Mites of the family Rhinonyssidae

are permanent parasites of the nasal cavities of birds. They are obligate hematophagous endoparasites. The family Rhinonyssidae currently includes about 500 described species arranged in eight genera. In the present work a complete morphobiometrical study of two populations of the genus Mesonyssus isolated from Streptopelia turtur and Streptopelia decaocto (Aves: Columbiformes) were carried out. Furthermore, the complete internal transcribed spacer 1, 5.8S gene and internal transcribed spacer 2 (ITSs) of the ribosomal DNA, and a fragment of the mitochondrial gene cytochrome oxidase I (Cox1) from five taxa belonging to Mesonyssus (Mesonyssus sp. from S. turtur, Mesonyssus sp. from S. decaocto, Mesonyssus melloi, Mesonyssus columbae and Mesonyssus minisetosum, Sternostoma turdi) were sequenced to examine the level of sequence variation and its utility in phylogeny estimation. Our data show that these molecular markers can help to discriminate between species and populations included in the “melloi complex” (M. streptopeliae and M. streptopelioides), which are morphologically very close and difficult to separate by classic methods. A comparative study with sequences from other rhinonyssid mites previously published was also carried out. The resulting phylogenetic tree inferred from the ITSs and a fragment of the mitochondrial gene cox1 sequences obtained in this work, shows differences between populations of Mesonyssus sp. from S. turtur and S. decaocto, so we can considerer they are different species. Our study suggests the usefulness of cox1 to address taxonomic and phylogenetic questions in this group of mites.