On Members of the Gammarus Pulex-Group (Crustacea-Amphipoda) from Western Europe

Abstract

The morphological diversity within the Gammarus pulex -group and the confusion concerning the systematic position of the various forms belonging to this group, already noticed by the author in 1970, formed the reason to give detailed descriptions of the different forms in this group and to discuss the variability within these forms. Hybridization experiments have been run between various morphologically different populations, closely related to, or intermediate between G. pulex and G. wautieri from different localities in Western Europe. The results of these experiments, have an implication to the systematic position of these different populations. When available, information is given on the ecology and distribution of the various species.