Eutheria
216676
224479431
2008-07-09T00:57:37Z
Thijs!bot
1392310
robot Adding: [[fi:Istukkanisäkkäät (osaluokka)]]
{{Disputed|date=March 2008}}
{{Expand|date=January 2007}}
{{Taxobox
| name = Placental mammals / Eutheria
| fossil_range = Early [[Cretaceous]] - Recent
| image = house_mouse.jpg
| image_width = 270px
| image_caption = [[House Mouse]], ''Mus musculus''
| regnum = [[Animal]]ia
| phylum = [[Chordate|Chordata]]
| classis = [[Mammal]]ia
| subclassis = [[Theria]]
| infraclassis = '''Eutheria'''
| infraclassis_authority = [[Thomas Henry Huxley]], [[1880]]
| subdivision_ranks = Orders<ref>{{cite web|title=Eutheria phylogeny|work=Mikko's Phylogeny Archive|accessdate=2006-03-08|url=http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/Synapsida/Eutheria/Eutheria_1.htm#Edentata}}</ref>
| subdivision =
*''[[Bobolestes]]''
*''[[Eomaia]]''
*''[[Maelestes]]''
*''[[Montanalestes]]''
*''[[Murtoilestes]]''
*''[[Prokennalestes]]''
*'''Placentalia'''
**Superorder '''[[Xenarthra]]:'''
***[[Cingulata]] (Armadillos)
***[[Pilosa]] (Sloths, True Anteaters)
**Superorder '''[[Laurasiatheria]]:'''
***[[Pholidota]] (Scaly Anteaters)
***[[Soricomorpha]] (Moles, Shrews)
***[[Erinaceomorpha]] (Hedgehogs)
***[[Perissodactyla]] (Horses, Rhinoceroses and Tapirs)
***[[Cetartiodactyla]] (Bovids, Pigs, Cervids, Camels, Whales, Dolphins)
***[[Carnivora]] (Cats, Dogs, Bears, Seals)
***[[Chiroptera]] (Bats)
***†[[Meridiungulata]]
***†[[Condylarthra]]
***†[[Dinocerata]]
***†[[Mesonychia]]
***†[[Cimolesta]]
***†[[Creodonta]]
**Superorder '''[[Afrotheria]]:'''
***[[Afrosoricida]] (Tenrecs)
***[[Hyracoidea]] (Hyraxes)
***[[Macroscelidea]] (Elephant Shrews)
***[[Proboscidea]] (Elephants)
***[[Sirenia]] (Manatees, Dugongs)
***[[Tubulidentata]] (Aardvark)
***†[[Embrithopoda]]
***†[[Desmostylia]]
**Superorder '''[[Euarchontoglires]]:'''
***[[Dermoptera]] (Colugos)
***[[Lagomorpha]] (Rabbits, Hares)
***[[Primates]] (Apes, Monkeys)
***†[[Plesiadapiformes]]
***[[Rodent]]ia (Rodents)
***[[Scandentia]] (Treeshrews)
}}
'''Eutheria'''<ref name="Placentalia">Today [[Placentalia]] and Eutheria are sometimes considered to be the same group. But there are proposals of classification (McKenna & Bell, 1997) that differentiate between the two groups.</ref> is a [[taxon]] containing the [[placenta]]l [[mammal]]s, such as [[human]]s. The [[sister group]] of Eutheria is [[Metatheria]], which includes [[marsupial]]s and their extinct relatives.
==Origin of the word==
The name Eutheria comes from the [[Greek (language)|Greek]] words ''eu-'' "well[-developed]" and ''ther'' "beast". When Eutheria was introduced by [[Thomas Henry Huxley]] in [[1880]], he meant it to be broader in definition than its precursor '''Placentalia'''. Some use Eutheria as a [[total group]] which includes the [[crown group]] Placentalia and extinct mammals which are closer to Placentalia than to [[Marsupialia]].
==Characteristics of eutherians==
Nevertheless, all living eutherians are placental mammals. This means that a eutherian [[fetus]] is nourished during gestation by a [[placenta]]. Eutherians are also [[viviparous]], meaning that the offspring are carried in the mother's [[uterus]] until fully developed.
==Differences from other mammals==
Because of this, eutherians are different from other mammal groups such as [[monotremes]] and [[marsupials]] which are not placental. Monotremes, for instance, lay [[Egg (biology)|eggs]] which protect developing young until they are fully developed. Marsupials give birth to partially-developed young who then migrate to a special [[pouch (marsupial)|pouch]] in the mother's body in which the young continue their development. (Some exceptions do exist. [[Bandicoots]] for instance, which are marsupials, develop small placenta-like structures during gestation.)
==Earliest example==
The earliest known eutherian species is the extinct ''[[Eomaia|Eomaia scansoria]]'' from the Lower [[Cretaceous]] of [[China]]. It is a member of Eutheria, but the hips of the animal were too narrowly built to have allowed the birth of well-developed young. Thus it is unlikely that a placenta greatly contributed to the development of ''E. scansoria's'' young before they were born.
Members of Eutheria are found on all continents and in all oceans.
==See also==
*[[List of placental mammals]]
*[[Mammal]] for classification.
*[[Theria]]
===Compare and contrast===
*[[Metatheria]]
*[[Prototheria]]
{{wikispecies|Eutheria}}
==Notes and references==
Detailed [[cladogram]] of [[extant]] Placentalia from [http://www.pnas.org/content/vol100/issue3/images/large/pq0334222002.jpeg Proceedings of the National Academy of Sciences], February 4, 2003, vol. 100, no. 3, pp. 1056-1061.
<references />
{{Mammals}}
[[Category:Mammals]]
[[bg:Плацентни]]
[[ca:Euteri]]
[[cs:Placentálové]]
[[de:Höhere Säugetiere]]
[[es:Placentalia]]
[[eo:Placentuloj]]
[[fr:Placentalia]]
[[ko:진수하강]]
[[hr:Viši sisavci]]
[[id:Eutheria]]
[[it:Eutheria]]
[[lb:Héijer Mamendéieren]]
[[lij:Placentalia]]
[[hu:Méhlepényesek]]
[[nl:Placentadieren]]
[[ja:真獣下綱]]
[[no:Placentale pattedyr]]
[[oc:Eutheria]]
[[pl:Łożyskowce]]
[[pt:Placentários]]
[[ro:Eutheria]]
[[ru:Плацентарные]]
[[sl:Višji sesalci]]
[[fi:Istukkanisäkkäät (osaluokka)]]
[[sv:Högre däggdjur]]
[[th:ยูเธอเรีย]]
[[zh-yue:真獸亞綱]]
[[zh:真獸下綱]]