Onithochiton stracki Sirenko, 2012

Sirenko, Boris I. & Zhang, Junlong, 2019, Chitons (Mollusca: Polyplacophora) of Hainan Island and vicinity, South China Sea, Zootaxa 4564 (1), pp. 1-40 : 21

Onithochiton stracki Sirenko, 2012 .

( Figs 3E , 16–18 )

Onithochiton stracki Sirenko 2012: 85 , pl. 13 B, figs 25, 26.

Type material. Holotype ( ZISP 2175 ).

Type locality. South China Sea , off South Vietnam, Nhatrang Bay, Nok Island .

Material examined. South China Sea, China, Hainan Island. Xincun, sample 1, 1 spm, BL 17.0 mm, 19.04.1958, leg. O. Scarlato; stn 22, 18°11’46’’N, 109°29’40’’E, depth 2 m, on old corals, 1 spm, BL 5.0 mm, 21.11.2016, leg B. Sirenko; stn 26, 18°11’46’’N, 109°29’40’’E, intertidal–1.5 m, on stones, 3 spms, BL 3.0–12.0 mm, 22.11.2016, leg. B. Sirenko, S. Grebelniy.

Distribution. South China Sea, Vietnam from Phu Quy Island to Danang and Hainan.

Remarks. The studied specimen (BL 11.0 mm) has a radula 3.4 mm long with 36 transverse rows of mature teeth and 11 gills extended from valve II to valve VII. The slit formula of this specimen is 8/1/0. Specimens of this species from Hainan Island differ from Onithochiton hirasei from Guangdong Province by having a coarser sculpture of the tegmentum and larger spicules of girdle. This is the first find of O. stracki from Hainan Island.

Figures

FIGURE 3. Complete specimens of species of genera Lucilina, Onithochiton and Acanthopleura: A. Lucilina lamellosa forma typica, Xisha Islands, 58M-1246, BL 28.0 mm; B. Lucilina lamellosa forma costata, Hainan Island, 55-640, BL 21.0 mm; C. Lucilina tenuicostata, Hainan Island, stn 13, BL 10.0 mm; D. Onithochiton cf. hirasei, Guangdong Province, BL 29.0 mm; E. Onithochiton stracki, Guangdong Province, BL 19.0 mm; F. Acanthopleura loochooana, Hainan, stn 28, BL 26.0 mm.

FIGURE 16. Onithochiton stracki, Hainan, Sanya, stn 26, 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 and lateral areas; F. Valve V, rostral view; G. Valve IV, ventral viev; F. Valve VIII, lateral view.

FIGURE 17. Onithochiton stracki, Hainan, Sanya, stn 26, BL 11.0 mm: A. Dorsal and marginal spicules and ventral scales; B. Dorsal and marginal spicules; C. Dorsal spicules; D. Ventral scales in central part of girdle.

FIGURE 18. Onithochiton stracki, Hainan, Sanya, stn 26, BL 11.0 mm: A. Four transverse rows of radula; B. Central and first lateral teeth of radula.