Leptochiton belknapi Dall, 1878

Sirenko, Boris & Sellanes, Javier, 2016, Update of the genus Leptochiton (Mollusca: Polyplacophora) in Chilean deep waters: three new reports and description of two new species, Zootaxa 4173 (3), pp. 259-279 : 262-264

Leptochiton belknapi Dall, 1878

( Figs 1 A, B, 2–4)

Leptochiton belknapi Dall, 1878: 1 ; Kaas & Van Belle, 1987: 23, fig.10; Schwabe & Sellanes, 2010: 33, fig.1L–M; Sirenko, 2015: 154 –155.

Leptochiton alveolus ; Ferreira, 1979:152, fig 10 (in part, non Chiton alveolus M.Sars MS, Lovén, 1846); Kaas & Van Belle, 1985: 36, fig.14, map 6 (in part, non Chiton alveolus Lovén, 1846 ).

Leptochiton farallonis Dall, 1902: 557 .

Leptochiton mesogonus Dall, 1902: 555 . Leptochiton opacus Dall, 1908: 218 .

Leptochiton sp. Sellanes et al., 2004: 1066.

Type material. Holotype (USNM 30972).

Type locality. Off Western Aleutian Islands , 53°08’N, 171°19’W, 1840 m depth.

Material examined. Holotype; off Chile, RV AGOR Vidal Gormáz, st. VG07-7, AGT-8, 36.0023°– 36.0058°S, 73.3841° – 73.3706°W, 922–1013 m depth, 2 spms ( ZISP 2274 ), BL— 18–20 mm, 07.10.2007; RV Melville st. INSPIRE, AGT-3_533 , 36.22523°S, 73.43115°W, 724 m, 4 spms (SCBUCN 4136), BL— 12–30 mm, 0 9.03.2010.

Distribution. Widespread species, inhabits the Pacific Ocean from off Pacific side of Hokkaido (40°12’N), the Sea of Okhotsk and Bering Sea and North and South America’s Pacific waters southwards to 42°40’S, at depth of 100 to 3724 m, based on SEM examination of 23 specimens from the mentioned areas.

Revised diagnosis. Animal of moderate size, elongate oval. Intermediate valves subcarinated. Tegmentum sculptured with small granules evenly arranged quincuncially. Each granule with one megalaesthete and two micraesthetes positioned in front of megalaesthete. Dorsal side of girdle densely covered with pointed scales with 2–4 ribs. Central tooth of radula short and wide, major lateral tooth with big, unicuspid head and very small denticle (also termed appendix) at inner edge. Fifteen gills per side ranging from valve VII to anus.

Figures

FIGURE 1. Complete specimens of Leptochiton belknapi Dall, 1878. BL— 23 mm, RV Melville, st. INSPIRE, AGT- 3 _ 533, 724 m, SCBUCN 4136 (A, B), Leptochiton sigwartae Sirenko, 2015. BL— 33 mm, RV Sonne, st. SO- 156. 7176 - 5, 502 m, ZISP 2275 (C, D), Leptochiton laurae Schwabe & Sellanes, 2010. BL— 11,5 mm, RV Melville, st. INSPIRE, AGT- 2, 583. 497 – 574 m, ZISP 2276 (E, F), Leptochiton ibanezi sp. nov., holotype, BL— 21 mm, MNHNCL 400187 (G, H). A, C, E, G. Dorsal view; B, D, F, H. Lateral view. Scale bars 2 mm.