Ethusa obliquidens Chen, 1993

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 : 537-538

Ethusa obliquidens Chen, 1993

Ethusa obliquidens Chen, 1993: 317 (key), 330, fig. 11. TYPE MATERIAL. — Holotype: cl 9.1 mm, cw 8.3 mm, MUSORSTOM 4, stn DW 197 ( MNHN-B 22429 ); allotype: same station (IOAS); paratypes: cl 11.2 mm, cw 10. 8 mm, cl 11. 2 mm, cw 10.6 mm, MUSORSTOM 4, stn CP 169 ( MNHN-B 18418 ); cl 9.3 mm, cw 8.6 mm, MUSORSTOM 4, stn CP 198 (MNHN- B 18421).

TYPE LOCALITY. — New Caledonia, Grand Passage, 18°51.30’S, 163°21.90’E, 550 m.

MATERIAL EXAMINED. — Solomon Islands. SALOMON 1, stn CP 1795, 09°18.8’S, 160°22.9’E, 442-451 m, 1.X.2001, 1 ( MNHN-B 28546).

New Caledonia. MUSORSTOM 4, stn CP 169, 18°54.03’S, 163°11.20’E, 600 m, 17.IX.1985, 2 paratypes ( MNHN-B 18418). — Stn DW 197, 18°51.30’S, 163°21.90’E, 550 m, 20.IX.1985, 1 holotype ( MNHN-B 22429). — Stn CP 198, 18°49.40’S, 163°18.80’E, 590 m, 20.IX.1985, 1 paratype ( MNHN-B 18421).

BATHUS 4, stn CP 911, 18°57.80’S, 163°08.47’E, 566- 558 m, 5.VIII.1994, 3 ( MNHN-B 28576).

Fiji. MUSORSTOM 10, stn CP 1330, 17°09.5’S, 177°56.3’E, 567-699 m, 8.VIII.1998, 2 ( MNHN-B 28547).

Wallis and Futuna Islands. MUSORSTOM 7, stn DW 526, 13°13’S, 176°15’W, 355-360 m, 13.V.1992, 1 ( MNHN-B 28575). — Stn DW 537, 13°30’S, 176°41’W, 325-400 m, 16.V.1992, 1 ( MNHN-B 28573). — Stn DW 601, 13 °19’S, 176°17’W, 350 m, 23.V.1992, 1 juv. ( MNHN-B 28574).

DISTRIBUTION. — New Caledonia and now from the Solomon Is, Fiji, and the Wallis and Futuna Is. Depth: 325-699 m ( Fig. 34 ).

SIZE. — Maximum size: cl 9.1 mm, cw 8.3 mm ( MNHN-B 22429), cl 11.5 mm, cw 10.7 mm ( MNHN-B 28547).

REMARKS

Diagnostic to Ethusa obliquidens is the inward, oblique orientation of the triangular outer orbital teeth ( Chen 1993: fig. 11a, b). The sides of the carapace are slightly oblique rather than straight since the branchial region is somewhat inflated. The border of the endostome extends so much anteriorly that it reaches the ventral fold of the median central sinus and thus occludes a view of the antennular fossae of the basal antennular articles. Also characteristic are the fine, close-set granules, which give the carapace a file-paper texture. In a female specimen from the Solomon Is ( MNHN-B 28546), the only outer orbital tooth extant is very slender.

Figures

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