Laurasiatheria (/lɔːrˌeɪʒəˈθɪəriə, -θɛriə/; "Laurasian beasts") is a superorder of placental mammals that groups together true insectivores (eulipotyphlans), bats (chiropterans), carnivorans, pangolins (pholidotes), even-toed ungulates (artiodactyls), odd-toed ungulates (perissodactyls), and all their extinct relatives (pan-euungulates). From systematics and phylogenetic perspectives, it is subdivided into 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, although a few have been suggested such as a small coracoid process, a simplified hindgut (reversed in artiodactyls), high intelligence, lack of grasping hands (though mimicry of grasping is observed in felines) and allantoic vessels that are large to moderate in size. 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 lived between ca. 76 to 90 million years ago.
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Laurasiatheria in the context of Ungulates
Ungulates are members of the diverse clade Euungulata, which primarily consists of large mammals with hooves. Once part of the taxon "Ungulata" along with paenungulates and tubulidentates, as well as several extinct taxa, "Ungulata" has since been determined to be a polyphyletic grouping based on molecular data. As a result, true ungulates had since been reclassified to the newer clade Euungulata in 2001 within the clade Laurasiatheria, while Paenungulata and Tubulidentata had been reclassified to the distant clade Afrotheria. Alternatively, some authors use the name Ungulata to designate the same clade as Euungulata.
Living ungulates are divided into two orders: Perissodactyla including equines, rhinoceroses, and tapirs; and Artiodactyla including cattle, antelope, pigs, giraffes, camels, sheep, deer, and hippopotamuses, among others. Cetaceans such as whales, dolphins, and porpoises are also classified as artiodactyls, although they do not have hooves. Most terrestrial ungulates use the hoofed tips of their toes to support their body weight while standing or moving. Two other orders of ungulates, Notoungulata and Litopterna, both native to South America, became extinct at the end of the Pleistocene, around 12,000 years ago.
Laurasiatheria in the context of Unguligrade
Ungulates are members of the diverse clade Euungulata, which primarily consists of large mammals with hooves. Once part of the taxon "Ungulata" along with paenungulates and tubulidentates, as well as several extinct taxa, "Ungulata" has since been determined to be a polyphyletic grouping based on molecular data. As a result, true ungulates have since been reclassified to the newer clade Euungulata in 2001 within the clade Laurasiatheria, while Paenungulata and Tubulidentata have been reclassified to the distant clade Afrotheria. Alternatively, some authors use the name Ungulata to designate the same clade as Euungulata.
Living ungulates are divided into two orders: Perissodactyla including equines, rhinoceroses, and tapirs; and Artiodactyla including cattle, antelope, pigs, giraffes, camels, sheep, deer, and hippopotamuses, among others. Cetaceans such as whales, dolphins, and porpoises are also classified as artiodactyls, although they do not have hooves. Most terrestrial ungulates use the hoofed tips of their toes to support their body weight while standing or moving. Two other orders of ungulates, Notoungulata and Litopterna, both native to South America, became extinct at the end of the Pleistocene, around 12,000 years ago.
Laurasiatheria in the context of Lipotyphla
Lipotyphla is an obsolete order of mammals, meaning lacking blind gut, including the members of the order Eulipotyphla (i.e. the solenodons, family Solenodontidae; hedgehogs and gymnures, family Erinaceidae; desmans, moles, and shrew-like moles, family Talpidae; and true shrews, family Soricidae) as well as three other families of the former order Insectivora, Chrysochloridae (golden moles), Tenrecidae (tenrecs), and Potamogalidae (otter shrews). However, molecular studies found the golden moles, tenrecs, and otter shrews to be unrelated to the others (these afrothere groups were then put in their own order, Afrosoricida). This made Lipotyphla an invalid polyphyletic order and gave rise to the notion of Eulipotyphla instead, an exclusively laurasiathere grouping.
Laurasiatheria in the context of Boreoeutheria
Boreoeutheria (/boʊˌriːoʊjuːˈθɛriə/) is a magnorder of placental mammals that groups together superorders Euarchontoglires and Laurasiatheria. The clade includes groups as diverse as giraffes, pigs, zebras, rhinoceroses, dogs, cats, rabbits, mice, bats, whales, dolphins, and primates (monkeys, apes, and humans).
With a few exceptions, male boreoeutherians have a scrotum, an ancestral feature of the clade. The sub-clade Scrotifera was named after this feature.