A new species of Petrolisthes (Crustacea, Anomura, Porcellanidae) inhabiting vermetid formations (Mollusca, Gastropoda, Vermetidae) in the southern Caribbean Sea

: Petrolisthes virgiliussp. nov. from the Caribbean Sea of Colombia is described. The new species resembles P. tonsorius morphologically but differs from it principally by its color and habitat. Petrolisthes tonsorius is brown or blueish brown and occurs under intertidal boulders strongly exposed to water movement. Petrolisthes virgiliussp. nov. is pale brown to beige and lives exclusively in intertidal areas dominated by vermetid snails, exposed to heavy wave action. The entangled tubular shells of vermetids are cemented to each other and to a hard substrate like beach rock, forming a microhabitat for the new crab species and other porcellanids of the genera Neopisosoma and Clastotoechus. Large genetic distances between DNA sequences of the mitochondrial 16S rDNA gene from P. virgiliussp. nov. and P. tonsorius confirmed that they comprise different species. Petrolisthes virgiliussp. nov. is the 53rd member of the West Atlantic porcellanid fauna.