Ethusina vanuatuensis 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 : 578-579

Ethusina vanuatuensis Chen, 2000

Ethusina vanuatuensis Chen, 2000: 430 , fig. 4. — Ng & Ho 2003: 72 (list).

Ethusina robusta – Chen 1993: 342 (part); 2000: 430 (part) (not E. robusta ( Miers, 1886)) .

TYPE MATERIAL. — Holotype: cl 5.6 mm, cw 5. 3 mm, MUSORSTOM 8, stn CP 1026 ( MNHN-B 27520 ); paratype: cl 5.5 mm, cw 5.4 mm, MUSORSTOM 8, stn CP 1029 ( MNHN-B 27521 ).

TYPE LOCALITY. — Vanuatu, SE of Éfaté island, 17°50.35’S, 168°39.35’E, 437- 504 m.

MATERIAL EXAMINED. — Solomon Islands. SALOMON 1, stn CP 1781, 08°31.2’S, 160°37.7’E, 1036-1138 m, 20.IX.2001, 3 ( MNHN-B 28714).

Vanuatu. MUSORSTOM 8, stn CP 1125, 15°17.63’S, 166°38.43’E, 1160-1220 m, 28.IX.1994, 1 parasitized by Sacculina sp. ( MNHN-B 27517 ). — Stn CP 992, 18°52.34’S, 168°55.16’E, 775- 748 m, 29.IX.1994, 1 ovig. ( MNHN-B 28735 ). — Stn CP 1026, 17°50.35 ’S, 168°39.35’E, 437-504 m, 28.IX.1994, 1 holotype ( MNHN-B 27520 ) ; 1 ( MNHN-B 27519 ). — Stn CP 1129, 16°00.73’S, 166°39.94’E, 1014-1050 m, 10.X.1994, 1 paratype ( MNHN-B 27521 ) .

New Caledonia. BIOGEOCAL, stn CP 317, 20°48.38’S, 166°53.16’E, 1630- 1620 m, 2.V.1987, 1 ( MNHN-B 19097).

Fiji. BORDAU 1, stn CP 1398, 16°22’S, 179°56’W, 907-912 m, 24.II.1999, 1, 1 feminized by Sacculina sp. , 2, 1 ovig. ( MNHN-B 28644). — Stn CP 1400, 16°28’S, 179°50’W, 1004-1012 m, 26.II.1999, 2, 1 juv., 7, 2 ovig.

( MNHN-B 28645). — Stn CP 1413, 16°10’S, 179°24’W, 669-676 m, 26.II.1999, 1 parasitized by Sacculina sp. ( MNHN-B 28646). — Stn CP 1415, 16°31’S, 179°00’W, 670-682 m, 27.II.1999, 1 ( MNHN-B 28647). — Stn CP 1458, 17°22’S, 179°28 ’W, 1216-1226 m, 5.III. 1999, 2 ( MNHN-B 28648). — Stn DW 1459, 17°18’S, 179°33’W, 820-863 m, 5.III.1999, 1 undet. sex ( MNHN-B 28649).

DISTRIBUTION. — Known from Vanuatu ( Chen 2000) and New Caledonia ( Chen 1993, as E. robusta ( Miers, 1886) [part]), now from the Solomon Is and Fiji. Depth: 437-1226 m. and 1620-1630 m ( Fig. 34 ). SIZE. — Maximum size: 9.5 cl mm, cw 9.4 mm ( MNHN-B 28647), cl 8.1 mm, cw 8.2 mm ( MNHN-B 28645).

REMARKS

Diagnostic to Ethusina vanuatuensis is the presence in small males and juvenile females of slender outer orbital teeth that are directed slightly inwardly ( Chen 2000: fig. 4a) and, in males, G1 that have slightly pointed distal ends ( Chen 2000: fig. 4h). The G1 are very similar to those of E. dilobotus Chen, 1993 ( Chen 1993: fig. 17d-f). In E. dilobotus , however, the median lobes of the front are sinuous, concave, and lack terminal teeth.

Ethusinae of Indo-West Pacific ( Crustacea, Brachyura , Dorippidae )

In adult females, described here for the first time, the outer orbital teeth are relatively longer and the outer orbital sinus shallower than in males and juvenile females. The outer orbital teeth are directed slightly outwardly, a character also observed in the largest males. The median frontal sinus is broad in both sexes, the result of having medial frontal teeth that, at least in some small males (as in the holotype [MNHN-B 27521], Chen 2000: fig. 4a), slightly directed outwardly.

A large female from New Caledonia (cl 10.0 mm, cw 10.1 mm, MNHN-B 19097) parasitized by Sacculina sp. agrees with all diagnostic characters for E. vanuatuensis except that the outer orbital and frontal teeth are shorter than normal.

Figures

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