ETHUSINAE Guinot, 1977

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 : 505-506

Subfamily ETHUSINAE Guinot, 1977

Dorippinae Alcock, 1896: 273 , 274 (part).

Ethusinae Guinot, 1977: 1052 ; 1978: 249. — Manning & Holthuis 1981: 29, 38. — Guinot & Bouchard 1998: 651.

TYPE GENUS. — Ethusa Roux, 1830 .

GENERA INCLUDED. — Ethusa Roux, 1830 , Ethusina Smith, 1884 , and Parethusa Chen, 1997 .

DIAGNOSIS. — Afferent branchial openings circular or oval, placed against bases of chelipeds; cavity of each afferent branchial opening, arthrodial cavity of P1 contiguous. Efferent branchial openings formed by triangular anterior prolongation of endostome. Sternal suture 5/6 straight, without concavity. Antennules long, projecting beyond fossae, obliquely folded. Third maxillipeds with epipodite completely occluding afferent branchial opening; exopodite with multiarticulated flagellum. P2, P3 long, typically slender; P4, P5 shorter, directed dorsally over carapace; dactyli of P4, P5 short, curved, not subchelate (not pressing against tubercle on propodi). First three abdominal somites visible in dorsal view. Male abdomen with six somites plus telson, narrower than sternum, both sides nearly parallel to each other; somites 3-5 fused; locking mechanism with very low to medium-size tubercle at edge of thoracic sternite 5, shallow socket on underside (ventral surface) of abdominal somite 6. Soft, often basally enlarged penis emerging at end of penis tube extending from P5 coxa into thoracic sternite 8. G1 slender to slightly stout; G2 slender, as long as or slightly longer than G1. Abdomen of mature females rounded, broad; triangular in immature females. Vulvae on thoracic sternite 5, large, slightly raised, covered by movable membranes. Locking mechanism persists in adult females as two low to medium-sized tubercles at center of thoracic sternite 4, shallow concavity on underside (ventral surface) of abdominal somite 6.

REMARKS

The genera Ethusa Roux, 1830 , and Ethusina Smith, 1884 were traditionally grouped togeth- er with Dorippe Weber, 1795 , in the nominative subfamily of the Dorippidae . Serène & Romimohtarto (1969) subsequently divided the genus Dorippe into three genera and two subgenera, which were raised to genera by Manning & Holthuis (1981). Guinot (1977, 1978) recognized a second subfamily, the Ethusinae , for the genera Ethusa and Ethusina . A third genus, Parethusa Chen , 1 9 9 7, was more recently added.

The type species of both Ethusa and Ethusina ( Ethusa mascarone (Herbst, 1785) , and Ethusina abyssicola Smith, 1884 , respectively) are Atlantic in distribution and are therefore not represented among the Indo-West Pacific species listed here. A revision of the Ethusinae , which would encompass the examination of Atlantic and eastern Pacific species, is therefore beyond the scope of this investigation.