Eutheria
You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.
| Placental mammals/Eutheria Fossil range: Middle Cretaceous - Recent | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
 House Mouse, Mus musculus
| ||||||||||
| Scientific classification | ||||||||||
| ||||||||||
| Orders[1] | ||||||||||
|
Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [1] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.
Overview
Eutheria[1] is a taxon containing the placental mammals, such as humans. The sister group of Eutheria is Metatheria, which includes marsupials and their extinct relatives.
Origin of the word
The name Eutheria comes from the 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 eggs which protect developing young until they are fully developed. Marsupials give birth to partially-developed young who then migrate to a special 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 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
Extant mammal orders by infraclass |
|---|
Metatheria: Didelphimorphia · Paucituberculata · Microbiotheria · Notoryctemorphia · Dasyuromorphia · Peramelemorphia · Diprotodontia Eutheria: Afrosoricida · Macroscelidea · Tubulidentata · Hyracoidea · Proboscidea · Sirenia · Cingulata · Pilosa · Scandentia · Dermoptera · Primates · Rodentia · Lagomorpha · Erinaceomorpha · Soricomorpha · Chiroptera · Pholidota · Carnivora · Perissodactyla · Artiodactyla · Cetacea |
Notes and references
Detailed cladogram of Eutheria from Proceedings of the National Academy of Sciences, February 4, 2003, vol. 100, no. 3, pp. 1056-1061. bg:Плацентни ca:Euteri cs:Placentálové de:Höhere Säugetiere eo:Placentulojfr:Placentalia hr:Viši sisavci hu:Méhlepényesek id:Eutheria it:Eutheria ja:真獣下綱 ko:진수하강 lb:Héijer Mamendéieren lij:Placentalia nl:Placentadieren no:Placentale pattedyr oc:Eutheriasl:Višji sesalci sv:Högre däggdjur th:ยูเธอเรียzh-yue:真獸亞綱
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
