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The present study aims to perform comparative genetic characterization for R. sanguineus s.l. infesting Algerian dogs living in steppe and high plateau regions based on mitochondrial 16S rRNA gene sequencing and phylogenetic analysis. In total, 1043 ticks were collected from 147 infested dogs, including 756 ticks from 124 dogs in Djelfa and 287 ticks from 23 dogs in Bordj-Bou-Arreridj. All ticks were morphologically identified as R. sanguineus s.l., and 87 specimens were randomly selected for molecular analysis. Sequences obtained from selected ticks clustered with sequences of R. sanguineus s.l. from France, Germany, Portugal, and Spain, all of which belong to R. sanguineus s.s. The occurrence of R. sanguineus s.s. in Algeria is an interesting result given that most R. sanguineus in Africa cluster among the tropical lineage. This finding should prompt further investigation by exhaustive studies across Algerian territory. Such data can be useful to understand the dispersal route of R. sanguineus s.s. from Europe to North Africa, or whether their occurrence in Algeria is a result of historical biogeography.

Rhipicephalus turanicus ticks are widely distributed across the Palearctic and Afrotropics. These two continental populations display differences in morphological characters that raise the question of a potential species boundary. However, the taxonomic status of these morphologically divergent lineages is uncertain because R. turanicus from Cyprus and Zambia have been shown to interbreed and produce fertile hybrids. We employ integrative taxonomy that considers data from mtDNA sequences (12S and 16S rDNA), geographic distribution, traditional (qualitative) morphology, as well as shape outlines of female spiracles and male adanal plates measured in a geometric morphometric framework (quantitative morphology) to resolve this taxonomic issue. Molecular lines of evidence (12S and 16S rDNA) support taxonomic separation between ticks sampled in the Afrotropics and the Palearctic. This is corroborated by qualitative and quantitative morphology. Within the Palearctic, two sub-lineages were recovered based on sequence data that loosely correspond to southern Europe and the Middle East/Asia. One new species, Rhipicephalus afranicus n. sp. is described from South Africa with a geographic distribution that extends into eastern Africa. This leaves R. turanicus sensu lato comprised of two lineages located in southern Europe and the Middle East/Asia. The type locality for R. turanicus is in Uzbekistan, thus the Middle East/Asia lineage is considered R. turanicus sensu stricto. Detailed descriptions are provided for R. afranicus n. sp. and R. turanicus sensu stricto together with high resolution images. Speciation is attributed to recent Sahara desert expansion that formed a natural barrier to dispersal approximately 5-7 million years ago. However, reproductive potential between these two species suggests that divergence time and mode of speciation were not sufficient for the development of reproductive isolation. We suggest speciation was complicated by divergence and population reintegration events driven by oscillating climatic conditions contributing to reticulate evolution and maintenance of compatibility between reproductive mechanisms. This study represents an integrative (iterative) approach to delimiting Rhipicephalus spp., and provides the first application of shape outlines for female spiracles and male adanal plates measured in a geometric morphometric framework, applied to testing species boundaries between ticks., (Copyright © 2020 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.)