Ethusa sexdentata ( Stimpson, 1858 )

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 : 543-544

Ethusa sexdentata ( Stimpson, 1858)

Dorippe sexdentata Stimpson, 1858: 163 . — Bouvier 1906: 482.

Ethusa sexdentata – Stimpson 1907: 168, pl. 19, fig. 4. — Ihle 1916b: 153 (list), 156 (list). — Balss 1922: 120. — Yokoya 1933: 109, 211, 220. — Sakai 1936: 42, pl. 6, fig. 1 (colour); 1937: 76 (key), 77, 180, figs 1a, 2, pl. 11, fig. 1 (colour); 1956: 7 (list), fig. 8.3; 1965: 22, pl. 11, fig. 2 (colour); 1976: 63, fig. 26a, pl. 23, fig. 1 (colour). — Serène 1968: 40 (list). — Matsuzawa 1977: pl. 88 (colour). — Serène & Lohavanijaya 1973: 34 (key). — Takeda 1982:

fig. 275 (colour). — Miyake 1983: 18, 198, pl. 6, fig. 5 (colour). — Chen 1986: 126, fig. 8; 1993: 318 (key), 335, fig. 14. — Nagai 1995: 59, pl. 1, fig. 4. — Ng & Huang 1997: 267, fig. 3G (colour), 3H (colour). — Ikeda 1998: 26, pl. 16 (colour). — Muraoka 1998: 17. — Ng et al. 2001: 8. — Takeda 2001: 225, 254, 259. — Chen & Sun 2002: 54, 238 (part). — Marumura & Kosaka 2003: 23.

Not Ethusa sexdentata – Chen 1985: 185, figs 5, 6, pl. 2, figs 1, 2; 1997: 622. — Chen & Sun 2002: fig. 100 (= E. abbreviata n. sp.).

TYPE MATERIAL. — Most probably lost, like most of the type material of species described by Stimpson.

TYPE LOCALITY. — Kagoshima, Honshu, Japan.

MATERIAL EXAMINED. — Japan. Honshu, near Tokyo, Y. Harmand coll., 1906, 1 ( MNHN-B 24147). — Boso Peninsula, W of Katsuyama Uki Shima Islet, 120-180 m, M. Aizawa coll., 24.IV.1995, 2 ( CBM-ZC 1246). — Sagami Bay, Haberer leg, 1 juv. ( ZMB 17811). — Sagami Bay, Hayama, 120 m, H. Ikeda coll., 1 ( SMF 15128). — Sagami Bay, Kannonzuka-dasi and Amadaiba banks, 35°13’N, 139°33’E, 60-65 m, Hatagumo, T. Sakai and Emperor Hirohito coll., 22.VII.1957, 1 ( SMF 28932). — Aichi Prefecture, Off Mikawa, Mitani, R. Kamota coll., 18.II.1968, 1, 1 ( SMF 28923). Shikoku, Tosa Bay, K. Sakai coll., 1 ( SMF 11813).

Taiwan. TAIWAN 2000, stn CP 58, 24°35.1’N, 122°05.8’E, 221 m, 4.VIII.2000, 2 ( MNHN-B 28684).

TAIWAN 2001, stn CP 68, 24°49.6’N, 122°00.8’E, 370 m, 6.V.2001, 1, 1, 1 parasitized by Sacculina sp. ( MNHN-B 28695). — Stn CP 73, 24°52.9’N, 122°01.0’E, 220-330 m, 7.V.2001, 1 ( MNHN-B 28692). — Stn CP 75, 24°56.7’N, 120°01.8’E, 139 m, 7.V.2001, 1 feminized by Sacculina sp. ( MNHN-B 28685). — Stn CP 77, 24°54.2’N, 122°02.5’E, 360 m, 7.V.2001, 1, 1 parasitized by Sacculina sp. ( MNHN-B 28691). — Stn CP 79, 24°50.4’N, 121°59.9’E, 145-200 m, 8.V.2001, 1 ( MNHN-B 28687). — Stn CP 91, 24°50.6’N, 122°01.4’E, 400 m, 8.V.2001, 2 ( MNHN-B 28690). — Stn CP 94, 24°53.4’N, 121°58.1’E, 153 m, 10.V.2001, 1 ( MNHN-B 28688). — Stn CP 98, 24°54.2’N, 122°02.9’E, 362- 400 m, 18.V.2001, 1 ovig. ( MNHN-B 28693). — Stn CP 100, 24°53.2’N, 122°59.8’E, 223 m, 18.V.2001, 1 ( MNHN-B 28689). — Stn CP 104, 24°48.9’N, 122°05.3’E, 365-447 m, 19.V.2001, 1, 1 parasitized by Sacculina sp. ( MNHN-B 28686). — Stn CP 113, 24°50.8’N, 121°59.9’E, 281 m, 21.V.2001, 1 ( MNHN-B 28694).

TAIWAN 2003, stn CP 214, 24°28.59’N, 122°12.66’E, 490-1027 m, 27.VIII.2003, 3, 1 ( NTOU).

Philippine Islands. Sibuyan Sea, MUSORSTOM 3, stn CP 138, 11 °54’N, 122°15’E, 252-370 m, 6.VI.1985, 1 juv. ( MNHN-B 28018). — Stn CP 143, 11°29’N, 124°11’E, 205-214 m, 7.VI.1985, 2 ( MNHN-B 18929).

Bohol, Balicasag island, off Panglao island , tangle nets from local fishermen, XII.2000, 4 ( ZRC 2001.0388 ) ; 50-500 m, 28.XI.2001, 2, 4 ( ZRC 2001.0517 ) ; local shell fishermen, 200-300 m, VI.2002, 1 juv., 1 ( ZRC 2002.0642 ) ; purchased from fishermen, P. K. L. Ng et al., 25-30.VII.2003, 5 ( ZRC 2003.0296 ) .

DISTRIBUTION. — Japan (see Sakai 1976), East China and South China seas ( Chen 1986), Taiwan ( Ng & Huang 1997), and Philippine Is ( Chen 1993). Depth: 30 ( Sakai 1976) - 447 m ( Fig. 34 ). Also collected in tangle nets lowered to depths of 50- 500 m.

SIZE. — Maximum size: cl 25 mm, cw 24 mm ( Sakai 1976), cl 23.4 mm, cw 24.2 mm ( ZRC 2001.0517); no sex indicated: cl 30. 7 mm, cw 28.1 mm ( Ikeda 1998: pl. 16).

REMARKS

Ethusa sexdentata is a large-size species that is known from depths that are shallower than in the most species of ethusines. The outer orbital teeth are broadly triangular ( Sakai 1937: fig. 1a; 1965: pl. 11, fig. 2; 1976: fig. 26a; Chen 1993: fig. 14a). The endostome only extends to a point below the posterior border of the antennular fossae of the basal antennular articles. The G1 and G2 are illustrated by Chen (1986: fig. 8.39, 8.40).

Ethusa sexdentata has been confused with E. abbreviata n. sp. ( Chen 1985). Differences between the two species are discussed in the description of E. abbreviata n. sp. (see above).

Live specimens collected in gill nets in Chiba, Japan, as well as similarly collected specimens kept in aquaria were observed to carry bivalve shells or pieces of wood (T. Komai pers. comm.).

Figures

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