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 name comes from the theory that these mammals evolved on the supercontinent of Laurasia, after it split from Gondwana when Pangaea broke up.
It is a sister group to Euarchontoglires (or Supraprimates) with which it forms the clade Boreoeutheria.
Laurasiatheria includes the following extant taxa:
Eulipotyphla, having subsumed:
Erinaceomorpha: hedgehogs and gymnures (see Erinaceidae)
the remaining families of Soricomorpha: moles, shrews, solenodons (cosmopolitan distribution)
Chiroptera: bats (cosmopolitan)
Perissodactyla: odd-toed ungulates including horses, tapirs and rhinoceroses
Artiodactyla: even-toed ungulates including camels, pigs, ruminants (giraffes, deer, antelopes, cattle, sheep, goats, etc.),
hippopotamuses and cetaceans
Cetacea: whales, dolphins, and porpoises
Ferae (unranked) containing the orders:
Pholidota: pangolins ('scaly anteaters') (Africa, South Asia)
Carnivora: cats, dogs, bears, seals, and others (cosmopolitan)
Uncertainty still exists regarding the phylogenetic tree for extant laurasiatherians, primarily due to disagreement about the placement of Chiroptera and Perissodactyla.
Based on morphological grounds, Chiroptera had long been classified in the superorder Archonta (e.g. along with treeshrews and the gliding colugos) until genetic research instead showed their kinship with the other laurasiatherians.
The studies conflicted in terms of the exact placement of Chiroptera, however, with it being linked most closely to groups such as Eulipotyphla, Ferae or with Perissodactyla and Ferae in the Pegasoferae proposal.
A 2011 study found that "trees reconstructed [...] for the 1,608-gene data set fully support [...] a basal position for Eulipotyphla and a more apical position for Chiroptera" (see cladogram below) and concluded that "Pegasoferae [...] does not appear to be a natural group."
A 2012 study supports the previous conclusions using a large genomic dataset, and places Eulipotyphla as a basal order and Chiroptera as sister to Cetartiodactyla, with maximal support for all nodes of their phylogenetic tree.
The exact position of Perissodactyla remains less certain, with some studies linking it with Ferae into a proposed clade Zooamata while others unite it with Cetartiodactyla into Euungulata, a clade of 'true ungulates', yet some authors found better (but not full) support for the latter, while others found Perissodactyla to be sister to Carnivora.

Two 2013 studies retrieve that chiropterans, carnivores, and euungulates form a clade, therefore involving that Eulipotyphla might be the sister 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.

Meridiungulata (Collagen sequences found in Macrauchenia and Toxodon indicate what are now understood to be the sister taxon to perissodactyls)
Condylarthra (paraphyletic in relation to true ungulates, possibly polyphyletic since some forms may be afrotheres or even non-placental eutherians)
Dinocerata (natural clade closely related to perissodactyls and meridiungulates)
Mesonychia (natural clade, though several members, such as Andrewsarchus, are now thought to belong in other groups)
Creodonta (potentially polyphyletic)
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 name comes from the theory that these mammals evolved on the supercontinent of Laurasia, after it split from Gondwana when Pangaea broke up. It is a sister group to Euarchontoglires (or Supraprimates) with which it forms the clade Boreoeutheria. Laurasiatheria includes the following extant taxa:
Eulipotyphla, having subsumed:
Erinaceomorpha: hedgehogs and gymnures (see Erinaceidae)
the remaining families of Soricomorpha: moles, shrews, solenodons (cosmopolitan distribution)
Chiroptera: bats (cosmopolitan)
Perissodactyla: odd-toed ungulates including horses, tapirs and rhinoceroses
Artiodactyla: even-toed ungulates including camels, pigs, ruminants (giraffes, deer, antelopes, cattle, sheep, goats, etc.), hippopotamuses and cetaceans
Cetacea: whales, dolphins, and porpoises
Ferae (unranked) containing the orders:
Pholidota: pangolins ('scaly anteaters') (Africa, South Asia)
Carnivora: cats, dogs, bears, seals, and others (cosmopolitan)
Uncertainty still exists regarding the phylogenetic tree for extant laurasiatherians, primarily due to disagreement about the placement of Chiroptera and Perissodactyla. Based on morphological grounds, Chiroptera had long been classified in the superorder Archonta (e.g. along with treeshrews and the gliding colugos) until genetic research instead showed their kinship with the other laurasiatherians. The studies conflicted in terms of the exact placement of Chiroptera, however, with it being linked most closely to groups such as Eulipotyphla, Ferae or with Perissodactyla and Ferae in the Pegasoferae proposal. A 2011 study found that "trees reconstructed [...] for the 1,608-gene data set fully support [...] a basal position for Eulipotyphla and a more apical position for Chiroptera" (see cladogram below) and concluded that "Pegasoferae [...] does not appear to be a natural group." A 2012 study supports the previous conclusions using a large genomic dataset, and places Eulipotyphla as a basal order and Chiroptera as sister to Cetartiodactyla, with maximal support for all nodes of their phylogenetic tree. The exact position of Perissodactyla remains less certain, with some studies linking it with Ferae into a proposed clade Zooamata while others unite it with Cetartiodactyla into Euungulata, a clade of 'true ungulates', yet some authors found better (but not full) support for the latter, while others found Perissodactyla to be sister to Carnivora.
Two 2013 studies retrieve that chiropterans, carnivores, and euungulates form a clade, therefore involving that Eulipotyphla might be the sister 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.
Meridiungulata (Collagen sequences found in Macrauchenia and Toxodon indicate what are now understood to be the sister taxon to perissodactyls)
Condylarthra (paraphyletic in relation to true ungulates, possibly polyphyletic since some forms may be afrotheres or even non-placental eutherians)
Dinocerata (natural clade closely related to perissodactyls and meridiungulates)
Mesonychia (natural clade, though several members, such as Andrewsarchus, are now thought to belong in other groups)
Creodonta (potentially polyphyletic)
Laurasiatheria