Toxodontidae is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

of notoungulate mammals, known from the

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but t ...

to the

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...

(11,000 BP) of South America, with one genus, ''

Mixotoxodon ''Mixotoxodon'' ("mixture ''Toxodon''") is an extinct genus of notoungulate of the family Toxodontidae inhabiting South America, Central America and parts of southern North America during the Pleistocene epoch, from 1,800,000—12,000 years a ...

'', also known from the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

of Central America and southwestern North America (Texas).E. Lundelius, et al. 2013. The first occurrence of a toxodont (Mammalia, Notoungulata) in the United States. ''Journal of Vertebrate Paleontology'', Vol 33, No 1, pp. 229–23
DOI:10.1080/02724634.2012.711405
/ref> They somewhat resembled

rhinoceros A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae. (It can also refer to a member of any of the extinct specie ...

es, and had teeth with high crowns and open roots, suggesting that they often fed on tough

pampas grass Pampas grass or pampas-grass is a common name which may refer to any of several similar-looking, tall-growing species of grass: * Species of '' Cortaderia'' including: :* ''Cortaderia selloana'' and its selected cultivars :* ''Cortaderia jubata'' ( ...

. However, isotopic analyses have led to the conclusion that the most recent forms were grazing and browsing generalists.

Taxonomy

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 In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

to the

perissodactyl Odd-toed ungulates, mammals which constitute the taxonomic order Perissodactyla (, ), are animals—ungulates—who have reduced the weight-bearing toes to three (rhinoceroses and tapirs, with tapirs still using four toes on the front legs) o ...

s. In 2014, a study identifying a new species of toxodontid resolved the families phylogenetic relations. The below cladogram was found by the study:

References

External links

* {{Taxonbar, from=Q846394 Toxodonts Oligocene mammals Miocene mammals of South America Chattian first appearances Holocene extinctions Fossil taxa described in 1845 Taxa named by Richard Owen Pliocene notoungulates Prehistoric mammal families

Taxonomy

References

Further reading

External links