ABSTRACTOrnithodoros faccinii Barros-Battesti, Landulfo & Luz 2015, a recently described species of soft tick, was collected from Thoropa miliaris (Spix, 1824), an amphibian of the family Cycloramphidae, in the municipality of Itaguai, in the state of Rio de Janeiro. Primary aspects of the ecology of O. faccinii and its relationship with T. miliaris are still largely unknown. The aims of this study were to verify the distribution range, the presence of other stage and site preference for parasitism of O. faccinii on the anuran’s body. To this end, 1026 specimens of T. miliaris from five important herpetological collections in Brazil were examined, 97 of which were parasitized by 433 larvae of O. faccinii. The geographical distribution of O. faccinii appears to be associated with that of T. miliaris, and several hypotheses are proposed regarding the behaviour of the larvae and the absence of parasitizing nymphs and adults. Thirteen municipalities in the state of Rio de Janeiro and other municipalities in t...