This study presents the molecular detection of Candidatus Rickettsia andeanae and Ehrlichia sp. in Amblyomma pseudoconcolor Aragão, 1908 (Acari: Ixodidae) collected on a large hairy armadillo (Chaetophractus villosus (Desmarest, 1804)). On 12 October 2020, a specimen of C. villosus was found dead on the road in Río Negro province, Argentina. Molecular detection of Rickettsia and Ehrlichia agents was performed amplifying the gltA and 16S rRNA gene, respectively. One tick, determined morphologically and genetically as A. pseudoconcolor, was collected on C. villosus. The rickettsial agent detected in A. pseudoconcolor was identified as Candidatus Rickettsia andeanae. The Ehrlichia sp. strain showed high sequence similarity to different uncultured Ehrlichia sp. detected in horses, capybaras and Ixodes ornithorhynchi from Nicaragua, Brazil and Australia, respectively. The results of this study and previous findings suggest that A. pseudoconcolor may be a potential vector of some Rickettsia and Ehrlichia bacteria of unknown pathogenicity.

T.iota e aim of this st..d/ was to izpari tick infestatiuns o ; wild birds from iour : hytogeographic :`ra.inces of Argentina. A total of 1085 birds was captured (124 species, 97 genera, r9 fannilies and 13 ordem), and ticks were collected from 265 birds (48 species, 40 genera and five ordeis). A total of 1469 ticks (1102 larvae, 363 nymphs and 4 females) belonging to 15 tick species (Atablyonuna calcaratuni, Arnblyonuna dubitatton. Arnblyonuna .-Wt o..u pi l, Atablyonuna ovale, Amblyonuna par. urn, Aniblyonuna sculptunt Arablyonuna tizrtum, Amblyonuna tiste, HaenraptrySaliS juxtaKochi, tmetnaphpalis wporbpalustis, Ixodes awitulus sensu lato, ixodcs pa. aricinus, ixodei, silvanus, lxodes sp. cf i. affinis and Omithodoros sp. cf. 0. mimon). Eighty-one new associations between bird species and stages of tick species are detected. The families Thamnophilidae, Turclidae, Thraupidae, Passerellidae, Funailidae and Troglodytidae were the most prevalent. According to the Phytogeographic Provinces invol.ed in this study, the prevalence of infection for each of them in birds was: (1) Chaco: 28.2% (11 tick species); (2) Vungas: 22.0% (8 tick species); (3) Espinal: 11.1% (2 tick species); and (4) Pampa: 3.9% (1 tick species). This study pro center dot, ided infmmation on the divemity of tick species that parasitize wild birds, the variability of the specific tick-bird associations between the different Phytogeographic Provinces and the relevance of some families of birds as hosts of different tick species.