Petrolisthes occidentalis Stimpson 1859
Creators: name: Ferreira, Luciane Augusto De Azevedo
name: Anker, Arthur
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Porcellanidae
Petrolisthes
Petrolisthes occidentalis

description: 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).
description: Published as part of Ferreira, Luciane Augusto De Azevedo & Anker, Arthur, 2021, An annotated and illustrated checklist of the porcelain crabs of Panama (Decapoda: Anomura), pp. 1-154 in Zootaxa 5045 (1) on page 107, DOI: 10.11646/zootaxa.5045.1.1, http://zenodo.org/record/5532178