Litopterna

Litopterna Temporal range: Paleocene–Holocene PreꞒ Ꞓ O S D C P T J K Pg N
Skeleton of Macrauchenia (Macraucheniidae)
Skeleton of Diadiaphorus (Proterotheriidae)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Clade:	Panperissodactyla
Order:	†Litopterna Ameghino 1889
Subgroups
†Didolodontidae? †Notonychopidae †Protolipternidae †Sparnotheriodontidae †Indaleciidae †Lopholipterna †Proterotherioidea †Proterotheriidae †Macrauchenioidea †Adianthidae †Macraucheniidae

Litopterna (from Ancient Greek: λῑτή πτέρνα "smooth heel") is an extinct order of South American native ungulates that lived from the Paleocene to the end of the Pleistocene-early Holocene around 63 million-12,000 years ago, and were also present in Antarctica during the Eocene. They represent the second most diverse group of South American ungulates after Notoungulata.^[1] It is divided into nine families, with Proterotheriidae and Macraucheniidae being the most diverse and last surviving families.^[2]