Journal Article

Molecular-phylogenetic analyses of Ixodes species from South Africa suggest an African origin of bird-associated exophilic ticks (subgenus Trichotoixodes)

Keve, Gergő, Takács, Nóra, Kontschán, Jenő, Heyne, Heloise, Plantard, Olivier, Halajian, Ali, Hornok, Sándor, Kovács, Áron Botond, Gyuranecz, Miklós, Fedorov, Denis

2023

Overview

Background Among hard ticks (Acari: Ixodidae), the genus Ixodes comprises the highest number of species, which in turn are most numerous in the Afrotropical zoogeographic region. In South Africa extensive morphological studies have been performed on Ixodes species but only few reports included molecular analyses. Methods In this study, 58 Ixodes spp. ticks, collected from ten mammalian and eight avian host species in South Africa, were molecularly and phylogenetically analyzed. In addition, a newly collected sample of the Palearctic Ixodes trianguliceps was included in the analyses. Results Among the ticks from South Africa, 11 species were identified morphologically. The majority of ticks from mammals represented the Ixodes pilosus group with two species ( n  = 20), followed by ticks resembling Ixodes rubicundus ( n  = 18) and Ixodes alluaudi ( n  = 3). In addition, single specimens of Ixodes rhabdomysae , Ixodes ugandanus , Ixodes nairobiensis and Ixodes simplex were also found. Considering bird-infesting ticks, Ixodes theilerae ( n  = 7), Ixodes uriae ( n  = 4) and ticks most similar to Ixodes daveyi (provisionally named I. cf. daveyi , n  = 2) were identified. Molecular analyses confirmed two species in the I. pilosus group and a new species ( I. cf. rubicundus ) closely related to I. rubicundus sensu stricto. Phylogenetic trees based on concatenated mitochondrial or mitochondrial and nuclear gene sequences indicated that the subgenus Afrixodes forms a monophyletic clade with bird-associated exophilic ticks (subgenus Trichotoixodes ). Ixodes trianguliceps clustered separately whereas I. alluaudi with their morphologically assigned subgenus, Exopalpiger . Conclusions Phylogenetic analyses shed new lights on the relationships of Ixodes subgenera when including multiple sequences from subgenus Afrixodes and African as well as Palearctic species of subgenera Trichotoixodes and Exopalpiger . Subgenera Afrixodes and bird-associated Trichotoixodes share common ancestry, suggesting that the latter might have also originated in Africa. Regarding the subgenus Exopalpiger , I. alluaudi is properly assigned as it clusters among different Australian Ixodes , whereas I. trianguliceps should be excluded. Graphical Abstract

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: 16S rRNA gene / ancestry / Animals / Australia / Biomedical and Life Sciences / Biomedicine / Birds / Carnivora / Cox1 gene / Cytochrome / Distribution / Entomology / Eulipotyphla / Gene sequencing / Genes / Genetic aspects / genus / Health aspects / hosts / Identification and classification / Infectious Diseases / Insects as carriers of disease / Ixodes / Ixodes - genetics / Ixodes rubicundus / Ixodes trianguliceps / Ixodes uriae / Ixodidae - genetics / Life Sciences / Mammals / Maximum likelihood method / mitochondria / monophyly / Morphology / New species / Palearctic region / Parasitology / Passeriformes / Phylogenetics / Phylogeny / Software / South Africa / species / subgenus / Taxonomy / Ticks / Tropical Medicine / Veterinary Medicine/Veterinary Science / Virology / Zoogeography / Zoological research