Lepidozona bisculpta

Sirenko, B. I., 2016, New and rare species of the genus Lepidozona (Mollusca: Polyplacophora) from the South China, East China and the Philippine seas, The Bulletin of the Russian Far East Malacological Society 20, pp. 28-46 : 32-36

Lepidozona bisculpta (Carpenter in Pilsbry, 1892)

Figs. 4–7 , 15A–C

Ischnochiton bisculptus Carpenter in Pilsbry, 1892: p. 119; Pilsbry, 1894, p. 83, pl. 17, figs. 60–61; Ferreira, 1978, p. 39.

Ischnochiton (Lepidozona) bisculptus Carpenter in Pilsbry, 1892: Leloup, 1941, p. 4, fig. 3, pl. 2, fig. 1.

Lepidozona bisculpta (Carpenter in Pilsbry, 1892): Ferreira, 1974, p. 164; Kaas, Van Belle, 1980, p. 17.

Lepidozona (Lepidozona) bisculpta (Carpenter in Pilsbry, 1892): Kaas, Van Belle, 1987, p. 227, fig. 103, map 43; Yum, 1988, p. 15; Choe, Yum, 1989, p. 263.

T y p e m a t e r i a l. Smithsonian Institution, US National Museum, USNM 24117. T y p e l o c a l i t y. China, Hong Kong.

M a t e r i a l e x a m i n e d. South China Sea , Tonkin Gulf: sample 192, 21 ° 02 ′ 09 ″ N, 107 ° 33 ′ 35.4 ″ E, SCUBA, 6–7 m, on old corals embeded in sand, 2 spms, BL 4–9 mm, 03.04.2014, leg. B. Sirenko ; sample 200, 21 ° 04 ′ 21.9 ″ N, 107 ° 33 ′ 34.3 ″ E, SCUBA, 16–20 m, on stones and old shell, 18 spms, BL 1.6–9 mm, 06.04.2014, leg. B. Sirenko ; sample 204, 20 ° 50 ′ 47.5 ″ N, 107 ° 19 ′ 19.7 ″ E, SCUBA, 17–20 m, on stones and old shell, 1 spm,BL 8.5 mm, 07.04.2014, leg. B. Sirenko ; sample 205, 20 ° 50 ′ 47.5 ″ N, 107 ° 19 ′ 19.7 ″ E, SCUBA, 12–15 m, on old shells, 1 spm, BL 17.5 mm, 07.04.2014, leg. B. Sirenko ; sample 206, 20 ° 53 ′ 58.6 ″ N, 107 ° 19 ′ 39.4 ″ E, SCUBA, 17–19 m, on old shells and stones, 1 spm, BL 7.0 mm, 07.04.2014, leg. B. Sirenko ; Hon Me Island ; sample 215, 19 ° 21 ′ 42.7 ″ N, 107 ° 19 ′ 19.7 ″ E, SCUBA, 6 m, on Pinna sp. , 1 spm, BL 12.5 mm, 16.04.2014, leg. B. Sirenko ; Taiwan : N/ O Fishery Researcher 1, TAIWAN 2000, stn CP 2, 23 ° 38.4 ′ N, 119 ° 53.3 ′ E, 85 m, 2 spms, BL 7–10 mm, 27.07.2000, leg. Ph. Bouchet, Richer , IRD and Chan ; stn CP 4, 23 ° 15.9 ′ N, 119 ° 50.9 ′ E, 129 m, 1 spm, BL 13 mm, 30.07.2000, leg. Ph. Bouchet, Richer , IRD and Chan.

D i s t r i b u t i o n. This is the first report of this species for Vietnam and Taiwan. L. bisculpta is known from west coast of Korea, Qingdao, China, Hong Kong and Vietnam.

R e m a r k s. The studied specimen ( Tonkin Gulf, sample 200), BL 8.0 mm has 20 gills ranged from valve III to valve VII, slit formula 11/1/9, radula 2.4 mm long with 26 transverse rows of mature teeth. Like previous species the specimen has more complicated composition of marginal scales than in Kaas and Van Belle [1987]. Marginal fringe composed of 5 different elements: slightly bent, smooth needles (160x15 μm), mounted on a chitinous sheath, flattened spicules, grooved in two directions (feather-like) (86x26 μm), wedge shaped, obliquely grooved spicules (80x31 μm), small, numerous, blunt-topped spicules (48x12 μm) with longitudinal ribs on top and short obtuse scales (42x30 μm).

Two specimens from Tonkin Gulf (samples 200 and 206) have abnormal number of valves: 7 valves in specimen with BL 8.0 mm and 5 valves in specimen with BL 7 mm .

L. bisculpta is very similar to L. coreanica (Reeve, 1847) and differs from the latter by absence of radial ribs in head valve and having 7–9 longitudinal ribs in dorsal scale (vs. 17–20 riblets in L. coreanica ).

Figures

Fig. 4. Lepidozona bisculpta, BL 8 mm, Vietnam, Tonkin Bay, 6–7 m, on old corals; 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 area; F – valve V,rostral view; G – valve VIII, lateral view.

Fig. 5. Lepidozona bisculpta, BL 8 mm, Vietnam, Tonkin Bay, 6–7 m, on old corals; A, B – dorsal scales, marginal spicules, scales and ventral scales; C, D – dorsal scales.

Fig. 6. Lepidozona bisculpta, BL 8 mm, Vietnam, Tonkin Bay, 6–7 m, on old corals; A – dorsal scales, marginal spicules, scales and ventral scales; B – radula.

Fig. 7. Lepidozona bisculpta, BL 8 mm, Vietnam, Tonkin Bay, 6–7 m, on old corals; A – dorsal scale; B–F – marginal needles, scales and spicules; G – ventral scale; H – central and lateral teeth of radula; I – head of major lateral tooth of radula. Scale bar 100 µm.

Fig. 15. Color images of species of genera Lepidozona. A – Lepidozona bisculpta, BL 8 mm, Vietnam, Tonkin Bay, 6–7 m, on old corals; B – Lepidozona bisculpta, with 5 valves, BL 8 mm, Vietnam, Tonkin Bay, 6–7 m, on old corals; C – Lepidozona bisculpta, with 7 valves, BL 8 mm, Vietnam, Tonkin Bay, 6–7 m, on old corals; D – Lepidozona acostata, holotype, BL 8 mm, south Vietnam, R/V Odissey, trawl 59, 310 m, on sunken wood; E – Lepidozona acostata, paratype, BL 8 mm, south Vietnam, R/V Odissey, trawl 59, 310 m, on sunken wood; F – Lepidozona excellens, holotype, BL 18.0 mm, Philippine Sea, R/V Odissey, stn 37, 380–420 m.