Microbiotheria, also known as the small opossum and the micro mammals, is an order under the marsupiala, under which there is only the micro mammals.Most of the species under this order have been extinct, leaving only the South Dragon.
The oldest known microfauna member is Khasia cordillensis, whose fossils were found in the Paleocene strata of Bolivia.In addition, several genera were discovered from the Paleogene and Neogene strata in South America.A large number of middle Eocene fossil teeth found on Seymour Island in western Antarctica may belong to the order of microfauna.It is also reported that microfossils belonging to early Eocene microfossils have been found in northwest Australia, but they are not described.If they really belong to, they can provide important evolutionary and biogeographical data.[1]
Originally thought to belong to opossum, but anatomical and genetic research results show that they are self serving and close to Australian marsupials.The microfauna and Australian marsupials also form Australian marsupials.
In South America, Antarctica and AustraliaGondwanaThe ancestors of the South Dragon believed that they had originally stayed in South America, or followed other fauna from Australia to South America.[1]
