Petrolisthes zacae Haig, 1968

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 : 122

Petrolisthes zacae Haig, 1968

( Figs. 76 , 77 )

Petrolisthes zacae Haig, 1968: 63 , fig. 2, tab. 1; Gore & Abele 1976: 25; Abele & Kim 1989: 22; Hiller et al. 2004: 132; Hiller et al. 2006: 554; Lazarus-Agudelo & Cantera-Kintz 2007: 230.

Material examined. None from Panama. Extra-limital material. Colombia [Pacific]: 1 male, cl 4.7, cw 4.2, 1 female, cl 5.9, cw 6.0 (CERBMcr-UV:2009-103), Bahía Málaga, La Sierpe, rocky intertidal near small waterfall, under rocks, leg. J.F. Lazarus-Agudelo, 25.04.2009 (fcn COL-151, COL-152) .

Previous records from Panama. Gore & Abele (1976); Gore (1982); Abele & Kim (1989).

Distribution. East Pacific: Costa Rica, Panama ( Panama Canal area) and Colombia ( Gore & Abele, 1976; Gore, 1982; Hiller et al., 2004).

Ecology. Largely intertidal; on exposed muddy banks of brackish mangrove swamps, dwelling in burrows and depressions in mud; also under rocks in muddy-rocky intertidal, close to waterfalls or creeks ( Gore & Abele 1976; Hiller et al. 2004; present study).

Remarks. Petrolisthes zacae is most closely related to P. robsonae , P. armatus and P. nobilii , sharing with them the carapace not transversely striate; the P1 carpus with teeth on mesial margin; and the P2–P4 meri dorsally armed with spines. According to the molecular analysis of Hiller et al. (2006), P. zacae is sister of P. robsonae , with the eastern Pacific and western Atlantic P. armatus representing in turn their sister clade. Petrolisthes zacae differs from P. robsonae , P. armatus and P. nobilii by the shape of the P2–P4 dactyli: long and slender, with a “thumblike” projection about halfway along ventral (lower) margin, tipped with a movable corneous spinule. This peculiar structure of the ambulatory dactylus is unique within Petrolisthes and likely represents some form of adaptation for living in muddy coditions, i.e. for walking on soft mud ( Haig 1968). The colour pattern of P. zacae ( Figs. 76 , 77 ) is illustrated for the first time.

Genus Pisidia Leach, 1820

Figures

FIGURE 76. Petrolisthes zacae Haig, 1968: A–C, extra-limital specimen, male (cl 4.7 mm, cw 4.2 mm) from Bahía Málaga, Colombia (CRBM-UV-cr:2009-103), dorsal (A), ventral (B) and frontal (C) views [photographs by AA].

FIGURE 77. Petrolisthes zacae Haig, 1968: A, B, extra-limital specimen, female (cl 5.9 mm, cw 6.0 mm) from Bahía Málaga, Colombia (CRBM-UV-cr:2009-103), dorsal (A) and frontal (B) views [photographs by AA].