 When alive, they would have borne a strong but superficial resemblance to modern rhinoceroses; however, they were not closely related to them (or any other perissodactyl), instead being more closely related to hyraxes, elephants, sirenians, and possibly desmostylians (as part of the superorder afrotheria).The last genus, "Arsinoitherium", was first recovered from the Latest Eocene of the Fayum; it disappears from the fossil record altogether before the end of the Early Oligocene.The name honors the wife of Ptolemy II, Queen Arsinoe II of Egypt, as the first fossils of "Arsinoitherium" were found near the ruins of her palace.