Petrolisthes artifrons Haig 1960

Petrolisthes artifrons Haig, 1960

Petrolisthes artifrons Haig, 1960: 27, 119, pl. 22: fig 4; Gore 1982: 12; Werding & Haig 1982: 66; Moran 1984: 78.

Material examined. None.

Previous records from Panama. Gore (1982).

Distribution. East Pacific: El Salvador, Costa Rica, Panama (Ciudad de Panamá, including Amador Causeway, Isla Otoque, Punta Guayabo Chiquito in Darién), Colombia and Ecuador (Haig 1960; Gore 1982; Moran 1984).

Ecology. Intertidal and subtidal, presently known depth range: 0–20 m; under rocks and on sandy and shell bottom (Haig 1960; Gore 1982), also in crevices of intertidal “arenaceous worm tubes” (Moran 1984).

Remarks. Petrolisthes artifrons is allied to P. crenulatus Lockington, 1878 P. ortmanni Nobili, 1901, P. hians Nobili, 1901, P. lewisi (Glassell, 1936) and P. cocoensis Haig, 1960, but can be readily distinguished from all of them by a narrower, more produced and less deflexed front of the carapace (Haig 1960). This uncommon species appears to have the same distributional range as P. lewisi and the two species may occur together in the same habitats (Haig 1960; Gore 1982). Gore (1982) separated P. artifrons from P. lewisi by: (1) the P1 carpus with granulation less pronounced and furrows rather shallow (vs. granulation and furrows more distinct in P. lewisi); (2) the rugae on the P1 much less developed; (3) the posterior margin of the P1 carpus rounded (vs. nearly straight in P. lewisi); and (4) the proximal margin of the P1 carpus irregularly subdivided into a two-toothed lobe mesially (vs. distinctly and more evenly bi- or tridentate in P. lewisi).