The genus Hyalomma: VII. Redescription of all parasitic stages of H. (Euhyalomma) dromedarii and H. (E.) schulzei (Acari: Ixodidae).

The ticks, Hyalomma (Euhyalomma) dromedarii Koch, 1844 and Hyalomma (Euhyalomma) schulzei Olenev, 1931, are considered to be the species most closely associated with camels. H. dromedarii can behave as a three-, two-, or one-host species, with the two-host life cycle seemingly most common. Camels are the main hosts of the adults, which also parasitize other domestic animals. Nymphs and larvae can use the same hosts, especially camels, as the adults, but can also parasitize rodents, leporids, hedgehogs, and birds. H. dromedarii is widely distributed in North Africa, the northern regions of West, Central, and East Africa, Arabia, Asia Minor, the Middle East, and Central and South Asia. H. schulzei is a two-host species. Camels are the principal hosts of the adults, with some records from cattle and goats, whereas the immature stages infest hares, burrowing rodents, and hedgehogs. H. schulzei has a more limited geographic distribution in Asia and Egypt than H. dromedarii, and with the exception of southeastern Iran, it is a fairly uncommon tick. Among other features that are fairly similar, males of H. dromedarii can be distinguished from those of H. schulzei by a narrow, subtriangular parma, usually very large subanal shields, and a long dorsal prolongation of the spiracular plates. Males of H. schulzei have a broad and rectangular parma, paramedian festoons that protrude posteriorly, smaller subanal shields, and a very short dorsal prolongation of the spiracular plates. The females of H. dromedarii can be distinguished from those of H. schulzei by a narrow V-shaped genital aperture compared with a very wide, deep, U-shaped genital aperture. Here all the parasitic stages of both species are illustrated and redescribed, and characteristics that distinguish the adults from those of other closely related species are supplied. Data on their hosts, geographic distribution and disease relationships are also provided.