Ethusa hawaiiensis Rathbun, 1906

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 : 523-524

Ethusa hawaiiensis Rathbun, 1906

( Figs 9 ; 10 ; 33B )

Ethusa mascarone hawaiiensis Rathbun, 1906: 891 , fig. 46, pl. 15, fig. 4. — Ihle 1916b: 153 (list), 155 (list). — Serène 1968: 40 (list).

Ethusa hawaiiensis – Serène & Lohavanijaya 1973: 34 (key). — Chen 1993: 318 (key, list).

TYPE MATERIAL. — Holotype: cl 7. 6 mm, cw 6.9 mm, Albatross, stn 4101 ( USNM 29930 ).

TYPE LOCALITY. — Hawaiian Islands, Pailolo Channel between Molokai and Maui, 262- 223 m.

MATERIAL EXAMINED. — Vanuatu. MUSORSTOM 8, stn CP 963, 20°20.10’S, 169°49.08’E, 400-440 m, 21.IX.1994, 1 ( MNHN-B 28538).

French Polynesia. Marquesas Islands, MUSOR- STOM 9, stn DW 1146, 09°19’S, 140°06’W, 200 m, 22.VIII.1997, 1 ( MNHN-B 28552), 1 ( MNHN-B 28553). — Stn DR 1198, 09°50’S, 139°09’W, 290-320 m, 28.VIII.1997, 1 ovig.

( MNHN-B 28550). — Stn CP 1268, 07°56’S, 140°43’W, 285-320 m, 4.IX.1997, 3 ( MNHN-B 28551).

Hawaiian Islands. Albatross, stn 3810, off south coast of Oahu, 368- 97 m, 27.III.1902, 1 ( USNM 29928). — Stn 4101, Pailolo Channel, 262- 223 m, 23.VII.1902, 1 holotype ( USNM 29930). — Stn 4045, off west coast of island of Hawaii, 362- 269 m, 11.VII.1902, 1 ( USNM 29929).

DISTRIBUTION. — Known from the Hawaiian Is and now from Vanuatu and French Polynesia (Marquesas Is ). Depth : 200-440 m ( Fig. 34 ) ; also collected in a trawl from 97-386 m ( Rathbun 1906).

SIZE. — Maximum size: cl 5.0 mm, cw 4.0 mm ( USNM 29929), cl 7.6 mm, cw 6.9 mm ( USNM 29930).

REMARKS

Ethusa hawaiiensis has a rectangular carapace with straight sides that are almost parallel to each other ( Fig. 9 ), a character it shares with E. quadrata Sakai, 1937 , and E. furca Chen, 1993 . The outer orbital teeth are much shorter, almost like a tubercle, in contrast to the more conspicuous teeth in E. quadrata ( Sakai 1937: fig. 1c; 1965: pl. 12, fig. 3; 1976: fig. 26c; Chen 1985: fig. 10a). The lower margin of the orbital sinus is straight and provided with minute tubercles, not sinuous as in E. furca ( Chen 1993: fig. 4a). The median frontal teeth are longer than the lateral ones. Both are pointed, unlike E. furca , where the median teeth are lobe-like. The anteri- or border of the endostome reaches the posterior border of the antennular fossae of the basal antennular articles, unlike both E. quadrata and E. furca , where the border of the endostome is well below the fossae.

The G1 and G2 are here illustrated for the first time. The G1 ( Fig. 10B ) are short, stout, each with a blunt, rounded tip provided with spinules. Each G2 ( Fig. 10C ) has a pointed tip also provid- ed with spinules.

Figures

FIG. 9. — Ethusa hawaiiensis Rathbun, 1906, cl 4.9 mm, cw 4.2 mm, French Polynesia, Marquesas Islands, Ua Pou, MUSORSTOM 9, stn DW 1146, 200 m (MNHN-B 28552).

FIG. 10. — Ethusa hawaiiensis Rathbun, 1906, cl 4.9 mm, cw 4.2 mm, French Polynesia, Marquesas Islands, Ua Pou, MUSORSTOM 9, stn DW 1146, 200 m (MNHN-B 28552); A, abdomen; B, right G1, dorsal view; C, right G2, ventral view. Scale bars: 1 mm.

FIG. 33. — A, Ethusa granulosa Ihle, 1916, cl 14.7 mm, cw 14.6 mm, Vanuatu, west coast of Malekula, MUSORSTOM 8, stn DW 1061, 458-512 m (MNHN-B 28698) (photograph by J.-L. Menou, IRD, Nouméa); B, Ethusa hawaiiensis Rathbun, 1906, cl 6.7 mm, cw 6.2 mm, Vanuatu, S of Anatom, MUSORSTOM 8, stn CP 963, 400-440 m (MNHN-B 28538) (photograph by J.-L. Menou, IRD, Nouméa); C, Ethusa indica Alcock, 1894, cl 7.8 mm, cw 7.8 mm, Vanuatu, SE of Éfaté, MUSORSTOM 8, stn CP 1036, 920-950 m (MNHN-B 28560) (photograph by J.-L. Menou, IRD, Nouméa); D, Ethusina challengeri (Miers, 1886), cl 25.9 mm, Mid-Indian Basin, SAFARI 2, stn 35, trawl CP 29, 4950-4928 m (MNHN-B 28697) (photograph by P. Briand, IFREMER); E, Ethusina macrospina Ng & Ho, 2003, cl 10.4 mm, cw 11.0 mm, Taiwan, off southwest coast, TAIWAN 2003, stn CD 203, 635-868 m (NTOU) (photograph by T.-Y. Chan, NTOU).

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