The genus Pseudoniphargus has long been considered monospecific. Its unique species, Ps. africanus, was supposed to occur on both sides of the Mediterranean, on the Atlantic side of the Iberian peninsula, on the Azores, and on Madeira, in localities ranging from the sea shore to more than 1000 m of altitude, and covering almost the entire natural salinity range (0-36‰). A taxonomie revision revealed that at least nine named species and several unnamed forms (of which insufficient material is available) hide under the name Ps. africanus, each with a narrow ecological and geographical range. The evolutionary scenario of the members of the genus is discussed at some length: they are presumably of marine origin, and got adapted to conditions of continental waters during various marine regressions in the Eocene and Oligocène, but notably in the Miocene.