Ethusina microspina Chen, 2000

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 : 565-566

Ethusina microspina Chen, 2000

Ethusina microspina Chen, 2000: 428 , figs 1, 2, 5. — Ng & Ho 2003: 72 (list).

T Y P E M A T E R I A L. — Holotype: cl 5.9 mm, cw 6. 0 mm, MUSORSTOM 8, stn CP 9 9 2 (MNHN-B 2 7 5 1 2); paratypes: cl 6.2 mm, c w 5. 8 m m, M U S O R S T O M 8, s t n C P 1 0 7 4 ( MNHN-B 27514 ); cl 8.7 mm, cw 8.6 mm; cl 8.3 mm, cw 8.4 mm, MUSORSTOM 8, stn CC 996 ( MNHN-B 27513 ).

TYPE LOCALITY. — Vanuatu, E of Erromango island, 18°52.34’S, 168°55.16’E, 775-1200 m.

MATERIAL EXAMINED. — Solomon Islands. SALOMON 1, stn CP 1783, 08°32.8’S, 160°41.7’E, 399-700 m, 29.IX.2001, 1 juv. ( MNHN-B 28650).

Vanuatu. MUSTORSTOM 8, stn CP 9 9 2, 18°52.34’S, 168°55.16’E, 775- 748 m, 24.IX.1994, 1 holotype ( MNHN-B 27512). — Stn CC 996, 18°52.41’S, 168°55.73’E, 764-786 m, 24.IX.1994, 1 paratype, 1 ovig. paratype ( MNHN-B 27513). — Stn CP 1074, 15°48.42’S, 167°24.27’E, 775-798 m, 4.X.1994, 1 paratype ( MNHN-B 27514).

Fiji. MUSORSTOM 10, stn CP 1330, 17°09.5’S, 177°56.3’E, 567-699 m, 8.VIII.1998, 1 ovig.

( MNHN-B 28651).

BORDAU 1, stn CP 1392, 16°49’S, 179°54’E, 545- 651 m, 23.II.1999, 1, 2 ( MNHN-B 28652). — Stn DW 1397, 16°33’S, 179°52’W, 674-688 m, 24.II.1999, 1 ( MNHN-B 28653). — Stn CP 1413, 16°10’S, 179°24’W, 669-676 m, 26.II.1999, 2, 1 feminized by Sacculina sp. ( MNHN-B 28654). — Stn DW 1419, 17°05’S, 178°55’W, 654-656 m, 28.II.1999, 1 ( MNHN-B 28655). — Stn DW 1491, 18°50’S, 178°27’W, 778-787 m, 11.III.1999, 1 ( MNHN-B 28656). — Stn DW 1493, 18°43’S, 178°24’W, 429-440 m, 11.III.1999, 1 ( MNHN-B 28657).

French Polynesia. Austral Islands, BENTHAUS, stn DW 1889, 27°36.8’S, 144°15.7’W, 600-620 m, 7.XI.2002, 6 juv. ( MNHN-B 28831). — Stn DW 1898, 27°34.3’S, 144°26.6’W, 580-820 m, 8.XI.2002, 1 juv. ( MNHN-B 28833). — Stn DW 1910, 27°38. 2’S, 144°15.4’W, 840-1200 m, 10.XI.2002, 1 juv., 1 ovig. ( MNHN-B 28835). — Stn CP 1909, 27°38.6’S, 144°15.6’W, 783-1000 m, 10.XI.2002, 1 ( MNHN-B 28830). — Stn DW 1923, 27°01.3’S, 146°05.3’W, 360-840 m, 11.XI.2002, 1 juv. ( MNHN-B 28832). — Stn DW 1943, 23°48.7’S, 147°39.1’W, 950 m, 15.XI.2002, 1 ( MNHN-B 28829).

DISTRIBUTION. — Known from Vanuatu ( Chen 2000) and now from the Solomon Is, Fiji, and French Polynesia (Austral Is). Depth: 360-798 m; also collect- ed in a trawl from 840 to 1200 m ( Fig. 34 ).

SIZE. — Maximum size: cl 10.5 mm, cw 10.5 mm ( MNHN-B 28829), cl 12.5 mm, cw 12.3 mm ( MNHN-B 28830).

REMARKS

As in Ethusina brevidentata Chen, 1993 , the outer orbital teeth of E. microspina are minute. In E. microspina , however, the width of the orbital sinuses is greatly reduced and the sinuses are oriented at the same angle as the sides of the carapace so that the outer orbital teeth appear as minute lateral teeth, giving the appearance that there is a total of only four teeth along the anteri- or border ( Chen 2000: figs 1a, 2a, 5). The outer orbital teeth are very small or even absent in large females ( Chen 2000: figs 2a, 5b). In contrast, in E. brevidentata the orbital sinuses are clearly demarcated beyond the lateral teeth so that there are six teeth along the anterior border ( Chen 1993: fig. 16a, b), the same number as in the remaining Indo-West Pacific species of Ethusina . Chen (2000: 428) lists other difference between the two species.

Figures

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