New records and phylogenetic position of Ornithodoros knoxjonesi (Ixodida: Argasidae)

Abstract

Larvae of Ornithodoros knoxjonesi collected at five localities in three countries were studied using morphologicaland molecular methods to confirm this species? taxonomic validity. The larva of O. knoxjonesi is characterized ashaving 14 pairs of dorsal setae, eight pairs of ventral setae, plus a posteromedian seta; an elongate dorsal plate,tapered anteriorly; and a hypostome that is narrower near its midlength, with posteriorly projecting denticles.Although the larvae of O. knoxjonesi and Ornithodoros peropteryx are morphologically quite similar, the larva ofO. knoxjonesi is characterized as having dorsal setae that are wider at the tip than at the base, while in O.peropteryx these setae are narrower at the tip than at the base; moreover, the dorsal setae are shorter in O.knoxjonesi (Al 0.037?0.065; Pl 0.035?0.059) than in O. peropteryx (Al 0.120−0.132; Pl 0.080−0.096). Thesespecies also differ in that O. knoxjonesi possesses only the Al seta on tarsus I, whereas O. peropteryx has both Aland Pl setae. And while both species have two setae on coxae I-III, in O. knoxjonesi the anterior seta is taperingand smooth and the posterior is fringed, while both setae are fringed in O. peropteryx. At the molecular level,based on a maximum likelihood analysis using approximately 400 bp of the mitochondrial 16S rDNA gene, O.knoxjonesi appears as an independent lineage, separated from O. peropteryx by a genetic distance of 16.28 %.Balantiopteryx plicata is a common host of O. knoxjonesi; however, in this work we report Pteronotus personatusand Pteronotus gymnonotus as new hosts of this tick species.