Paenungulata
Paenungulata, also known as Uranotheria, is a clade of "sub-ungulates", which groups three extant mammal orders: Proboscidea, Sirenia, and Hyracoidea. At least two more possible orders are known only as fossils, namely Embrithopoda and Desmostylia.
Molecular evidence indicates that Paenungulata is part of the cohort Afrotheria, an ancient assemblage of mainly African mammals of great diversity. The other members of this cohort are the orders Afrosoricida, Macroscelidea and Tubulidentata.
Of the three extant Paenungulate orders, hyraxes are sister to a clade containing the sirenians and elephants. The latter two, together with the extinct order Embrithopoda, are grouped as the Tethytheria, because it is believed that their common ancestors lived on the shores of the prehistoric Tethys Sea; however, recent myoglobin studies indicate that even Hyracoidea had an aquatic ancestor.
History
In 1945, George Gaylord Simpson used traditional taxonomic techniques to group these spectacularly diverse mammals in the superorder he named Paenungulata, but there were many loose threads in unravelling their genealogy. For example, hyraxes in his Paenungulata had some characteristics suggesting they might be connected to the Perissodactyla. Indeed, early taxonomists placed the Hyracoidea closest to the rhinoceroses because of their dentition.When genetic techniques were developed for inspecting amino acid differences among haemoglobin sequences the most parsimonious cladograms depicted Simpson's Paenungulata as an authentic clade and as one of the first groups to diversify among the placental mammals. The amino acid sequences reject a connection between extant paenungulates and perissodactyls.
However, a 2014 cladistic analysis placed anthracobunids and desmostylians, two major extinct groups that have been considered to be non-African afrotheres, close to each other within Perissodactyla.