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Multituberculata
Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct taxon of rodent-like mammals that existed for approximately one hundred and twenty million years —the second longest fossil history of any mammal lineage, after Haramiyida— but eventually declined from the late Palaeocene onwards, disappearing in the early Oligocene,〔 though they might have lived even longer into the Miocene, if gondwanatheres are part of this group. At least 200 species are known, ranging from mouse-sized to beaver-sized. These species occupied a diversity of ecological niches, ranging from burrow-dwelling to squirrel-like arborealism.〔Weil 1997〕 Multituberculates are usually placed outside either of the two main groups of living mammals—Theria, including placentals and marsupials, and Monotremata〔Agustí-Antón 2002, pp 3-4〕—but closer to Theria than to monotremes.〔Benton, Michael J. ''Vertebrate Palaeontology'' (2004), (p. 300 )〕〔Carrano, Matthew T., and Richard W. Blob, Timothy J. Gaudin, and John R. Wible (2006). ''Amniote Paleobiology: Perspectives on the Evolution of Mammals, Birds, and Reptiles'', (p. 358 ).〕
==History==
The multituberculates existed for about 120 million years, and are often considered the most successful, diversified, and long-lasting mammals in natural history.〔 They first appeared in the Jurassic, or perhaps even the Triassic, survived the mass extinction in the Cretaceous, and became extinct in the early Oligocene epoch, some 35 million years ago.〔 The oldest known species in the group is ''Rugosodon eurasiaticus'' from the Jurassic of eastern China, some 160 million years ago, and the youngest are two species, ''Ectypodus lovei'' and an unnamed possible neoplagiaulacid, from the late Eocene/Oligocene Medicine Pole Hills deposits of North Dakota.〔 (Abstract )〕 If gondwanatheres are multituberculates, then the clade might have survived even longer into the Colhuehuapian Miocene in South America, in the form of ''Patagonia peregrina''.〔
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