Three new Mediterranean Maera with remarks on the Quadrimana complex (Crustacea, Amphipoda, Melitidae)

Three new Mediterranean species of the Maera quadrimana complex are described and illustrated: Maera revelata from the western sector, M. ariadne from the eastern one and M. aurora from the entire Mediterranean. Maera inaequipes (A. Costa, 1857) is redescribed and its synonymy and geographical distribution are revised to stabilize the confused taxonomy of this species. These four species are compared by means of a table and an identification key. The Maera quadrimana complex is defined and 19 species are recognized in the world. This group is briefly reviewed from a biogeographical point of view.