A new species of Pseudoniphargus (Crustacea, Amphipoda, Melitidae) from an anchialine cave on the French Mediterranean coast

A new species of the stygobiont melitid amphipod genus Pseudoniphargus Chevreux, 1901 is described from an anchialine cave located on the inner shore of the Salses-Leucate coastal lagoon, on the French Mediterranean coast. The new species is distinguished from other members of the genus by the combined display of: 1) gnathopod II not sexually dimorphic, with short carpus; 2) outline of basis of pereopods V-VII sexually dimorphic, with both margins convex and with overhanging posterodistal lobe in male, whereas margins subparallel and posterodistal lobe present but not overhanging in female; 3) uropod I protopod lacking basofacial robust seta; 4) protopod of uropod III sexually dimorphic, proportionaly more elongated in male; 5) exopod of male uropod III not strongly elongated (less than 12 times as long as wide), slightly upcurved and tapering; female exopod similar but shorter (about 8.8 times as long as wide); and 6) telson wider than long, with distal margin shallowly excavated and with two distal robust setae at each side. The relationships of this species are briefly discussed.