Prionalpheus gomezi Martinez-Iglesias & Carvacho 1991

Prionalpheus gomezi Martínez-Iglesias & Carvacho, 1991

(Fig. 11 C, D)

Prionalpheus gomezi Martínez-Iglesias & Carvacho 1991: 85, figs. 1, 2; Anker & De Grave 2012b: 1, figs. 1, 2.

Material examined. Brazil: 1 male, MZUSP 33407, Trindade Island, Enseada dos Portugueses, Praia da Calheta, 20°30’18.7”S – 29°18’31.6”W, depth: 9.9 m, coll. J.B. Mendonça, 26.x.2014; 1 male (?), MZUSP 31068, Trindade Island, Enseada dos Portugueses, Praia da Calheta in front of SECON, 20°30’20.9”S – 29°18’43.7”W, depth: 12.2 m, coll. J.B. Mendonça, 18.vii.2013; 1 female, MZUSP 31080, Trindade Island, Enseada dos Portugueses, Farol, 20°31’22.4”S – 29°19’52.0”W, depth: 14.6 m, coll. J.B. Mendonça, 10.vii.2012; 1 ovig. female, MZUSP 33360, Trindade Island, Enseada dos Portugueses, Farol, 20°29’52.3”S – 29°19’15.6”W, depth: 13.7 m, among algae, coll. J.B. Mendonça, 22.iv.2014; 1 ovig. female, MZUSP 33266, Trindade Island, Enseada dos Portugueses, Farol, 20°29’52.3”S – 29°19’15.6”W, depth: 13.7 m, coll. J.B. Mendonça, 22.iv.2014; 1 male, MZUSP 34117, Trindade Island, Enseada dos Portugueses, Farol, 20°29’52.3”S – 29°19’15.6”W, depth: 12.6 m, coll. J.B. Mendonça, 06.vii.2015; 1 male, 1 ovig. female, MZUSP 31072, Trindade Island, Paredão, 20°31’36.9”S – 29°18’14.3”W, depth: 19 m, coll. J.B. Mendonça, 19.vi.2012; 1 ovig. female, MZUSP 30293, Trindade Island, Enseada da Cachoeira, Farrilhões, 20°31’22.4”S – 29°19’52.0”W, depth: 17.9 m, coll. J.B. Mendonça, 04.vii.2012; 1 male, MZUSP 33309, Trindade Island, Enseada do Príncipe, Ilha Sul, 20°31’34.3”S – 29°19’27.9”W, depth: 17.6 m, coll. J.B. Mendonça, 06.xi.2014. Size of largest male: cl 1.8 mm (MZUSP 33407); largest female: cl 2.1 mm (MZUSP 33266).

Additional (extra-limital) material examined. Cayman Islands: 2 males, 1 female (all specimens missing chelipeds), FLMNH UF 41695, Little Cayman Island, eastern end, Owen Island, Heard-Sta4C, coll. R. Heard, 24.v.1995.

Description. See Martínez-Iglesias & Carvacho (1991) for original description and illustrations, and Anker & De Grave (2012b) for redescription and complementary figures.

Distribution. Western Atlantic: Caribbean Sea: Belize, Honduras, Cuba, Cayman Islands, Guadeloupe; Brazil: Trindade Island (Anker & De Grave 2012b; present study).

Ecology. Coral reefs and adjacent habitats with abundance of coral rubble or coralline algae; usually dwelling deep in crevices of coral or coralline rocks; intertidal to about 30 m.

Remarks. The present material represents the first record of Prionalpheus gomezi and the genus Prionalpheus for Brazil and the southwestern Atlantic. The species was previously known only from a few localities in the Caribbean Sea, where it appears to be quite uncommon, or at least is rarely seen (Anker & De Grave 2012b). The abundance of the material from Trindade Island shows that P. gomezi is common around the island, but because of its small size (carapace length of adults less than 3 mm) it may be collected only by a careful extraction of all small crustacean fauna associated with crevices in coralline rocks.

Prionalpheus gomezi is currently the only species of the almost pantropical genus Prionalpheus known to occur in the Atlantic Ocean. It differs from the other species of the genus, in addition to some morphological features, by a very distinctive colour pattern (Anker & De Grave 2012b: fig. 2; see also Fig. 11 C, D).