The genetic identity of Ixodes granulatus ticks was determined for the first 
time in Taiwan. The phylogenetic relationships were analyzed by comparing the 
sequences of mitochondrial 16S ribosomal DNA gene obtained from 19 strains of 
ticks representing seven species of Ixodes and two outgroup species 
(Rhipicephalus sanguineus and Haemaphysalis inermis). Four major clades could be 
easily distinguished by neighbour-joining analysis and were congruent by 
maximum-parsimony method. All these I. granulatus ticks of Taiwan were 
genetically affiliated to a monophyletic group with highly homogeneous sequences 
(92.2-99.3% similarity), and can be discriminated from other Ixodes species and 
other genera of ticks with a sequence divergence ranging from 11.7 to 30.8%. 
Moreover, intraspecific analysis revealed that two distinct lineages are evident 
between the same species of I. granulatus ticks collected from Taiwan and 
Malaysia. Our results demonstrate that all these I. granulatus ticks of Taiwan 
represent a unique lineage distinct from the common vector ticks (I. ricinus 
complex) for Borrelia burgdorferi spirochetes.