Daphnia O. F. Müller, 1785 (Crustacea: Branchiopoda: Anomopoda) species of Iran: Morphology and Identification

Daphnia a wide spread member of Cladocera live in different aquatic environments ranging from hypersaline swamps to freshwater lakes, lagoons, streams and rivers. To improve our knowledge in the diversity of the genus Daphnia in Iran, and promoting its biogeographical information in the region, an investigation on the morphology and identification of the Iranian species of the genus was carried out during the spring of 2013 and 2014. The Southern Caspian Sea Basin (SCSB) and Urmia Lake Basin (ULB) Daphnia fauna has been studied based on historical literature records and new collections. Zooplanktons were sampled from 70 randomly chosen localities across ca. 2500 km wide longitudinal gradient in the SCSB and ULB basins including both permanent habitats (lakes and reservoirs), and small temporary water bodies (ponds and lagoons), both freshwater and saline. In the samples, 34 populations were identified based on the morphological and scanning electron microscopy (SEM) approaches. Cladistic analysis of Iranian species of genus Daphnia, based on 64 morphological characters obtained from the literature, confirmed the traditionally basic division of the genus into two subgenera, Daphnia and Ctenodaphnia. This split was supported by enough number of synapomorphies in the cladistic analysis. The relationships between all taxa within both subgenera were determined clearly. Cladistic analyses is a powerful tool to phylogenetic studies especially when more characters are defined and character states determined carefully. Finally, regional identification key for ten Iranian species of the genus Daphnia was provided.