Pachycheles riisei (Stimpson, 1859)

(Fig. 2 B)

Pisosoma riisei Stimpson, 1858: 228 [nomen nudum]; 1859: 75 (type-locality: St. Thomas, Virgin Islands). Pachycheles riisei —Haig, 1956: 12.

Material examined. Brazil: Ceará—Acaraú, R/V “Almirante Saldanha”, st. 1710, 17 m, 1 ovigerous female (MZUSP-8981). Paraíba—Tambaú, Recife Quebra-Quilha, 1 male, 1 ovigerous female (MZUSP-13842). Pernambuco—Paulista, 2 ovigerous females (DOUFPE-7485). Alagoas—Marechal Deodoro, Praia do Francês, 1 ovigerous female (MZUSP-12577). São Paulo—São Sebastião, 2 males (MZUSP-10670).

Geographic distribution. Western Atlantic—USA, Florida; Belize, Carrie Bow Cay; Puerto Rico; Virgin Islands, St. Thomas; Barbados; Colombia, Gulf of Darien, Santa Marta, Providence and Rosario Islands; Venezuela, Margarita and Cubagua Islands; Tobago and Brazil (Rocas Attol, Fernando de Noronha and Trindade Islands, Ceará and from Paraíba to São Paulo).

Recognition characters. Carapace slightly broader than long, convex and smooth; posterolateral regions plicate; epibranchial region dilated. Front broad. Outer orbital angle produced into acute teeth. Chelipeds subequal; merus with subtriangular lobe on dorsoflexor margin, 2 small distal teeth on ventroflexor margin; carpus with 3 lamelar, sinuous lobes on flexor margin, extensor margin fairly rugose, with longitudinal groove delimitating carina, distal tooth; propodus with longitudinal groove delimitating carina on extensor margin; fingers with prominent proximal tubercle, grooved on cutting face; major cheliped with hiatus. Walking legs smooth; propodus with 4 spines on flexor margin; dactylus with 4 or 5 spines on flexor margin. No gonopods in males. Telson composed of 5 plates.

Habitat. Intertidal region, under rocks, on calcareous algae and coral reefs (Veloso 1998).