Placentalia

Placental mammals; Temporal range: Paleocene-Holocene Possible Late Cretaceous record
	Placentals from different orders.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Clade:	Eutheria
Infraclass:	Placentalia; Owen, 1837
Subgroups
	Atlantogenata Afrotheria; Xenarthra; ; Boreoeutheria Euarchontoglires; Laurasiatheria; ; For extinct groups, see text

Placental mammals (infraclass Placentalia /plæsənˈteɪliə/) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguished from monotremes and marsupials in that the fetus is carried in the uterus of its mother to a relatively late stage of development. The name is something of a misnomer considering that marsupials also nourish their fetuses via a placenta,^[1] though for a relatively briefer period, giving birth to less developed young which are then nurtured for a period inside the mother's pouch. Placentalia represents the only living group within Eutheria, which contains all mammals more closely related to placentals than to marsupials.

^ Renfree, M. B. (March 2010). "Review: Marsupials: placental mammals with a difference". Placenta. 31 Supplement: S21–6. doi:10.1016/j.placenta.2009.12.023. PMID 20079531.

[Renfree2010-1] Renfree, M. B. (March 2010). "Review: Marsupials: placental mammals with a difference". Placenta. 31 Supplement: S21–6. doi:10.1016/j.placenta.2009.12.023. PMID 20079531.

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