Large branchiopods are part of the Branchiopoda (gillfoot) class of crustaceans. They are thought to be among the most ancient living animals, and they are the largest representatives of the zooplankton of temporary ponds. Romania has the largest documented species number of this group in Europe (26 species). Russia has probably some more, but this is not well documented. dr. Erich Eder has a nice web page about these fascinating animals at www.urzeitkrebse.at These are green fairy shrimps (Chirocephalus shadini) And these are spring fairy shrimps (Tanymastix stagnalis) from an extinct population since the making of the picture