Acanthochitona intermedia ( Nierstrasz, 1905 )

Sirenko, Boris I. & Zhang, Junlong, 2019, Chitons (Mollusca: Polyplacophora) of Hainan Island and vicinity, South China Sea, Zootaxa 4564 (1), pp. 1-40 : 30

Acanthochitona intermedia ( Nierstrasz, 1905)

( Figs 4D , 22–24 )

Acanthochites intermedius Nierstrasz 1905: 56 , pl. 1, fig. 19, pl. 4, figs 109–114.

Acanthochitona intermedia ; Saito 2000: 23, fig. 7.

Acanthochiton sp.; Xu 2008: 458.

Type material. ITZ .

Type locality. Sanguisiapo , Banda, Indonesia (“Siboga” Expedition, stns. 93, 240, 0–12 m) .

Material examined. South China Sea, Xisha Islands, MBM 100328, 2 spms, BL 12.0–14.0 mm, 20.04.1958

Distribution. Indonesia, Xisha Islands, Japan (Amami Islands).

Remarks. The studied specimen (BL 14 mm) has a radula that is 4.5 mm long with 33 transverse rows of mature teeth and 14 gills extended from valve IV to valve VII. The species has previously been reported from Indonesia ( Nierstrasz 1905) and South Japan (Saito 2000). Due to the new record from Xisha Islands, the geographic range for this species is expanded.

Figures

FIGURE 4. Complete specimens of species of genera Plaxiphora, Placiphorella, Acanthochitona, and Cryptoplax: A. Plaxiphora bucklandnicksi, Hainan Island, Sanya, stn 13, BL 5.0 mm; B. Placiphorella stimpsoni, Hainan Island, Sanya, BL 23.0 mm; C. Acanthochitona britayevi, Hainan Island, Xincun, BL 8.0 mm; D. Acanthochitona intermedia, Xisha Islands, MBM 100328 BL 11.0 mm; E. Acanthochitona lanae, Hainan Island, stn 1 BL 5.0 mm; F. Cryptoplax larvaeformis, Xisha Islands, 57-419, BL 35.0 mm; G. Cryptoplax oculata, Xisha Islands, 57-419, BL 35.0 mm.

FIGURE 22. Acanthochitona intermedia, Xisha Islands, MBM 100328 BL 14.0 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 plurolateral and jugal areas; F. Valve V, rostral view; G. Valve VIII, lateral view; H. Valve IV, ventral view.

FIGURE 23. Acanthochitona intermedia, Xisha Islands, MBM 100328 BL 14.0 mm: A. Dorsal and ventral needles; B. Dorsal needles; C. Dorsal spicules around tuft; D. Ventral needles in middle part of girdle.

FIGURE 24. Acanthochitona intermedia, Xisha Islands, MBM 100328 BL 14.0 mm: A. Five transverse rows of radula; B. Central and first lateral teeth of radula.