Ethusa sinespina Kensley, 1969

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 : 544

Ethusa sinespina Kensley, 1969

Ethusa sinespina Kensley, 1969: 151 , 161, 177, fig. 4; 1974: 63; 1981b: 38 (list). — Chen 1987: 686, fig. 5, pl. 2, fig. C; 1993: 318 (key), 319 (list).

? Ethusa sinespina – Marumura & Kosaka 2003: 23.

? Ethusa sp. – Kensley 1981a: 60.

TYPE MATERIAL. — Holotype: cl 7.0 mm, cw 6.8 mm, Anton Bruun, stn BRU 390 E ( SAM

A12648 ); paratype: cl 4.9 mm, cw 5.0 mm, Anton Bruun, stn BRU 390 S ( SAM A12649) .

TYPE LOCALITY. — South Africa, off Natal, 29°42’S, 31°38’E, 350 m.

MATERIAL EXAMINED. — South Africa. Anton Bruun, stn BRU 390 E, 29°42’S, 31°38’E, 350 m, 8.IX.1964, 1 ovig. holotype ( SAM A12648). — Stn BRU 390 S, 29°35’S, 31°42’E, 138 m, 9.IX.1964, 1 juv.

paratype ( SAM A12649).

Madagascar. Vauban, trawling, 12°40.0’S, 48°09.5’E, 185-205 m, A. Crosnier coll., 1.VIII.1973, 1 ( MNHN-B 18361).

DISTRIBUTION. — South Africa ( Kensley 1969) and Madagascar ( Chen 1993). Depth: 138-350 m ( Fig. 34 ).

SIZE. — Maximum size: cl 6.3 mm, cw 6.3 mm ( MNHN-B 18361), cl 7.0 mm, cw 6.8 mm ( SAM A12648).

REMARKS

Ethusa sinespina is very close to E. zurstrasseni Doflein, 1904 , from East Africa. Kensley (1969: 162) separated his new species from E. zurstrasseni by the absence of a “minute spine between the pairs of frontal teeth”, the outer orbital teeth not being dorsoventrally flattened, and shallower grooves on the dorsal surface of the carapace.

A comparison of the type material of E. sinespina with the holotype of E. zurstrasseni (cl 7.2 mm, cw 6.8 mm, ZMB 13629) shows that these differences are minor if not erroneous. The holotype does not show the minute spine mentioned in the description, the outer orbital teeth are triangular and certainly dorsoventrally flattened in both species, and there are no clear, obvious differences in the definition of the regions of the carapace. Not mentioned in the description of either species is the anterior border of the endostome. In both species it extends well above the antennular fossae in such a way that it almost reaches the ventral fold of the median central sinus (Chen 1987: fig. 5b). The only outstanding difference between the two species are the G1. Each pleopod has many minute spines and a widened tip in E. sinespina (Chen 1987: fig. 5e), whereas it has a slender, pointed tip in E. zurstrasseni ( Fig. 15 ; Chen 1987: fig. 3e, as E. madagascariensis ).

Figures

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

FIG. 15. — Ethusa zurstrasseni Doflein, 1904, holotype cl 7.2 mm, cw 6.8 mm, southern Somalia, Deutsche Tiefsee Expedition, Valdivia, stn 254, 977 m (ZMB 13629), right G1, distal part, ventrolateral (left) and dorsolateral (right) views. Scale bar: 1 mm.