Diversity of the

American Marsupials


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Origin
Morphology
Australian Marsupials
American Marsupials
Ecology
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Introduction.

Order: Didelphimorphia.

Order: Paucituberculata.

Order: Microbiotheria

This order consists of a single species, Dromiciops gliroides, at first considered just an unusual opossum. It is found only in the wet forests of Chile and Argentina today. Dromiciops is a semi-arboreal organism which feeds mostly on insects and their larvae.

Microbiotheria (11K)
Dromiciops gliroides

There are numerous related genera known from the Palaeocene and Neocene in South America following a modest adaptive radiation of the order, before this dwindled to the single living species today. There are fossil forms found in Murgon, Australia, dating 55 million years old, which may represent a microbiotherian 'immigrant', and younger isolated teeth from the middle Eocene have been found on Seymour Island, Antarctica. Due to these finds, it is believed that microbiotherians may be an evolutionary link between the American and either some or all of the Australian marsupials. There are 2 hypotheses; either some individuals of the order remained in South America whilst others entered Antarctica and Australia whilst they were still joined as Gondwana, or they were part of an Australian fauna which reinvaded South America.

Order: Sparassodonta.

Order: Groeberida.

Order: Argyrolagida.