Cosmiomma hippopotamensis (Denny, 1843) is one of the most
unusual, beautiful and rare tick species known to the world. All stages of this species
possess a unique morphology, on the one hand making them easy to identify, while
on the other they exhibit similarities to certain species of Amblyomma, Dermacentor
and Hyalomma. Adults of C. hippopotamensis have been collected on only two
occasions from their hosts, namely Hippopotamus amphibius and Diceros bicornis
and have been recorded from only a few widely separated localities in East and
southern Africa. Here the larva and nymph are described and illustrated for the first
time, while the male and female are illustrated and redescribed. Data on the
phylogenetic position, hosts, geographic distribution and life cycle of C.
hippopotamensis are also provided.