Redescription of Alona labrosa Vasiljeva & Smirnov, 1969 (Chydoridae, Anomopoda, Branchiopoda)

The morphology of the Baikalian Alona labrosa Vasiljeva & Smirnov, 1969 (Ch ydoridae, Anomopoda, Branchiopoda) is redescribed, based on the type and on new material. A. labrosa is a remarkable species that shows many traits wh ich are unique or rarely observed in Alona, and are a mix of primitive and advanced characters. A close relationship between A. labrosa and the ground water species A. phreatica Dumont, 1983 was revealed. It is probable that t hese two species, possible together with some other, will need to be alloca ted into a subgenus or even genus in the future. However, more detailed inv estigations of other marginal species of Alona are necessary for understand ing the position of A. labrosa among Aloninae.