Petrolisthes occidentalis Stimpson, 1859

Ferreira, Luciane Augusto De Azevedo & Anker, Arthur, 2021, An annotated and illustrated checklist of the porcelain crabs of Panama (Decapoda: Anomura), Zootaxa 5045 (1), pp. 1-154 : 107

Petrolisthes occidentalis Stimpson, 1859

( Figs. 66 , 67 )

Petrolisthes occidentalis Stimpson 1858: 227 (nomen nudum); Stimpson 1859: 73; Hiller et al. 2006: 564, 565.

Petrolisthes galathinus . — Ortmann 1897: 283 (part.); Haig 1960: 36 (part.), pl. 19, fig. 4; Lazarus-Agudelo & Cantera-Kintz 2007: 230 [not Petrolisthes galathinus ( Bosc, 1802) ].

Petrolisthes galathinus EP. — Hiller et al. 2006: 553.

Material examined. Panama [ Pacific ]: 1 male, cl 6.7, cw 6.1 ( FLMNH UF 57156 ), Coiba Is., off eastern coast of Isla Coiba , Isla Granito de Oro , Mona Lisa submerged rock, 7°35’39.9”N, 81°42’45.3”W, depth less than 8 m, in dead Pocillopora heads, leg. M. Leray et al., 18.02.2019 (fcn PAN-049) ; 1 male, cl 14.3, cw 14.4 ( MZUSP 33451 ), Río Mar , rocky intertidal, under rocks and in rock crevices, leg. A. Anker, J.F. Lazarus-Agudelo & T. Kaji, 20.03.2015 ; 1 male, cl 12, cw 12.2 ( MZUSP 33452 ), same collection data as for previous specimen ; 1 male, cl 9.0, cw 8.9 ( MZUSP 33893 ), Las Perlas Is., small rocky island off northeast of Isla Saboga , depth at low tide 0–1.5 m, rocky-sandy bottom, under rocks on coarse sand, in dead and living corals, in rock crevices, leg. A. Anker, J. Luque, A.R. Palmer & T. Kaji, 22.04.2015 .

Previous records from Panama. Stimpson (1859); Haig (1960, as P. galathinus ); Gore & Abele (1976, as P. galathinus ); Abele & Kim (1989, as P. galathinus ).

Distribution. East Pacific: El Salvador, Nicaragua, Costa Rica, Panama (Coiba Is., Río Mar, Panama Canal area, Ciudad de Panamá, Taboga Is., Las Perlas Is.) and Ecuador ( Haig 1960; Abele & Kim 1989; present study).

Ecology. Intertidal and subtidal, known depth range: 0–20 m, probably deeper; on various sand, mixed sandshell and hard bottoms, under rocks and in rock crevices, in dead coral heads ( Pocillopora ) ( Haig 1960; present study).

Remarks. Petrolisthes occidentalis is an eastern Pacific member of the P. galathinus species complex (see above) and was for a long time considered to be a junior synonym of P. galathinus ( Haig 1960) . However, based on molecular and morphometric data, as well as some differences in the colour pattern, Hiller et al. (2006) recommended P. occidentalis to be reestablished as a valid species, a recommendation followed by the present authors. Petrolisthes occidentalis has a very consistent and diagnostic colour pattern, dominated by red and yellow colours ( Figs. 66 , 67 ), which seems to be different from all colour patterns observed in various western Atlantic populations of P. galathinus , some of them presumably representing cryptic or pseudocryptic species (see above).

Figures

FIGURE 66. Petrolisthes occidentalis (Bosc, 1802): A, B, male (cl 9.0 mm, cw 8.9 mm) from Las Perlas Islands, Panama (MZUSP 33893), dorsal (A) and ventral (B) views [photographs by AA].

FIGURE 67. Petrolisthes occidentalis (Bosc, 1802): A, B, male (cl cw indet.) from Taboga Island, Panama (not deposited), dorsal (A) and ventral (B) views [photographs by AA].