Author(s): Anna Novichkova
Email (s): email@example.com
Institution or organization of origin: MSU, Severtsov Institution of Ecology and Evolution
Freshwater ecosystems of the Magadan district are one of the least studied among the territories of the North-East Russia. The zooplankton composition was studies in different shallow thermocarst lakes and temperate puddles. We found more than 50 taxa of microcrustaceans (Cladocera, Copepoda), some of them were new for the region, one was described as new to science. New for the Magadan district were six species of Copepoda: Eurytemora affinis affinis, Leptodiaptomus minutus, Eucyclops cf. ohtakai, Cyclops kolensis alaskaensis, Cyclops sibiricus, Bryocamptus (Arcticocamptus) arcticus. Of them E. affinis affinis has wide Holarctic area, B. arcticus is northern palearctic species. L. minutus, C. kolensis alaskaensis and Cyclops sibiricus (C. canadensis is probably subspecies of this species), are widespread in the northern territories of North America (including Alaska). E cf. ohtakai was described from the islands of the archipelago of Japan, and its presence in the Magadan district, after the verification, can become the northernmost point of its dispersion. Thus, freshwater copepods of the Magadan district consist a combination of Eurasian and North American faunas. The same holds for Cladocera. Together with widespread North Eurasian species there are some species, typical for the eastern part of Eurasia or North America, such as Ophryoxus kolymensis, Sida ortiva, Eurycercus (Eurycercus) macracanthus. Freshwater species with disjunctive areas from separated continents represent the relict fragments of the ancient Beringian fauna, disappeared with the transgression of the Pacific Ocean. The transient nature of the freshwater microcrustacean fauna of the Magadan district is a specific trait of this region.