A new species of Pseudoniphargus (Crustacea, Amphipoda) from subterranean water of northeastern Morocco: Historical biogeography and evolutionary aspects

A new species of Pseudoniphargus, P. longiflagellum (Crustacea, Amphipoda) is described from subterranean fresh water of the Riftan region of Morocco. This species is closely related to the group P. ruffoi-P. longipes, which shares several apomorphic characters. The two-step model of colonization and evolution provides an understanding of the origin and the age of this stygobiont. P. longiflagellum is derived from marine ancestors that lived in the coastal groundwater of the Tethyan South-Rifian channel during the Miocene Tortonian period. The regression of this corridor during the late Tortonian period or at the beginning of the Messinian period may have played a major role in the evolutionary history through vicariance.