Toxodontidae is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

notoungulate Notoungulata is an extinct order of ungulates that inhabited South America from the early Paleocene to the end of the Pleistocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms re ...

mammals, known from the

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

to the

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

(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 ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

of Central America and southern North America (as far north as Texas). Member of the family were medium to large-sized, ranging from around in ''

Nesodon ''Nesodon'' ("island tooth")Palmer (1904) p. 457. is a genus of Miocene mammal belonging to the extinct order Notoungulata which inhabited southern South America during the Late Oligocene to Miocene living from 29.0 to 16.3 Ma and existed for a ...

'' to in ''

Toxodon ''Toxodon'' (meaning "bow tooth" in reference to the curvature of the teeth) is an extinct genus of large ungulate native to South America from the Pliocene to the end of the Late Pleistocene. ''Toxodon'' is a member of Notoungulata, an order of ...

'', and had medium to high-crowned dentition, which in derived members of the group evolved into ever-growing cheek teeth. Isotopic analyses have led to the conclusion that Pleistocene members of the family were flexible mixed feeders (both

browsing Browsing is a kind of orienting strategy. It is supposed to identify something of relevance for the browsing organism. In context of humans, it is a metaphor taken from the animal kingdom. It is used, for example, about people browsing open sh ...

and

grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to free range (roam around) and consume wild vegetations in order to feed conversion ratio, convert the otherwise indigestible (by human diges ...

Taxonomy

The endemic notoungulate and

litoptern Litopterna (from "smooth heel") is an extinct order of South American native ungulates that lived from the Paleocene to the Pleistocene-Holocene around 62.5 million to 12,000 years ago (or possibly as late as 3,500 years ago), and were also pres ...

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 Perissodactyla (, ), or odd-toed ungulates, is an order of Ungulate, ungulates. The order includes about 17 living species divided into three Family (biology), families: Equidae (wild horse, horses, Asinus, asses, and zebras), Rhinocerotidae ( ...

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 Taxa named by Richard Owen Pliocene notoungulates Prehistoric mammal families

Taxonomy

References

Further reading

External links