MITOCHONDRIAL 16S RDNA SEQUENCES AND PHYLOGENETIC-RELATIONSHIPS OF SPECIES OF RHIPICEPHALUS AND OTHER TICK GENERA AMONG METASTRIATA (ACARI,IXODIDAE)

The mitochondrial 16S rRNA gene sequences of the following eight Europ ean Melastriata tick species were obtained by direct polymerase-chain- reaction cycle sequencing and silver-staining methods: Rhipicephalus b ursa, R. pusillus, R. sanguineus, R. turanicus, Boophilus annulatus, D ermacentor marginatus, Haemaphysalis punctata, and Hyalomma lusitanicu m. This mitochondrial gene seems to be a good marker for the establish ment of generic relationships among closely related tick species, but it does not seem to be useful for comparisons of distantly related tax a. The molecular data provide very strong support for the monophyly of the Rhipicephalinae, including Hyalomma spp. However, the genus Rhipi cephalus may not be considered a monophyletic group; in all analyses c arried out in this study, R. bursa clustered with Boophilus spp. The h igh percentage of similarity (98.7%) observed between R. sanguineus an d R. turanicus sequences would suggest that these species recently div erged within the Rhipicephalus genus. Phylogenetic analyses showed a m onophyletic relationship among Amblyomminae taxa. The relationships be tween Haemaphysalis species and the true placement of this genus withi n Metastriata could not be resolved.