Abstract

In South America, early descriptions of soft tick species were based on examination of the external morphology of the larval stages. In many cases, specimens were collected only once as it is the case of some bat-associated Ornithodoros spp. If we are to understand the systematic scenario of South American soft ticks, these species become axial questions to be re-studied from a morphological and molecular point of view. The objective of this study was to assess the taxonomic identity of soft tick larvae collected on bats inhabiting crevices of a large rock in the Rondonia State (RO), Brazilian Amazon. After a detailed morphological analysis using light microscopy, three large engorged larvae sharing the same phenotype were identified as Ornithodoros setosus Kohls, Clifford Jones, 1969, a species collected in 1964 on bats in RO. Remarkably, maximum parsimony and Bayesian phylogenetic analyses based on tick 16S rRNA mitochondrial gene sequences obtained from two of these specimens showed that O. setosus indeed corresponds to a species of Nothoaspis Keirans Clifford, 1975. Therefore, a new combination, Nothoaspis setosus (Kohls, Clifford Jones, 1969), is herein proposed. While an elongated triangular dorsal plate with a curvy-notched posterior margin, and bulges in the lateral margins of basis capitulum correspond to common characters in larvae of the genus Nothoaspis, polymorphic traits are represented by minute cornua in the basis of the capitulum, the dentition of the hypostomal tip, triangular spurs on coxae I, and the number of dorsal and circumanal setae.