WAfrotheria is a clade of mammals, the living members of which belong to groups that are either currently living in Africa or of African origin: golden moles, elephant shrews, tenrecs, aardvarks, hyraxes, elephants, sea cows, and several extinct clades. Most groups of afrotheres share little or no superficial resemblance, and their similarities have only become known in recent times because of genetics and molecular studies. Many afrothere groups are found mostly or exclusively in Africa, reflecting the fact that Africa was an island continent from the early Cenozoic until around 25 million years ago, when the Tethys Sea shrank.
WAmeridelphia is traditionally a superorder that includes all marsupials living in the Americas except for the Monito del monte (Dromiciops). It is now regarded as a paraphyletic group.
WThe Archonta are a now-abandoned group of mammals, considered a superorder in some classifications, which consists of these orders:Primates Plesiadapiformes Scandentia (treeshrews) Dermoptera (colugos)
WAustralidelphia is the superorder that contains roughly three-quarters of all marsupials, including all those native to Australasia and a single species from South America. All other American marsupials are members of the Ameridelphia. Analysis of retrotransposon insertion sites in the nuclear DNA of a variety of marsupials has shown that the South American monito del monte's lineage is the most basal of the superorder.
WEuarchontoglires is a clade and a superorder of mammals, the living members of which belong to one of the five following groups: rodents, lagomorphs, treeshrews, colugos and primates.
WLaurasiatheria is a clade of placental mammals that includes hedgehogs, even-toed ungulates, whales, bats, odd-toed ungulates, pangolins, and carnivorans, among others. The clade originated on the northern supercontinent of Laurasia. Its last common ancestor is supposed to have diversified ca. 76 to 91 million years ago.
WPreptotheria is a superorder of placental mammals proposed by McKenna & Bell in their classification of mammals.
WXenarthra is a major clade of placental mammals unique to the Americas. There are 31 living species: the anteaters, tree sloths, and armadillos. Extinct xenarthrans are the glyptodonts, the ground sloths, and the aquatic sloths. Xenarthrans originated in South America during the Paleocene about 59 million years ago. They evolved and diversified extensively in South America during the continent's long period of isolation in the early to mid Cenozoic Era. They spread to the Antilles by the early Miocene and, starting about 3 Mya, spread to Central and North America as part of the Great American Interchange. Nearly all of the formerly abundant megafaunal xenarthrans became extinct at the end of the Pleistocene.