A new species of Pachycheles (Crustacea: Anomura: Porcellanidae), with taxonomic remarks on two other porcelain crabs from the remote oceanic archipelago of Trindade and Martin Vaz, South Atlantic Ocean

Abstract

Three species in two genera of porcelain crabs are reported from the remote oceanic archipelago of Trindade and Martin Vaz one of which, Pachycheles meloi, new to science. The new species is morphologically similar to Pachycheles riisei (Stimpson, 1858) from the inner continental shelf between Florida (USA) and São Paulo (Brazil), of which Pachycheles meloi sp. nov. differs by a suite of carapace and appendage characters, including the presence of a pair of male gonopods on the second abdominal segment (absent in P. riisei). The new species is additionally compared to other congeners. Opportunity is taken to elaborate on the taxonomy of Petrolisthes amoenus (Guérin-Méneville, 1855) and Petrolisthes marginatus (Stimpson, 1859). The Trindade and Martin Vaz Archipelago contain a strongly depauperate porcellanid fauna of western Atlantic affinities.