Species richness and distribution of hermit crabs of the family Diogenidae (Crustacea: Decapoda: Anomura) in the eastern Pacific

Abstract

Based on a thorough revision of the Diogenidae (Crustacea: Decapoda: Anomura) of the eastern Pacific, 55 species belonging to 11 genera are reported from the region. Species of Paguristes are by far the most abundant (22 species, 40%). As a group, they are found from the intertidal to the upper slope (460 m), in virtually all habitats, with a significant proportion of species (47%) found from the intertidal to 20 m depth. The vast majority of species (93%) shows a clear tropical-subtropical affinity. Only seven species occur in the northern temperate subregion and seven in the southern temperate subregion. The majority of species (51) is typical of the eastern tropical Pacific or has at least one record in this subregion. The degree of endemicity is particularly high (36%) in the Cortes Province, but this figure is probably linked to a lack of comprehensive studies of the group in Central and South America. Nine species have been recorded from at least one oceanic island of the eastern Pacific, with a maximum of six in the Galapagos. Calcinus explorator is the most widely distributed species among the islands.