A new tick species belonging to the genus Dermacentor Koch, 1844, namely, Dermacentor limbooliati n. sp., is described. Adults of this species are similar to those of Dermacentor auratus Supino, 1897 and Dermacentor compactus Neumann, 1901, with which it was previously confused. Males of D. limbooliati may be distinguished from those of D. auratus and D. compactus by the following suite of characters: relatively broad conscutum with slightly straightened lateral sides, conscutum widest approximately at mid-length, oval shape of pseudoscutum, central brown patch in the center of pseudoscutum broad and diffused and not continuous with central patch in posteromedian area, conscutum posterior to pseudoscutum rugose, wide and blunt internal spur on coxa I, relatively long, narrow, and pointed external spur on coxa I, numerous internal spurs on coxa IV and trochanter I with moderate and broadly triangular spur with tapering apex. Females of D. limbooliati may be distinguished from those of D. auratus and D. compactus by the following suite of characters: rounded shape of scutum, central brown patch broad and diffused in the center of scutum, relatively long alloscutum setae, genital aperture moderately narrow V-shaped with preatrial fold bulging, wide and blunt internal spur on coxa I, relatively long, narrow, and pointed external spur on coxae I and trochanter I with moderate and broadly triangular spur with tapering apex. D. limbooliati is known from Malaysia and Vietnam where the adults were collected from vegetation, Sus scrofa resting beds, a human, and clothing. The immature stages remain unknown.
Dermacentor tamokensis n. sp. and Dermacentor pseudocompactus n. sp. (Acari: Ixodidae) are described based on adults ex wild boar and vegetation from China, India, Malaysia, and Vietnam and males ex wild boar from Nepal, respectively. Adults of D. tamokensis n. sp. are similar to those of D. taiwanensis Sugimoto, 1935 and D. atrosignatus Neumann, 1906 but can be distinguished by the colour pattern of the conscutum and scutum, the size and density of punctations on the pseudoscutum and scutum, the width of the cornua, and the shape of female genital structures. Males of D. pseudocompactus n. sp. are most similar to those of D. compactus Neumann, 1901 but can be distinguished by the colour pattern, sculpture and punctations of the conscutum, and the shape and length of the coxal spurs.
Re-examination of the holotype of Dermacentor atrosignatus Neumann, 1906 (Acari: Ixodidae) stored in the Natural History Museum (London, UK) revealed that this taxon is identical with D. auratus Supino, 1897 and should be treated as a junior synonym of the latter species. A correct name for the distinct species previously identified as D. atrosignatus Neumann, 1906 sensu Wassef & Hoogstraal, 1984 should be D. tricuspis (Schulze, 1933) n. comb., n. stat. Adults of D. tricuspis are redescribed here. Re-examination of extensive holdings of Oriental Dermacentor Koch, 1844 ticks stored in the United States National Tick Collection revealed that a morphologically distinct new species of this genus, namely D. falsosteini D. Apanaskevich, M. Apanaskevich & Nooma n. sp. should be recognized. Adults of D. tricuspis and D. falsosteini n. sp. can be distinguished from other species of Oriental Dermacentor and each other by the colour pattern of the conscutum and scutum, the pattern of punctations on the pseudoscutum and scutum, the shape of female genital structures and spurs on coxa I. Dermacentor tricuspis is recorded from Indonesia, Malaysia, the Philippines and Thailand where the adults were mostly collected from various species of wild pigs (Artiodactyla: Suidae) and vegetation; few adults were available from other mammals (Artiodactyla: Bovidae; Carnivora: Canidae, Felidae, Ursidae; Pholidota: Manidae), as well as humans and reptiles (Squamata: Elapidae, Varanidae). One male was reared from a nymph collected on a rodent (Rodentia: Muridae). Dermacentor falsosteini n. sp. is found in Indonesia, Malaysia and Thailand where the adults were collected from bearded pig, Sus barbatus Müller, wild boar, S. scrofa Linnaeus, unidentified wild pig, Sus sp. (Artiodactyla: Suidae), Malayan tapir, Tapirus indicus Desmarest (Perissodactyla: Tapiridae), human and vegetation.