| Microbiotheriidae | |
|---|---|
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| Dromiciops gliroides | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Infraclass: | Marsupialia |
| Superorder: | Australidelphia |
| Order: | Microbiotheria |
| Family: | Microbiotheriidae Ameghino, 1887 |
| Type genus | |
| Microbiotherium† Ameghino, 1887 | |
| Genera | |
Microbiotheriidae is afamily ofaustralidelphian marsupials represented by only one extant species, themonito del monte, and a number of extinct species known from fossils inSouth America,Western Antarctica, and northeasternAustralia.[1]
Microbiotheriids were once thought to be members of the orderDidelphimorphia (which contains theVirginia opossum); however, an accumulation of bothanatomical andgenetic evidence in recent years has led to the conclusion that microbiotheriids and othermicrobiotheres are not didelphids at all, but are instead most closely related to the Australasian marsupials; together, the microbiotheres and the Australian orders form the cladeAustralidelphia which are now thought to have first evolved in the South American region ofGondwana.
The oldest microbiotheriid and microbiothere currently recognised isKhasia cordillerensis, based onfossil teeth from Early Palaeocene deposits atTiupampa,Bolivia. Numerous genera are known from various Palaeogene and Neogene fossil sites in South America. A number of possible microbiotheres, again represented by isolated teeth, have also been recovered from the MiddleEoceneLa Meseta Formation ofSeymour Island, Western Antarctica. Finally, several undescribed microbiotheres have been reported from the Early Eocene Tingamarra Local Fauna in northeastern Australia; if this is indeed the case, then these Australian fossils have important implications for understanding marsupial evolution andbiogeography. The distant ancestors of themonito del monte, it is thought, remained in what is now South America while others enteredAntarctica and eventuallyAustralia during the time when all threecontinents were joined as part of Gondwana.[2][3]
Dromiciops is thought to have evolved from members of the genusMicrobiotherium, known from the early Miocene of South America, with some authors considering the genera indistinguishable. All other genera, likePachybiotherium, had become extinct by the late Miocene.[4]
Authority control databases: National |
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