Lucilina tilbrooki Milne, 1958

(Figs 13–15)

Lucilina tilbrooki Milne 1958: 152, figs 1–4; Kaas et al. 2006: 346, fig.145, map 51 (bibliography and synonymy); Dell’Angelo et al. 2010: 38, figs 2A–L, 3A–D, 4D–E; Sirenko 2012: 80, pl. 13 C, figs 21, 22. Tonicia (Lucilina) tilbrooki; Kaas & Van Belle 1980: 133; 1998: 188.

Type material. Holotype NMV P18471.

Type locality. Queensland, Capricorn Group, Heron Island .

Material examined. South China Sea, Hainan Island, stn. 5, 19°38’12’’N, 111°01′52’’E, intertidal, on stones, 2 spms, BL 4.0–6.0 mm, 14.11.2016, leg. B. Sirenko; stn. 15, 18°12’09’’N, 109°29′40’’E, intertidal, on old corals, 1 spm, BL 3.0 mm, 19.11.2016, leg. B. Sirenko; stn. 27, 18°18′03’’N, 109°13′55’’E, depth 2–5 m, on stones covered with red crustose algae, 1 spm, BL 9.5 mm, 24.11.2016, leg. B. Sirenko.

Distribution. The species is known from Maldives Islands, South Vietnam, Hainan Island and Australia.

Remarks. The studied specimen (BL 5.0 mm) has a radula 1.5 mm long with 35 transverse rows of mature teeth and 20 gills extending from valve III to valve VII. The slit formula of this specimen is 8/1/10. This is the first record of L. tilbrooki from Hainan Island.