Laurasiatheria

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Laurasiatheria is a clade with the rank of cohort or super-order, of the Placentalia (living) or Eutheria (Placentals and their extinct ancestors) subclass of mammals, 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 (Supraprimates). It includes the following extant orders:

Core Insectivora: moles, hedgehogs, shrews, solenodons (cosmopolitan)
Chiroptera: bats (cosmopolitan)
Cetartiodactyla: cosmopolitan; includes former orders Cetacea (whales, dolphins and porpoises) and Artiodactyla (even-toed ungulates, including pigs, hippopotamus, camels, giraffe, deer, antelope, cattle, sheep, goats).
Perissodactyla: odd-toed ungulates
Ferae:
*Pholidota: pangolins or scaly anteaters (Africa, South Asia).
*Carnivora: carnivores (cosmopolitan)

Within the Laurasiatheria, the Insectivora appears to be the most divergent branch. Some studies link the Perissodactyla and Ferae in a clade Zooamata; others link Perissodactyla and Cetartiodactyla in a clade of true ungulates. Neither clade is well supported.

Laurasiatheria is also posited to include several extinct orders:

References

William J. Murphy, Eduardo Eizirik, Mark S. Springer et al., Resolution of the Early Placental Mammal Radiation Using Bayesian Phylogenetics,Science, Vol 294, Issue 5550, 2348-2351 , 14 December 2001.
Jan Ole Kriegs, Gennady Churakov, Martin Kiefmann, Ursula Jordan, Juergen Brosius, Juergen Schmitz. (2006) Retroposed Elements as Archives for the Evolutionary History of Placental Mammals. PLoS Biol 4(4): e91.[link]

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