BIOCHEMICAL SYSTEMATIC RELATIONSHIPS AMONG THE FRESH-WATER AMPHIPODS GAMMARUS-VARSOVIENSIS, GAMMARUS-LACUSTRIS AND GAMMARUS-PULEX

The systematic position of the freshwater amphipod G. varsoviensis Jaz dzewski from northern Poland and Germany, split off recently from G. l acustris Sars in the same area, was assessed by allozyme electrophores is. A distant evolutionary relationship between the two species was in dicated, similar to that between them and G. pulex (L.), and to those earlier recorded between marine and freshwater Gammarus spp. (genetic identities I = 0.1-0.2). The neutral terms currently used for subdivis ions of the genus, such as the G. pulex group which includes the three species studied, refer to units too ancient to have retained traces o f a common ancestry at the allozyme level; adoption of subdivisions ba sed on phylogenetically closer, genetically identifiable relationships is suggested.