Senecella siberica n. sp. and the position of the genus Senecella in Calanoida classification

Senecella calanoides Juday has been reported from fresh-water lakes of North America, Northern Siberia and inshore brackish waters of Kara and Laptev Seas. Investigation of 11 females and 2 males from the brackish waters of Neelov Bay (Laptev Sea) shows that second species, Senecella siberica sp. n., can be distinguished from S. Calanoides Juday by the greater size, a slightly asymmetrical female genital segment, the 3 external spines on the 3d exopod of 2 to 4th swimming legs and by more longer left endopod digitiform process of the male 5th legs. S. siberica seems to be brackish-water euryhaline species, inhabiting brackish waters with salinity from 1 to 22. The genus belongs to the family Aetideidae and is the only genus with freshwater representatives.