The biodiversity of Neotropical water mites

Abstract

The first studies on water mites from Central and South America date back to the 1880s, and although 1,360 species in 173 genera have been recorded so far, our knowledge of the diversity of this group in the Neotropic is rather incomplete. In order to estimate the total number of water mite species in this faunal region, I surveyed the state of the art in the exploration of neotropical water mites. The survey was based on a database evaluating 217 publications on water mites from 1,198 sample sites from Mexico to Patagonia. A graph of cumulative species number shows a continuous increase without reaching a plateau. Moreover, the analysis proved great differences in the knowledge of the fauna of different Latin American countries and few faunistic similarities between countries. A frequency analysis demonstrates that 45% of the known neotropical species have been found only at one locality. The analyses indicate that our knowledge of the neotropical water mite fauna is still very fragmentary. In addition, I examined the comparably well known water mite fauna of Costa Rica. Within eleven subfamilies surveyed in detail, 75% of the species were new to science. Extrapolating the Costa Rican situation to the entire Neotropic, I suggest a species number fourfold higher than currently known.