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A large number of tick species are proven vectors for the transmission of bacteria, protozoa, and viruses. Soft ticks (Acari: Argasidae) in South America have been found to be the most frequent carriers of borreliae of the relapsing fever group (RFG); however, there are several information gaps specially on the taxonomy and distribution of some tick species. Here, we used light microscopy, scanning electron microscopy, and PCR amplification of a fragment of the mitochondrial 16S rRNA gene to evaluate 174 larvae of Ornithodoros(Argasidae) collected from three bat species (Eptesicus orinocensis, Molossus rufusand Noctilio albiventris) in the Orinoquia Region of Colombia. The morphological and molecular results confirmed that all the analyzed larvae corresponded to Ornithodoros hasei. Comparisons of mitochondrial 16S rDNA sequences showed low genetic divergence (0% - 0.3%) between larvae of the Department of Arauca in the Orinoquia Region and higher genetic divergence (3.4 - 4.7%) in sequences from other American countries. Our work represents the most recent collection of this species in Colombia and provides a molecular evaluation for the first time. Moreover, a new association of O. haseiwith bats such as E. orinocensisis documented. Considering the wide distribution of O. haseiin the American Continent, and its putative role as vector for Borrelia, integrative studies that involve morphological, morphometric, molecular data and experimental crosses are needed to determine if the higher genetic distances are associated with cryptic speciation, as detected in other tick complexes, or represent genetic divergences among geographically different populations of O. hasei.

The aim of this study was to assess the presence of Rickettsiain soft ticks (Acari: Argasidae) collected from insectivorous bats (Chiroptera) in Santa Fe province, Argentina. First, a subset of ticks were mounted in Hoyer’s medium to be determined by morphological characters and then confirmed by sequencing the mitochondrial 16S rRNA gene. Also ticks were processed by PCR assays using primers CS-78 and CS-323, which amplify a fragment of the Rickettsiaspp. gltAgene. Positive ticks were subjected to a second PCR round with primers Rr190.70p and Rr190.701n of the spotted fever group rickettsiae ompAgene. A phylogenetic analysis was performed with Maximum-likelihood method, and the best fitting substitution models were determined with the Akaike Information Criterion. Five bats of the species Eptesicus diminutusOsgood, 1915, Eptesicus furinalis(d’Orbigny and Gervais, 1847), Eptesicusspp. (Vespertilionidae), and Molossops temminckiiBurmeister, 1854 (Molossidae) were parasitized with Ornithodoros hasei(Schulze, 1935) larvae. One E. diminutusticks’ tested positive to “CandidatusRickettsia wissemanii”, a spotted fever group rickettsiae. The association O. hasei–“Ca.R. wissemanii” detected in this study represents the first evidence of a Rickettsiain Ornithodorosticks in Argentina and the third report of this association in America. Also, this finding constitutes the first record of “Ca. R. wissemanii” in Argentina. Finally, we found for the first time the insectivorous bats E. diminutusand E. furinalisparasitized with O. haseilarvae. These findings add two new hosts and a new location, the southernmost recorded to date, for O. hasei.

Ornithodoros atacamensisn. sp. is described from larvae collected on the lizard Liolaemus bisignatusand from free-living adults collected in desert areas from the Pan de Azúcar and Llanos de Challe National Parks, in Northern Chile. Additionally, unengorged larvae were obtained from fertilized females, which laid eggs in the laboratory. Morphological and mitochondrial 16S rDNA sequence analyses were performed in order to compare this new soft tick species with other congeneric Neotropical representatives. Larvae of O. atacamensisare morphologically closely related to Ornithodoros talajesensu stricto, Ornithodoros puertoricensis, Ornithodoros rioplatensis, Ornithodoros guaporensisand Ornithodoros hasei, all belonging to the O. talajespecies group. The larval diagnostic characters for this species are a combination of a large pyriform dorsal plate with a length of approximately 300μm, 17 pairs of dorsal setae with five central pairs, hypostome with apex pointed and dental formula 2/2 in most rows, 3/3 apically, and capsule of the Haller’s organ oval in shape without reticulations. Phylogenetic analyses inferred from the mitochondrial 16S rRNA gene and a Principal Component Analysis based on morphometric characters provide additional support to the description of O. atacamensisas an independent lineage within the genus clustering within the O. talajespecies group.