Rhinonyssus rhinolethrum (Trouessart, 1895) (Mesostigmata: Rhinonyssidae) in Netta peposaca (Vieillot, 1816) (Anseriformes: Anatidae) from Southern Brazil.

Netta peposaca is an anatid endemic to the South American continent and Rhinonyssus rhinolethrum is a rhinonissid mite of wide geographical distribution parasitizing several species of anatids. The association between these organisms has been reported in Argentina; however, the number of birds examined and the parasite indices have not been reported. Thus, the objective of this study was to know the diversity of nasal mites associated with N. peposaca in southern of Brazil and the parasitological indices. The nasal cavities of 30 birds from two locations in Rio Grande do Sul, Brazil, were examined to collect mites. Rhinonyssus rhinolethrum occurred in 16.67% of the birds with an infection intensity of 3-24 mites/host. Infections in male and female hosts showed no significant differences. This study records for the first time R. rhinolethrum and its infection indices in N. peposaca in the southern of Brazil.