<Ul> <Li> Microbiotheria </Li> <Li> Dasyuromorphia </Li> <Li> Peramelemorphia </Li> <Li> Notoryctemorphia </Li> <Li> Diprotodontia </Li> <Li> † Yalkaparidontia </Li> </Ul> <Tr> <Td_colspan="2"> Present - day distribution of marsupials . </Td> </Tr> <P> Marsupials are any members of the mammalian infraclass Marsupialia . All extant marsupials are endemic to Australasia and the Americas . A distinctive characteristic common to these species is that most of the young are carried in a pouch . Well - known marsupials include kangaroos, wallabies, koalas, possums, opossums, wombats, and Tasmanian devils . Some lesser - known marsupials are the potoroo and the quokka . </P> <P> Marsupials represent the clade originating from the last common ancestor of extant metatherians . Like other mammals in the Metatheria, they give birth to relatively undeveloped young that often reside in a pouch located on their mothers' abdomen for a certain amount of time . Close to 70% of the 334 extant species occur on the Australian continent (the mainland, Tasmania, New Guinea and nearby islands). The remaining 100 are found in the Americas--primarily in South America, but thirteen in Central America, and one in North America, north of Mexico . </P>

Mammals of the order marsupialia have what unique feature
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