Laurasiatheria Laurasiatheria Laurasiatheria is a clade of placental mammals that originated on the northern supercontinent of Laurasia 99 million years ago. The clade includes shrews, pangolins, bats, whales, carnivorans, odd-toed and even-toed ungulates, among others. 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.
Supercontinent Neoarchean age broke off at ~2480 and and portions of them later collided to form Nuna (Northern Europe North America) (). Nuna continued to develop during the Mesoproterozoic, primarily by lateral accretion of juvenile arcs, and in Nuna collided with other land masses, forming Rodinia. Between ~825 and Rodinia broke apart. However, before completely breaking up, some fragments of Rodinia had already come together to form Gondwana (also known as Gondwanaland) by . Pangaea formed by through the collision of Gondwana, Laurasia (Laurentia and Baltica), and Siberia. The second model (Kenorland-Arctica) is based on both palaeomagnetic and geological evidence and