Xenarthra is a major clade of placental mammals native to the Americas. There are 31 living species: the anteaters, tree sloths, and armadillos. Extinct xenarthrans include the glyptodonts, pampatheres and ground sloths. Xenarthrans originated in South America during the late Paleocene about 60 million years ago. They evolved and diversified extensively in South America during the continent's long period of isolation in the early to mid Cenozoic Era. They spread to the Antilles by the early Miocene and, starting about 3 million years ago, spread to Central and North America as part of the Great American Interchange. Nearly all of the formerly abundant megafaunal xenarthrans became extinct at the end of the Pleistocene.
Glyptodonts are an extinct clade of large, heavily armoured armadillos, reaching up to 1.5 metres (4.9 ft) in height, and maximum body masses of around 2 tonnes. They had short, deep skulls, a fused vertebral column, and a large bony carapace made up of hundreds of individual scutes. Some glyptodonts had clubbed tails, similar to ankylosaurid dinosaurs.
Cingulata, part of the superorder Xenarthra, is an order of armored New World placental mammals. Dasypodids and chlamyphorids, the armadillos, are the only surviving families in the order. Two groups of cingulates much larger than extant armadillos existed until recently: pampatheriids, which reached weights of up to 200 kg (440 lb) and chlamyphorid glyptodonts, which attained masses of 2,000 kg (4,400 lb) or more.
Peltephilus, the horned armadillo, is an extinct genus of armadillo xenarthran mammals that first inhabited Argentina during the Oligocene epoch, and became extinct in the Miocene epoch. Notably, the scutes on its head were so developed that they formed horns. Aside from the horned gophers of North America, it is the only known fossorial horned mammal. P. ferox had skull about 11.7 centimetres (4.6 in), and estimated body mass is around 11.07 kilograms (24.4 lb).
Hapalops is an extinct genus of ground sloth from the Early to Late Miocene of Brazil, Bolivia, Colombia, and Argentina in South America.
Thoatherium is an extinct genus of litoptern mammals from the Early Miocene of Argentina. Fossils of the genus have been found in the Santa Cruz Formation in Argentina.
Scalabrinitherium is an extinct genus of mammals of the family Macraucheniidae. Fossils of this animal were found among the fossils of prehistoric xenarthrans in the Ituzaingó Formation of Argentina.
Parapropalaehoplophorus septentrionalis was a comparatively small species of glyptodont, extinct relatives of the modern armadillo. The mammal, identified in 2007 from the fossilized remains of a specimen found in 2004, weighed approximately 200 pounds and had a shell covered by tiny circular bumps. It lumbered around northern Chile in the Chucal Formation, an area now dominated by the Andes mountain range, some 18 million years ago. Fossils of the glyptodont also have been found in Peru.
Pampatheriidae is an extinct family of large cingulates related to armadillos. They first appeared in South America during the mid-Miocene, and Holmesina and Pampatherium spread to North America during the Pleistocene after the formation of the Isthmus of Panama as part of the Great American Interchange. They became extinct as part of the end-Pleistocene extinctions, about 12,000 years ago.
Euphractinae is an armadillo subfamily in the family Chlamyphoridae.
Holmesina is a genus of pampathere, an extinct group of armadillo-like xenarthrans that were distantly related to extant armadillos. Like armadillos, and unlike the other extinct branch of megafaunal cingulates, the glyptodonts, the shell was made up of flexible plates which allowed the animal to move more easily. Holmesina species were herbivores that grazed on coarse vegetation; armadillos are mostly insectivorous or omnivorous.
Stegotherium is an extinct genus of long-nosed armadillo, belonging to the Dasypodidae family alongside the nine-banded armadillo. It is currently the only genus recognized as a member of the tribe Stegotheriini. It lived during the Early Miocene of Patagonia and was found in Colhuehuapian rocks from the Sarmiento Formation, Santacrucian rocks from the Santa Cruz Formation, and potentially also in Colloncuran rocks from the Middle Miocene Collón Curá Formation. Its strange, almost toothless and elongated skull indicates a specialization for myrmecophagy, the eating of ants, unique among the order Cingulata, which includes pampatheres, glyptodonts and all the extant species of armadillos.
Chlamyphoridae is a family of cingulate mammals. While glyptodonts have traditionally been considered stem-group cingulates outside the group that contains modern armadillos, there had been speculation that the extant family Dasypodidae could be paraphyletic based on morphological evidence. In 2016, an analysis of Doedicurus mtDNA found it was, in fact, nested within the modern armadillos as the sister group of a clade consisting of Chlamyphorinae and Tolypeutinae. For this reason, all extant armadillos but Dasypus were relocated to a new family.
Kelenkura is an extinct genus of heavily armored mammals belonging to the subfamily Glyptodontinae, from the family Chlamyphoridae that contain most of the modern armadillos. It was a medium-sized South American animal, distantly related to Doedicurus. Fossils of this genus were recovered in the Arroyo Chasicó Formation and in the Loma de Las Tapias Formation of Argentina in rocks dating back to the Late Miocene epoch.
Cullinia is an extinct genus of litoptern, an order of South American native ungulates that included horse-like and camel-like animals such as Macrauchenia. It is only known from fragmentary remains. Cullinia levis is known from Chasicoan remains found in the Arroyo Chasicó Formation of Argentina, and remains from the Brazilian state of Acre and the Huayquerian Ituzaingó Formation have been assigned to Cullinia sp..
Neoglyptatelus is an extinct genus of xenarthran, belonging to the order Cingulata. It lived from the Middle to the Late Miocene, and its fossilized remains are found in South America.
Proeuphractus is an extinct genus of xenarthran, related to the modern armadillos. It lived from the Early to the Late Miocene, and its fossilized remains were discovered in South America.
Dasypus neogaeus is an extinct species of armadillo, belonging to the genus Dasypus, alongside the modern nine-banded armadillo. The only known fossil is a single osteoderm, though it has been lost, that was found in the Late Miocene strata of Argentina.
Chasicobradys is an extinct genus of ground sloths of the family Nothrotheriidae that lived in what is now Argentina. Chasicobradys was discovered in the Arroyo Chasicó Formation, in Buenos Aires Province. It is only known from jaw fragments and teeth, which allowed the identification of this species, and was classified as a member of the nothrotheriid subfamily Nothrotheriinae, which comprises small to medium-sized species of ground sloths.
Peltephilidae is a family of South American cingulates (armadillos) that lived for over 40 million years, but peaked in diversity towards the end of the Oligocene and beginning of the Miocene in what is now Argentina. They were exclusive to South America due to its geographic isolation at the time, one of many of the continent's strange endemic families. Peltephilids are one of the earliest known cingulates, diverging from the rest of Cingulata in the Early Eocene.
