Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as well as many extinct non-marsupial relatives.

Marsupial, any of more than 250 species belonging to the infraclass Metatheria (sometimes called Marsupialia), a mammalian group characterized by premature birth and continued development of the newborn while attached to the nipples in a pouch on the mother’s lower belly.

From deserts and dry scrubland in Australia to tropical rain forests in South America, there are at least a few, and often many, species of Metatheria present. These animals occupy an enormous variety of terrestrial habitats throughout these two continents.

Metatheria (Pouched mammals or marsupials) 1. Ear with pinna. 2. Nipples abdominal. 3. No corpous callosum. 4. Scrotum in font of penis. 5. Digestive and urinogenital tracts open out by separate apertures that are controlled by a common sphincter muscle. 6. Marsupial pouch often present. 7. Viviparous. 8.

Metatherians, which comprise marsupials and their closest fossil relatives, were one of the most dominant clades of mammals during the Cretaceous and are the most diverse clade of living mammals after Placentalia.

Metatheria were widely distributed over many parts of the world as recently as the Miocene period. But they are now confined to the Australian region (except New Zealand), to South America and a few species to North America. 1. Distribution: Almost entirely continued to the Australian region with the exception of the American opossums. 2.

Metatheria is a group in the class Mammalia which contains the marsupials and the sparassodonts. The group was first proposed by Thomas Henry Huxley in 1880. It is nearly synonymous with the earlier taxon Marsupialia, but it also contains the nearest fossil relatives of marsupial mammals.

The diversity and phylogeny of marsupials and their stem relatives (collectively, Metatheria) are reviewed, from their divergence from their sister taxon (Eutheria) and the earliest fossil record of metatherians, to the relationships between and within the seven extant marsupial orders.

Dec 17, 2014 · Metatherians, which comprise marsupials and their closest fossil relatives, were one of the most dominant clades of mammals during the Cretaceous and are the most diverse clade of living mammals after Placentalia.

Jan 1, 2016 · I present a comprehensive overview of our current understanding of the phylogeny of Metatheria, focusing on recent studies that have presented algorithmic analyses of character matrices.