Occurrence of morphologic variability in tick Hyalomma anatolicum anatolicum (Acari: Ixodidae)

BACKGROUND: Taxonomy and identification of the ticks in the genus Hyalomma, the most significant vectors of animal and human pathogen agents, have always been debatable. Scientists believe that variation within the taxa of the genus Hyalomma is the most important factor which causes misidentification. OBJECTIVES: The purpose of this study is to identify valuable characters for male H. anatolicum anatolicum by statistical methods. METHODS: Tick specimens from 11 geographical regions in Iran including Khuzestan, Lorestan, Sistan & Baluchistan, Yazd, South and Razavi Khorasan provinces as well as an island in southern Iran were studied. Totally, 3 qualitative and 9 quantitative characters were measured by a stereomicroscope armed with scaled lens and the data were analyzed by SPSS software. Also, coefficient of difference (C.D.) was calculated for some important characters. Then, varied shapes of species were drawn with a drawing tube connected to a light stereomicroscope. RESULTS: One way ANOVA test revealed significant differences among the quantitative characters in 11 zones (p<0.001), also each zone to another zone by LSD. No significant differences (p>0.14) in the lateral grooves length/scutum length ratio character were found. The C.D. value equal to 1.28, is a conventional level of subspecific differences but is lesser in this study than this category. CONCLUSIONS: The present study focused on the determination a quantitatively relative stable trait for differentiating H. a. anatolicum. Therefore, lateral groove is introduced as a reliable character for interspecific identification of species. Our study supports this matter since the value of this character, relative to scutum length in the under studied regions was not statistically significant. This means that the variation range of the mentioned character in the specimens is much limited.