The genus Platorchestia (Crustacea, Amphipoda) on the Mid-Atlantic islands, with description of a new species from Saint Helena

Abstract

Landhoppers (Crustacea, Amphipoda, Talitridae) of the genus Platorchestia from various Mid-Atlantic islands (Azores, Madeira, Ascension, Saint Helena) and from continental Europe have been compared. They belong to three sibling species: P. platensis (Krnyer, 1845) from temperate, near-shore areas, P. rnonodi (Mateus et al., 1986) from warm-temperate and (sub)tropical, often inland, places, and P. ashrnoleorurn n. sp. from the low-altitude zones of St. Helena. The subtle differences between the sibling species are described and illustrated.