Chydoridae is a family of water fleas in the order Anomopoda. There are more than 50 genera and 520 described species in Chydoridae. A lot of Chydoridae species are non-native species, many of which pose a great threat to aquatic ecosystems.
Genera These 52 genera belong to the family Chydoridae:
Acroperus Baird, 1843 Alona Baird, 1850 Alonella G. O. Sars, 1862 Alonopsis G. O. Sars, 1862 Alpinalona Alonso & Sinev, 2017 Anchistropus G. O. Sars, 1862 Anthalona van Damme, Sinev & Dumont, 2011 Archepleuroxus Smirnov & Timms, 1983 Armatalona Sinev, 2004 Australochydorus Smirnov & Timms, 1983 Biapertura Smirnov, 1971 Bryospilus Frey, 1980 Camptocercus Baird, 1843 Celsinotum Frey, 1991 Chydorus Leach, 1816 Coronatella Dybowski & Grochowski, 1894 Dadaya G. O. Sars, 1901 Disparalona Fryer, 1968 Dumontiellus Smirnov, 2007 Dunhevedia King, 1853 Ephemeroporus Frey, 1982 Ephmeroporus Euryalona G. O. Sars, 1901 Eurycercus Baird, 1843 Extremalona Sinev & Shiel, 2012 Geoffreya Kotov, Sinev & Berrios, 2010 Graptoleberis G. O. Sars, 1862 Indialona Petkovski, 1966 Karualona Dumont and Silva-Briano, 2000 Kisakiellus Sousa & Elmoor-Loureiro, 2018 Kurzia Dybowski and Grochowski, 1894 Leberis Smirnov, 1989 Leydigia Kurtz, 1874 Maraura Sinev & Shiel, 2008 Matralona van Damme & Dumont, 2009 Miralona Sinev, 2004 Monope Smirnov & Timms, 1983 Monospilus G. O. Sars, 1861 Notoalona Rajapaksa and Fernando, 1987 Ovalona van Damme & Dumont, 2008 Oxyurella Dybowski and Grochowski, 1894 Paralona Sramek-Husek, Straskraba and Brtek, 1962 Parvalona Van Damme, Kotov & Dumont, 2005 Peracantha Baird, 1843 Picripleuroxus Frey, 1993 Pleuroxus Baird, 1843 Pseudochydorus Fryer, 1968 Rak Smirnov & Timms, 1983 Rheoalona Sinev, Tiang-Nga & Sanoamuang, 2017 Rhynchochydorus Smirnov & Timms, 1983 Rhynchotalona Norman, 1903 Saycia Sars, 1904 Tretocephala D.G.Frey, 1965
Evolution and biogeography
The family Chydoridae has served as a primary model for rejecting the concept of cosmopolitanism (the "everything is everywhere" hypothesis) in microscopic freshwater animals. Early comprehensive morphological revisions by D.G. Frey demonstrated that supposedly widespread chydorid taxa are actually complexes of species with restricted, often endemic, distributions.
Modern molecular phylogeography has strongly supported and expanded this paradigm. Integrative taxonomic studies have revealed deep cryptic diversity within morphologically uniform taxa, indicating that many "widely distributed" species are actually complexes of ancient lineages. For example, phylogeographic analysis of the Chydorus sphaericus species complex in the Northern Palearctic identified multiple distinct clades that survived Pleistocene glaciations in separate refugia (e.g., in Europe and Beringia). The Yenisey River basin in central Eurasia was identified as a "suture zone" where these previously isolated European and Beringian lineages came into secondary contact.
Similarly, recent multilocus studies on the Pleuroxus genus have demonstrated general morphological stasis, where deeply divergent genetic lineages (separated by millions of years) remain morphologically almost indistinguishable. The Eurasian Pleuroxus aduncus species group was found to be paraphyletic, containing a cryptic Siberian species (Pleuroxus korovchinskyi) and giving rise to the highly derived, denticulated Pleuroxus truncatus. These findings highlight the complex historical biogeography of chydorids and underscore the necessity of continued integrative taxonomic revisions of cladoceran taxa.
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Further reading