A new subgenus, Australixodes n. subgen. (Acari: Ixodidae), for the kiwi tick, Ixodes anatis Chilton, 1904, and validation of the subgenus Coxixodes Schulze, 1941 with a phylogeny of 16 of the 22 subgenera of Ixodes Latreille, 1795 from entire mitochondrial genome sequences

Margaropus Karsch, 1879 is not closely related to Boophilus Curtice, 1891 (Acari: Ixodidae)

Margaropus Karsch, 1879 and Boophilus Curtice, 1891 have been thought to be sister-taxa for over 75 years since these ticks share features like circular spiracles, no festoons, no distinct grooves behind the anus and one-host life cycles. We inferred the first phylogeny with Margaropus from 4,218 bp of mitochondrial (cox 1, 12S) and nuclear DNA (ITS2, 18S rRNA). Margaropus is not the sister-group to Boophilus or even closely related to Boophilus, but rather Margaropus is either the sister-group to, or embedded in, the genus Rhipicephalus.

American mitogenome reference for the tropical brown dog tick, Rhipicephalus linnaei (Audouin, 1826)

The brown dog tick, Rhipicephalus linnaei (Audouin, 1826), is distributed across the American continent and is formerly known as the "tropical lineage". It belongs to the Rhipicephalus sanguineus (Latreille, 1806) species complex, referred to as R. sanguineus (sensu lato). Mitochondrial genome sequences are frequently used for the identification and represent reference material for field studies. In the present study, the entire mitochondrial genomes of R. linnaei (∼15 kb) collected from dogs in Mexico were sequenced and compared with available mitogenomes of R. sanguineus (s.l.). The mitochondrial genome is ∼90% identical to the reference genome of R. sanguineus (sensu stricto, former "temperate lineage") and > 99% identical to R. linnaei mitogenome derived from the neotype. Two additional mitogenomes were obtained and described as R. linnaei and R. turanicus from dogs in Saudi Arabia. The present study delivers a molecular reference for R. linnaei from America and complements R. linnaei mitogenomes from Africa, Asia and Australia. We propose to consider the complete mitogenome, as the reference for American R. linnaei, even when partial mitochondrial cox1, 12S rRNA or 16S rRNA genes are characterised.

A new subgenus of hard ticks, Filippoviella n. subgen. (Acari: Ixodidae) comprising Ixodes trianguliceps Birula, 1895 and I. ghilarovi Filippova & Panova, 1988, parasites of small mammals in Europe and Asia

We establish a new subgenus, Filippoviella n. subgen. (Acari: Ixodidae) based on two species formerly assigned to the subgenus Exopalpiger Schulze, 1935 in the genus Ixodes Latreille, 1795. Ixodes (Filippoviella) trianguliceps Birula, 1895 is a tick species broadly distributed throughout Europe and western Siberia, the females, nymphs and larvae of which mostly feed on small mammals such as shrews and rodents. Ixodes (Filippoviella) ghilarovi Filippova & Panova, 1988 is found in the Caucasus region on rodents and shrews. The type species of this new subgenus is Ixodes trianguliceps. The major morphological differences allowing discrimination of the two species of Filippoviella n. subgen from members of the subgenus Exopalpiger are the shape of the idiosoma, shape of the basis capituli, development of palpal segment I, the suture between palpal segments II and III, development of syncoxae and chaetotaxy. We sequenced the entire mitochondrial genome of I. trianguliceps; according to our phylogeny from 10 protein-coding mitochondrial genes of 17 of the 23 Ixodes subgenera (34 spp.), I. (Filippoviella) trianguliceps is basal to the "other Ixodes" and polyphyletic with I. (Exopalpiger) fecialis Warburton & Nuttall, 1909.

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

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.