Salinalona gen. nov., an euryhaline chydorid lineage (Crustacea: Branchiopoda: Cladocera: Anomopoda) from the Oriental region

Until now, a single endemic cladoceran genus was known from the Oriental region. We propose the region’s second endemic lineage of generic rank, <em>Salinalona</em> gen. nov., to accomodate the South East Asian <em>Alona sarasinorum </em>Stingelin, 1900 and the Indian <em>A. taraporevalae</em> Shirgur and Naik, 1977. Morphological revision shows that the external similarities with <em>Alona</em> Baird, 1843 or <em>Leberis</em> Smirnov, 1969 and <em>Celsinotum</em> Frey, 1991 that have been proposed in the past, are the result of convergence. The small lineage is euryhaline, even halophylic, an unusual adaptation in the order Anomopoda and particularly in the family Chydoridae. We discuss the position and adaptation of <em>Salinalona</em> gen. nov., such as a strongly modified hook on the first limb, based on a detailed study of populations from Maikhao peat swamp, Phuket island, Thailand. We include comparative notes on the circumtropical genus <em>Euryalona </em>Sars, 1901, with detailed morphology of the Asian <em>E. orientalis </em>(Daday, 1898). A key to all species of both genera is included.