Rhipicephalus is a genus of ticks in the family Ixodidae, the hard ticks, consisting of about 74 or 75 species. Most are native to tropical Africa. Species are difficult to distinguish from one another because most are quite similar, while individuals of one particular species can be quite variable. Most of the characteristics used to identify species pertain to male and immature specimens, and "females are sometimes simply impossible to identify". Boophilus was once considered a separate genus, but studies in the early 2000s resulted in Boophilus being made a subgenus of Rhipicephalus.