Ethusa quadrata Sakai, 1937

Castro, Peter, 2005, Crabs of the subfamily Ethusinae Guinot, 1977 (Crustacea, Decapoda, Brachyura, Dorippidae) of the Indo-West Pacific region, Zoosystema 27 (3), pp. 499-600 : 542-543

Ethusa quadrata Sakai, 1937

Ethusa quadrata Sakai, 1937: 76 (key), 78, figs 1c, 3; 1956: 7 (list), fig. 8.6; 1965: 24, pl. 12, fig. 3 (colour); 1976: 65, figs 26c, 28, pl. 23, fig. 3 (colour). — Serène 1968: 40 (list). — Takeda & Miyake 1970: 209; 1972: 68. — Serène & Lohavanijaya 1973: 35 (key). — Miyake 1983: 18, 198, pl. 6, fig. 4 (colour). — Serène & Vadon 1981: 120, 121. — Chen 1985: 191, fig. 10, pl. 1, fig. 7; 1986: 129, fig. 11; 1993: 318 (key), 319 (list). — Nagai 1995: 60, pl. 1, fig. 7. — Muraoka 1998: 17. — Takeda 2001: 225, 254, 259. — Chen & Sun 2002: 54, 241, fig. 102. — Komai et al. 2002: 20. — Marumura & Kosaka 2003: 23.

TYPE MATERIAL. — Holotype:, Japan, Honshu , Sagami Bay, between Ito and Hatsu Shima, Misago, stn 10, 80 m, VI.1934. Deposit unknown.

TYPE LOCALITY. — Japan, Honshu, Sagami Bay, between Ito and Hatsu Shima, 80 m.

MATERIAL EXAMINED. — Japan. Honshu, Kii Peninsula, W of Shionomisaki, 130 m, S. Nagai coll., VI.1998, 1 ( CBM-ZC 5026). — Sagami Bay, Kameki reef, 120 m, T. Sakai and Emperor Hirohito coll., 19.VI.1964, undet. sex ( SMF 28924).

Izu Islands, Hyotan-se Bank, 34°20.93’N, 139°04.78’E, 160-200 m, T. Komai coll., 22.X.1996, 1 ( CBM-ZC 4602).

Philippine Islands. South China Sea, MUSORSTOM 1, stn CP 62, 13°59.5’N, 120°15.6’E, 179-194 m, 27.III.1976, 1 ( MNHN-B 18170).

MUSORSTOM 2, stn CP 26, 13°49’N, 120°50’E, 299-320 m, 23.XI.1980, 1 ( MNHN-B 18171).

Bohol, Balicasag island, off Panglao island, tangle nets from local fishermen, 50-500 m, 28.XI.2001, 1 ( ZRC 2001.0517).

New Caledonia. BATHUS 2, stn DW 717, 22°44.82’S, 167°16.58’E, 350-393 m, 11.V.1993, 1 ( MNHN-B 28556).

BATHUS 4, stn DW 895, 20°15.40’S, 163°51.70’E, 315-350 m, 3.VIII.1994, 1 ( MNHN-B 28557).

NORFOLK 1, stn DW 1679, 24°43’S, 168°10’E, 298-324 m, 22.VI.2001, 1 ( MNHN-B 28558).

DISTRIBUTION. — Japan (see Sakai 1976), East China Sea ( Takeda & Miyake 1970; Chen 1986), Philippine Is ( Serène & Vadon 1981; Chen 1985), and now from New Caledonia. Depth: 35 ( Sakai 1965) - 393 m ( Fig. 34 ). It was also collected from fishing nets at depths of 50- 500 m.

SIZE. — Maximum size: cl 6.9 mm, cw 5.8 mm ( MNHN-B 28556), cl 8.4 mm, cw 7.3 mm ( MNHN-B 18171).

REMARKS

Ethusa quadrata is easily identified by the rectangular, nearly-square appearance of its carapace, with the sides straight and nearly parallel to each other ( Sakai 1937: fig. 3; 1965: pl. 12, fig. 5; 1976: fig. 28; Miyake 1983: pl. 6, fig. 4; Chen 1985: fig. 10; Chen & Sun 2002: fig. 102.1). The orbital sinuses are L-shaped, thus reinforcing the square appearance. Differences from E. furca Chen, 1993 , and E. hawaiiensis Rathbun, 1906 , which also have rectangular carapaces, are given in the respective discussions of these two species (see above).

Sakai (1937: 80) mentioned that “the animal is protected by a piece of bivalves”.

Figures

FIG. 34. — Bathymetric distribution of Indo-West Pacific ethusine crabs.