus Saito 2001: 111, figs 6, 7, pl. 1, figs 4–6.

Type material. Holotype (NSMT-Mo 72764), 4 paratypes (NSMT-Mo 72765–72767).

Type locality. Japan, central part of Tosa Bay (621–622 m) (Saito 2001).

Material examined. Philippines, AURORA 2007, stn CC 2701, 14°48’N, 123°16’E, 709–718 m, 1 spm (MNHN-IM-2013-67052), BL 13.0 mm, 27.05.2007.

Distribution. Japan, Tosa Bay (621–622) and now off Philippines (709–718 m).

Remarks. The studied specimen (MNHN-IM-2013-67052) is damaged, lacking the head valve. It has 14–17 pores of aesthetes in each granule, 14 gills arranged from valve VI to near the anus, a radula 5.8 mm long with 35 transverse rows of mature teeth. The species belongs to the group of L. rissoi-L. vietnamensis and differs from the other species of this group by having 14–17 aesthete pores in the granules of the central areas (vs. 7–9 pores in L. rissoi, 18–21 pores in L. vietnamensis). Moreover, the central tooth of the radula of L. longispinus shows a longitudinal rib (vs. no longitudinal rib in L. rissoi), the granules in the central areas are separated from each other in L. longispinus (vs. granules overlapping each other in L. vietnamensis).