Ornithodoros Koch, 1844

Sun, Yi, Xu, Rongman, Liu, Zengjia, Wu, Mingyu & Qin, Tong, 2019, Ornithodoros (Ornithodoros) huajianensis sp. nov. (Acari, argasidae), a new tick species from the Mongolian marmot (Marmota bobak sibirica), Gansu province in China, International Journal for Parasitology: Parasites and Wildlife 9, pp. 209-217 : 213-214

Genus: Ornithodoros Koch, 1844

Species: Ornithodoros (Ornithodoros) huajianensis Sun, Xu, Liu and Wu.

Type-host: Marmota bobak sibirica ( Mammalia: Rodentia : Sciuromorpha).

Type-locality: Huajian village (N37̊36′ 57.93 E 103̊04′24.91, elevation 1756 m), Gulang county, Gansu province, China .

Collectors and date of collection: Z. J. Liu, Jun 5, 1991. Type materials: Holotype female, was collected from female marmots collected in Huajian village , Gulang county , Gansu province, China, in 1991. It was preserved in alcoholic liquids deposited in the Medical Entomology Gallery of Academy of Military Medical Sciences, Beijing, China ( AMMSC). (AMMSC-T-10823); Paratype, 3 nymphs, 2 females and 3 males, same data as holotype. Deposited in the Medical Entomology Gallery of Academy of Military Medical Sciences, Beijing, China ( AMMSC). (AMMSC-T- 10823∼ AMMSC-T-10830) .

Gene sequences: The mitochondrial 16S rDNA partial sequence of

5.1. Remarks

The newly described species O. (O.) huajianensis was assigned into genus Ornithodoros for its distinctive morphologic features, including suboval flat body with blunt rounded anterior end, well developed denticulated hypostome and round margin not clearly defined (Nuttall et al., 1908; Clifford et al., 1964). Genus Ornithodoros is readily separated from genera Chiropterargas and Carios by the presence of paired organs or poorly developed transverse postanal groove, and from genus Otobius by the striated and spinose integument, panduriform body narrowed in middle ( Clifford et al., 1964; Klompen and Oliver, 1993). Within the genus Ornithodoros , no Microargas, Ornamentum and Ornithodoros but for 2 Pavlovskyella species was recorded in China. The newly described species can be distinguished, in subgenus level, by the absence of cheeks around basis capitulum, transverse postanal groove and medium postanal one. The subgenus Ornamentum can also be differential diagnosed by distinctive ornated tops on the flatten mammillae ( Clifford et al., 1964), whereas the unique features of the long, apical fringed setae around the transverse oval body outline ( Hoogstraal and Kohls, 1966, 1973) can make the Microargas members be easily figured out. Considered that the presence of distinct dorsoventral groove, preanal groove and the well-marked lobes on tarsi and metatarsi, together with the absence of eyes and lack of both transverse postanal groove and median postanal groove ( Bakkes et al., 2018), we classified the newly described species O. (O.) huajianensis into O. moubata group of the subgenus Ornithodoros . The comparison of geometric morphologic shapes of tarsi I further indicates that the new species resembles with O. (O.) indica , O. (O.) procaviae , O. (O.) eremicus , O. (O.) moubata and O. (O.) compactus in O. moubata group. However, O. (O.) indica differ markedly with O. (O.) huajianensis by the dental formula 4|4 and 2 times longer palp II as palp I (Rau and Rao, 1971), although O. (O.) indica was the only species described from the foothills of Himalayas about 1500 Km away from Gulang county, China where the new species was found. Whereas, the presence of hood, triangular cheeks, 2 pairs of posthypostomal setae and much shorter palp II in O. (O.) procaviae from Israel in Palearctic realm (Theodor and Costa, 1960) separated it from O. (O.) huajianensis . And also, O. (O.) eremicus from North America in Nearctic realm, bears 2|2 dental formula on the hypostome, much shorter posthypostomal setae and the absence of lobe on tarsi V ( Cooley and Kohls, 1941), which make O. (O.) eremicus distinguishable from O. (O.) huajianensis . Furthermore, the adults and nymph of O. compactus with flat and tile like mammillae integument, shows distinctive morphological differences from O. (O.)

huajianensis n. sp. and O. (O.) moubata , whose mammillae are bulbous,

sub-equally sized and tightly spaced ( Bakkes et al., 2018). O. (O.)

huajianensis n. sp. closely resembles O. (O.) moubata , from which,

however, it may easily be distinguished by the details of male genital apron ( Fig. 3 , F), the presence of a shallow camerostome and smaller mammillae with single seta mixed with larger ones (Supplemental Figs. S2 and A; Supplemental Figs. S4 and A). Whereas the broad crescent tongue and short, broad sub-rectangular posterior labium with slight concaved anterior margin presents in the male genital apron, no camerostome or smaller mammillae visible in both sexes of O. (O.) moubata ( Fig. 3 G , Supplemental Figs. S6 and B).

Data from 16S rRNA genes also agree to distinguish O. (O.) huajianensis n. sp. and test the monophyly of the subgenus Ornithodoros in the phylogenetic analysis as shown in Fig. 5 . There are two clades formed due to the genetics difference between the O. (O.) moubata group and O. (O.) savignyi group, which is supported by the absence or presence of eyes in phenotypic morphology. The new species is closely related to O. (O.) moubata (Bayesian posterior probabilities 0.905), occurring in South Africa, Zimbabwe (unconfirmed records in Mozambique, Tanzania, Kenya and Botswana) (Nuttall et al., 1908; Bakkes et al., 2018) and O. (O.) compactus (Bayesian posterior probabilities 0.895) restricted to South Africa (Walton, 1962). The former species was recorded parasites on warthog, porcupine, pangolin, pig, goat, dog and occasionally human, while the later species were only found on tortoise including Chersina spp., Geochelone spp. Homopus spp. Psammobates spp. and Testudo spp. Therefore, a new species is nominated as O. (O.) huajianensis strongly supported by morphologic and phylogenetic evidences.

Figures

Fig. 3. Ornithodoros huajianensis n. sp. (male, paratype): A) basis capitulum; B) ventral view, entire; C) Coxa I ∼ IV; D) tarsi II and IV; E) Spiracle plate; F) genital apron； G） comparative morphology of genital apron in O. moubata.

Fig. 2. Ornithodoros huajianensis n. sp. (female, holotype): E) Tarsi I ∼ IV; F) Spiracle plate; G) genital apron.

Fig. 4. Ornithodoros huajianensis n. sp. (nymph, paratype): A) ventral view, entire; B) Coxa I ∼ IV; C) basis capitulum; D) tarsi II and IV; E) Spiracular plate.

Fig. 5. Phylogenetic tree including Ornithodoros huajianensis n. sp. and other selected species of Ixodes based on 16S rDNA. The alignment was produced using Clustal X and the tree was inferred by means of the MP method with 500 replicates of random addition. The species Otobius megnini was used as outgroup. The Bayesian support (posterior probability) values are derived from 1,000,000 replicates.