Petrolisthes galathinus Bosc 1802

Petrolisthes galathinus (Bosc, 1802)

(Fig. 2 F)

Porcellana galathina Bosc, 1802: 233, plate 6, figure 2 (type-locality: unknown). Porcellata sexspinosa Gibbes, 1850: 190.

Petrolisthes sexspinosus Stimpson, 1858: 227.

Petrolisthes galathinus —Ortmann, 1897: 283.

Material examined. Brazil: Rio Grande do Norte—Barra Formosa, Cabo do Baco-Pari, 1 male, 1 female (MZUSP-7176). Paraíba—Ponta dos Seixas, 1 male (MZUSP-15528). Pernambuco—Recife, Praia do Pina, 4 males, 1 female (MNRJ-13536). Alagoas—Passo de Camaragibe, 2 males, 3 females (LabMar-516). Sergipe— Aracaju, Atalaia Velha, 1 male (MNRJ-1410). Bahia—Itaparica, 1 female (MZUSP-7175). Espírito Santo— Aracruz, 1 female (MZUSP-18743). Rio de Janeiro—Búzios, Praia de Manguinhos, 2 males (MZUSP-18710). São Paulo—Ilha Vitória, 1 male (MZUSP-586); Ubatuba, Pedra do Morcego, 2 males, 1 ovigerous female (MZUSP- 11303); Santa Catarina—Bombinhas, Ponta das Garoupas, 2 females, 1 ovigerous female (MNRJ-3812).

Recognition characters. Carapace as long as broad, covered with strong transverse, piliferous rugae interrupted at grooves separating regions; strong epibranchial spine; frontal region slightly granulate. Outer orbital angle produced into spine-tipped tooth; inner orbital angle produced into acute spine. Chelipeds with strong piliferous rugae; ischium with subdistal spine on flexor margin, proximal spine on ventro-extensor margin; merus with serrate-edged, distal spine-tipped tooth on flexor margin, 2 or 3 distal spines on extensor margin, subproximal spine on dorso-extensor margin, flexor margin with 2 ventrodistal spines; carpus with 4 serrate-edged, spine-tipped teeth on flexor margin, row of spines and setae on extensor margin, distal spine at articulation of propodus; propodus fringed with plumose setae and row of spines on extensor margin. Walking legs rugose, pubescent; merus with row of spines on extensor margin, propodus with 5 spines on flexor margin, dactylus with 3 spines on flexor margin. Gonopods present in males. Telson composed of 7 plates.

Habitat. Under rocks and associated with sponges, corals and anemones on littoral; in benches of shells at tide pools and intertidal regions, on calcareous algae bottoms, occasionally on sand; down to depths of 54 m (Ramos- Porto et al. 1978; Williams 1984). It may also be found among roots of mangroves, conglomerates of Mytillus sp., clusters of polychaetes and in Porites interstices (Werding 1982; Veloso & Melo 1993).

Geographic distribution. Western Atlantic—USA, North and South Carolina, Florida, Texas; Mexico, Tamaulipas, Veracruz, Campeche, Yucatan and Quintana Roo; Belize, Carrie Bow Cay; Panama, Bocas del Toro, Colón and Caledonia Bay; Aruba; Curacao and Bonaire; Cuba; Jamaica; Puerto Rico; Virgin Islands, St. Thomas; Barbados; Colombia, Providence, Rosario and Santa Marta Islands; Venezuela, Los Roques, Margarita and Cubagua Islands; Trinidad; Suriname; French Guyana and Brazil (Trindade Island and from Pará to São Paulo and Santa Catarina). Eastern Pacific—El Salvador; Nicaragua, Estero Asserradores; Costa Rica, San Lucas Island; Panama, Tobaguilla Island, Limón Bay and Panama City; and Ecuador, La Liberdad.

Variation. Considerable color variations have been reported for Petrolisthes galathinus by several authors (e.g., Benedict 1901; Rickner 1975; Abele & Kim 1989; Williams 1984). Werding (1977) was the first author to recognize the presence of different forms in the western Atlantic which were morphologically very similar but distinguishable by the detailed color pattern. These findings lead the author to describe P. rosariensis Werding, 1978, P. c ar i be n s i s Werding, 1983 and P. columbiensis Werding, 1983, and referred these species to the “ P. galathinus complex”. Later, material of two additional color forms from the Caribbean coast of Colombia are described as P. sanmartini Werding & Hiller, 2002 and P. bolivarensis Werding & Kraus, 2002. Currently, the “ P. galathinus species complex” consists of these six species which are morphologically distinguished by a combination of discrete differences, such as colour pattern, epibranchial spine, number of spines on the dactylus of walking legs and pubescence in the gape of cheliped fingers.

Remarks. Bosc (1802) originally described Petrolisthes galathinus (as Porcellana), but did not designated neither a type-specimen nor a type-locality. Gibbes (1854) suggested that the original material must have been from the southern Atlantic coast of USA.