Ecological and morphological characteristics of Daphnia O. F. Müller, 1785 (Crustacea,Cladocera) genus in Ukrainian Roztochia

Daphnia is a genus of small, aquatic, crustaceans, belonging to the Daphniidae fa­mi­ly. Daphnia are important components of freshwater food chains. They consuming algae and other small organisms, and in turn being prey for small fish and other carnivorous aquatic animals. Daphnia species are highly polymorphic and are an important component of the zooplankton. 1 548 tests in 1992–2012 in Ukrainian Roztochchya natural region were conducted. 750 species of Daphnia genus were studied. On the basis of ana­lysis of modern literature and own data ecological and morphological cha­racteristics of Daphnia genus and modern systematisation of species of Daphnia genus are presented. 6 species of Daphnia: Daphnia ( Daphnia ) pulex Leydig, 1860; Daphnia ( Daphnia ) longispina (O. F. Müller, 1776); Daphnia ( Daphnia ) hyalina Leydig, 1860; Daphnia ( Daphnia ) cucullata Sars, 1862; Daphnia ( Ctenodaphnia ) magna Straus, 1820; Daphnia ( Ctenodaphnia ) carinata King, 1853 were found. The species of Daphnia belonging to 2 subgenus ( Daphnia and Ctenodaphnia ) and 3 group of species ( Daphnia ( Daphnia ) pulex, Daphnia ( Daphnia ) longispina, Daphnia ( Ctenodaphnia ) similis ) have been defined. Keywords: Daphnia, zooplankton, Cladocera , Ukrainian Roztochya.