Polyonyx gibbesi Haig, 1956

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 : 127

Polyonyx gibbesi Haig, 1956

Porcellana macrocheles Gibbes 1850: 191 ; Gibbes 1854: 6, pl. 1, fig. 5 [Not Porcellana macrocheles Poeppig, 1836 ].

Polyonyx macrocheles . — Stimpson 1858: 229; Schmitt 1935: 189 [Not Porcellana macrocheles Poeppig, 1836 ].

Polyonyx gibbesi Haig 1956: 28 ; Williams 1984: 244, fig. 179; Rodríguez et al. 2005: 568; Ferreira & Melo 2016: 189 , fig. 3B; Diez & Lira 2017: 447 ; Poupin 2018: 151; Mantelatto et al. 2021: 571 .

Material examined. None.

Previous records from Panama. Haig (1956).

Distribution. West Atlantic: USA (Texas to Massachusetts), Cuba, Puerto Rico, S Lesser Antilles, Panama (Bahía de Caledonia), Venezuela, Brazil, Uruguay and Argentina ( Rodríguez et al., 2005; Ferreira & Melo 2016; Mantelatto et al. 2021).

Ecology. Intertidal and subtidal, known depth range: 0–47 m; on rocky, sandy and muddy bottoms, associated with the large parchment worm Chaetopterus variopedatus (Renier) , typically living in pairs inside the spacious tubes of the host ( Williams 1984; Ferreira & Melo 2016).

Remarks. Polyonyx gibbesi Haig, 1956 is the only species of the genus Polyonyx that occurs in the western Atlantic ( Rodríguez et al., 2005), where it has a vast distributional range, ranging from Massachusetts, USA, to Mar del Plata, Argentina and throughout the Gulf of Mexico and Caribbean Sea ( Ferreira & Melo 2016). The species seems to be relatively common in suitable habitats in the south-eastern USA and along the Atlantic coast of South America, and much less common in the southern Caribbean Sea. For instance, it is presently known from Panama based on a single male specimen from Bahía de Caledonia (collected at a depth of 2–14 m) reported by Haig (1956). A combined phylogeographic / morphological analysis of P. gibbesi is needed to investigate whether all western Atlantic populations actually form a single species. Living crabs are greyish white, sometimes stained with brown ( Williams 1984).