: Diaptomus castor.

Diaptomus castor is the largest among diaptomid species in Norway. It is only recorded in a few sites in the vicinity of Oslo, but since it is a winter form with diapause in summer, it may have been overlooked and be more common.

Diaptomus castor (Jurine, 1820)
Creative Commons Attribution | Bjørn Walseng | Norsk institutt for naturforskning
Kart. Utbredelse i Norge.