Abstract
Studies on water mite evolution regarding the phylogenetic implication are reviewed. Hydracarina is a large parasitengone mite group. Currently, more than 5, 000 species are integrated into 52 families in nine superfamilies. Although there are some conflicts on the origin of water mites, their monophyletic nature is suggested by several cladistic studies. The current taxonomic system of water mites does not reflect monophyletic groupings. Some researches have focused on phylogenetic relationships within Hydracarina, however, reliable hypotheses have not been obtained. Attempts to analyze data in a phylogenetic framework have been made in several ecological and behavioral studies. A comparative method has also been employed in a few studies, however, the real worth of this approach is not appreciated due to the absence of reliable phylogeny. Phylogenetic background estimated by modern cladistic methodology is indispensable for testing hypotheses on water mite evolution.
