Leptoplax richardi (Kaas, 1990) n. comb.

Fig. 16

Notoplax (Notoplax) richardi Kaas, 1990: 178 –179, figs 1–10. Notoplax richardi: Kaas & Van Belle, 1998: 158 .

“ Notoplax ” sp. cf. richardi: Saito, 1998: 158 –160, fig. 8.

Type material. Holotype, MNHN-IM-2000-6111.

Type locality. Capel Bank, Coral Sea, 25°20´S, 159°44´E, 56 m.

Material examined. Southern Vietnam, Cau Id., 11°13.322´N, 108°49.866´E, 12–13 m, SCUBA, sand, tail valve, 14.05.2013, leg. B. Sirenko.

Distribution. Coral Sea; Southern Vietnam; Goto Islands, Japan, 6– 56 m.

Remarks. The tail valve (Fig. 16) which is the only known specimen of this species collected during the survey of collected sand is identifiable to Notoplax richardi Kaas, 1990 [= Leptoplax richardi (Kaas, 1990) n. comb.] described from Coral Sea, at the depth of 56 m by the outline of tegmentum, wavy margins of the jugum which has oblique sulci and 2–7 micraesthete pores distributed in the proximal half of the pustule.

The generic assignment of this species is changed from Notoplax to Leptoplax herein, based on the diagnostic features of the sutural laminae of the tail valve and the central part of the radula. The latter is shown in Saito (1998: 159, Fig. 8 A). This is the first record of this species from Vietnamese waters.