Toxodontidae is an extinct family of notoungulate mammals, known from the Oligocene to the Holocene (11,000 BP) of South America,[1] with one genus, Mixotoxodon, also known from the Pleistocene of Central America and southern North America (as far north as Texas).[2] Member of the family were medium to large-sized,[3] ranging from around 350–400 kilograms (770–880 lb) in Nesodon to 1,000–1,200 kilograms (2,200–2,600 lb) in Toxodon,[4] and had medium to high-crowned dentition, which in derived members of the group evolved into ever-growing cheek teeth.[5] Isotopic analyses have led to the conclusion that Pleistocene members of the family were flexible mixed feeders (both browsing and grazing).[6][7]
Toxodontidae | |
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Toxodon platensis | |
Skeleton of Nesodon imbricatus | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | †Notoungulata |
Clade: | †Eutoxodontia |
Family: | †Toxodontidae Owen 1845 |
Subfamilies and genera | |
†Haplodontheriinae
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The endemic notoungulate and litoptern ungulates of South America have been shown by studies of collagen and mitochondrial DNA sequences to be a sister group to the perissodactyls.[8][9][10]
In 2014, a study identifying a new species of toxodontid resolved the families phylogenetic relations. The below cladogram was found by the study:[11]
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