A revision of the European species of the Echinogammarus pungens-group (Crustacea, Amphipoda)

A revision of the species belonging to the group of, or confused with “Gammarus” (now Echinogammarus) pungens H. Milne Edwards, 1840 is given. Not less than 7 species have, at one or more occasions, been confused with E. pungens. All of these, and a number of related forms, are described and illustrated in detail, in several cases after consultation of the original or of the type material. In order to stabilize the nomenclature of this group, a neotype is selected to replace the lost types of Gammarus pungens. A key to the species is provided. The subgenera Homoeogammarus and Parhomoeogammarus, as well as the genus Ostiogammarus, are synonymized with Echinogammarus. The subgenus, or genus, Marinogammarus is synonymized with Chaetogammarus. Since the species known as Gammarus or Marinogammarus olivii (now Chaetogammarus olivii) is frequently confused with various Echinogammarus species, this species and some of its allies are included as well in the present paper. The variability and ecological preferences of each species are discussed