Laurasiatheria

Laurasiatheria ("laurasian beasts") is a superorder of placental mammals that groups together order Eulipotyphla and clade Scrotifera. It is a sister group to Euarchontoglires with which it forms the magnorder Boreoeutheria. Laurasiatheria was discovered on the basis of the similar gene sequences shared by the mammals belonging to it; no anatomical features have yet been found that unite the group. The Laurasiatheria clade is based on DNA sequence analyses and retrotransposon presence/absence data. The superorder originated on the northern supercontinent of Laurasia, after it split from Gondwana when Pangaea broke up. Its last common ancestor is supposed to have diversified ca. 76 to 90 million years ago.

Etymology
The name of this superorder comes from the theory that these mammals evolved on the supercontinent of Laurasia.

Classification and phylogeny
Uncertainty still exists regarding the phylogenetic tree for extant laurasiatherians, primarily due to disagreement about the placement of orders Chiroptera and Perissodactyla. Based on morphological grounds, bats (order Chiroptera) had long been classified in the superorder Archonta (e.g. along with primates, treeshrews and the gliding colugos) until genetic research instead showed their kinship with the other laurasiatheres. The studies conflicted in terms of the exact placement of Chiroptera, however, with it being linked most closely to groups such as order Eulipotyphla in the clade Insectiphillia. Two 2013 studies retrieve that bats, carnivorans and euungulates form a clade Scrotifera, therefore involving that Eulipotyphla might be a basal group to all other Laurasiatheria taxa.

Laurasiatheria is also posited to include several extinct orders and superorders. At least some of these are considered wastebasket taxa, historically lumping together several lineages based on superficial attributes and assumed relations to modern mammals. In some cases, these orders have turned out to either be paraphyletic assemblages, or to be composed of mammals now understood not to be laurasiatheres at all.
 * Condylarthra (paraphyletic in relation to true ungulates, possibly polyphyletic since some forms may be afrotheres or even non-placental eutherians)
 * Creodonta (order closely related to Carnivora, now polyphyletic and split in two orders: Hyaenodonta and Oxyaenodonta)
 * Dinocerata (natural order closely related to perissodactyls)
 * Meridiungulata (Collagen sequences found in Macrauchenia and Toxodon indicate what are now understood to be the sister taxon to perissodactyls, though in 2021 this clade is found to be polyphyletic, with some members being classified as afrotheres)
 * Mesonychia (natural clade, though several members, such as genus Andrewsarchus, are now thought to belong in other groups)