Petrolisthes armatus (Gibbes, 1850) (Fig. 2 E) Porcellana armata Gibbes, 1850: 190 (type-locality: Florida, USA). Petrolisthes armatus —Stimpson, 1858: 227. Petrolisthes marginatus— Nobili, 1897: 4 [non P. marginatus Stimpson]. Petrolisthes lamarcki —Moreira, 1901: 33, 91 [non P. lamarcki Leach]. Non P. armatus —Boone, 1930: 73, pl. 19; 1931: 151, fig. 6; 1935: 53 [= P. nobilii Haig, 1960]. Material examined. Mexico: Gulf of California, Quintana Roo, San Felipe, 1 male (MZUSP-9473). Brazil: Pará— Ilha de Fortaleza, 4 males, 2 females, 1 ovigerous female (MNRJ -735). Maranhão—Ilha do Rosário, 4 males, 1 female, 1 ovigerous female (MNRJ-3790). Ceará—Aracati, Praia do Retiro Grande, 2 males, 3 ovigerous females (MNRJ- 740). Pernambuco—Recife, Recife da Piedade, 1 ovigerous female (MZUSP-7536). Bahia—Itaparica, Coroa de Pedra, 1 female (MNRJ-8726); Ilhéus, 1 male, 1 female (MZUSP-19530). Espírito Santo—Anchieta, Praia de Anchieta, 9 males, 3 females, 3 ovigerous females (MZUSP-7000). Rio de Janeiro—Ilha Grande, 4 males, 1 female, 2 ovigerous females (MZUSP-591); Niterói, Muriqui, 1 male, 1 female (MNRJ-746). São Paulo— Ilhabela, Praia Engenho D’água, 2 males, 10 females (MZUSP-19559). Paraná—Paranaguá, Ilha do Mel, Praia do Encantado, 11 males, 8 females (MZUSP-9023); Cabaraquara, 34 males, 15 females, 1 ovigerous female (MZUSP- 20173). Santa Catarina—Palhoça, Enseada do Brito, 1 male (MZUSP-6956). Recognition characters. Carapace slightly longer than broad, flattened, transversely rugose mainly on branchial regions; epibranchial spine. Front broad, serrate. Merus of antenna with strong subtriangular and serrate lobe on mesial margin, usually spine-tipped. Chelipeds subequal, flattened and rugose; carpus with 3 acute, sometimes spine-tipped teeth on flexor margin, row of spines on extensor margin; propodus usually fringed with plumose setae on proximal third of extensor margin; gape of fingers heavily pubescent. Walking legs pubescent; merus with row of spines on extensor margin, propodus with 4 spines on flexor margin; dactylus with 3 spines on flexor margin. Gonopods present in males. Telson composed of 7 plates. Habitat. Euryhaline species that inhabits mangal regions, where lives at root branches of Rhizophora sp. and Avicenia sp., and in small lagoons. Also found on intertidal region, under rocks, on corals, sponges, reefs built by Phragmatopoma lapidosa, mussel beds and oysters, and seems to prefer calm waters (Werding 1977; Veloso & Melo 1993; Micheletti-Flores & Negreiros-Fransozo 1999) down to 60 m. Geographic distribution. Western Atlantic—USA, Connecticut, North Carolina, Georgia, eastern and western Florida, Louisiana, Texas; Bermuda; Mexico, Tamaulipas, Veracruz, Campeche and Quintana Roo; Belize; Costa Rica, Gulf of Nicoya; Panama, Bocas del Toro, Colón and Caledonia Bay; Bermuda; Bahamas; Cuba; Jamaica; Puerto Rico; Virgin Islands; Colombia, Punta Calixto and Rosario Island; Venezuela, Curacao, Blanquilla, Cubagua and Margarita Islands; and Brazil (Fernando de Noronha Island and from Pará to Santa Catarina). Eastern Atlantic—Ascensão Island; Gibraltar; Senegal and Angola. Eastern Pacific—from Gulf of California to Ecuador (Galapagos Islands); and Peru. Variation. Populations of different localities have shown considerable intraspecific morphological variation. Basically, the palm of the cheliped varies from narrow to broad and a row of spines and setae on extensor margin of propodus may be present or absent. Besides, the number of flexor teeth on the cheliped carpus varies from 1 to 4.

Published as part of Ferreira, Luciane Augusto De Azevedo & Melo, Gustavo Augusto Schmidt De, 2016, Porcelain crabs from Brazil (Crustacea: Decapoda: Anomura: Porcellanidae), pp. 175-194 in Zootaxa 4092 (2) on pages 185-186, DOI: 10.11646/zootaxa.4092.2.2, http://zenodo.org/record/261197