PSYCHODROMUS-BETHARRAMI N-SP (CRUSTACEA, OSTRACODA) - MORPHOLOGY, ECOLOGY AND BIOGEOGRAPHY

A new freshwater ostracode species, Psychrodromus betharrami n. sp., i s here described using material collected from several localities in t he Mediterranean area. Morphological differences with the closely rela ted species Psychrodromus fontinalis (Wolf) proved to be subtle but co nstant in all populations examined. Males from northern Italy original ly assigned to P. fonttinalis by Fox (British Museum) are redescribed and placed in P. betharrami n. sp. Both species are compared with the more generalist and widely distributed Psychrodromus olivaceus (Br. & N.) and their ecomorphological adaptations to live in the transition b etween epigean and hypogean environments are stressed. Additional info rmation on the ecology and biogeography of the species in the genus is provided, and an hypothetical evolutionary scenario discussed.