Scanning electron microscopy and morphometrics of nymph and larva of the tick Hyalomma rufipes Koch, 1844 (Acari: Ixodidae).

The genus Hyalomma comprises the most ixodid tick species that parasitize camels in Egypt. Although the immature stages of tick species play an important role in distribution of ticks and tick-borne diseases, the identification depends mainly on the adult stage. Therefore, this study tries to identify the specific characteristics of both nymph and larva of Hyalomma rufipes Koch, 1844 using scanning electron microscopy and morphometric analysis in order to differentiate them easily from those of other Hyalomma spp. described before in Egypt. Results showed that the nymph and larva of H. rufipes can be easily identified from those of H. excavatum Koch, 1844, H. dromedarii Koch, 1844 and H. impressum Koch, 1844 but they are strongly close to H. marginatum Koch, 1844. The nymph of H. rufipes can be distinguished from H. marginatum by the number and distribution of dorsal and ventral idiosomal setae and the distribution of sternal setae. All morphological characteristics of H. rufipes larva resemble those of H. marginatum larva. The measurements of nymph and larva structures of H. rufipes are significantly lower than those of H. marginatum.