| Pelecyodon | |
|---|---|
 | |
| Skull of Pelecyodon cristatus | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Pilosa |
| Superfamily: | Megatherioidea |
| Genus: | † Pelecyodon Ameghino 1891 |
| Species | |
| |
Pelecyodon is an extinct genus of ground sloths from the Early Miocene (Santacrucian) of South America. Fossils have been found in the Santa Cruz Formation in Argentina. [1] [2]
Mylodontidae is a family of extinct South American and North American ground sloths within the suborder Folivora of order Pilosa, living from around 23 million years ago (Mya) to 11,000 years ago. This family is most closely related to another family of extinct ground sloths, Scelidotheriidae, as well as to the extant arboreal two-toed sloths, family Choloepodidae; together these make up the superfamily Mylodontoidea. Phylogenetic analyses based on morphology uncovered the relationship between Mylodontidae and Scelidotheriidae; in fact, the latter was for a time considered a subfamily of mylodontids. However, molecular sequence comparisons were needed for the correct placement of Choloepodidae. These studies have been carried out using mitochondrial DNA sequences as well as with collagen amino acid sequences. The latter results indicate that Choloepodidae is closer to Mylodontidae than Scelidotheriidae is. The only other living sloth family, Bradypodidae, belongs to a different sloth radiation, Megatherioidea.
Megalonychidae is an extinct family of sloths including the extinct Megalonyx. Megalonychids first appeared in the early Oligocene, about 35 million years (Ma) ago, in southern Argentina (Patagonia). There is actually one possible find dating to the Eocene, about 40 Ma ago, on Seymour Island in Antarctica. They first reached North America by island-hopping across the Central American Seaway, about 9 million years ago, prior to formation of the Isthmus of Panama about 2.7 million years ago. Some megalonychid lineages increased in size as time passed. The first species of these were small and may have been partly tree-dwelling, whereas the Pliocene species were already approximately half the size of the huge Late Pleistocene Megalonyx jeffersonii from the last ice age.
Hapalops is an extinct genus of ground sloth from the Early to Late Miocene of Brazil, Bolivia, Colombia, and Argentina in South America.
Chubutherium is an extinct genus of ground sloth from the Late Oligocene and Early Miocene of Chubut Province, Argentina.
Imagocnus is an extinct genus of ground sloth from the Early Miocene (Burdigalian) Lagunitas Formation of Cuba.
Thalassocnus is an extinct genus of semiaquatic ground sloths from the Miocene and Pliocene of the Pacific South American coast. It is monotypic within the subfamily Thalassocninae. The five species—T. antiquus, T. natans, T. littoralis, T. carolomartini, and T. yuacensis—represent a chronospecies, a population gradually adapting to marine life in one direct lineage. They are the only known aquatic sloths. They have been found in the Pisco Formation of Peru and the Bahía Inglesa, Coquimbo, and Horcón formations of Chile. Thalassocninae has been placed in both the families Megatheriidae and Nothrotheriidae.
Octomylodon is an extinct genus of ground sloth of the family Mylodontidae, living during the Late Miocene (Huayquerian). Fossil remains of Octomylodon have been found uniquely in the Ituzaingó Formation, Argentina, South America from 9.0 to 6.8 mya, existing for approximately 2.2 million years.
Octodontotherium is an extinct genus of ground sloth of the family Mylodontidae, endemic to South America during the Oligocene-Early Miocene (Deseadan). It lived from 29 to 21 mya, existing for approximately 8 million years.
Mylodontinae is a subfamily of the Mylodontidae, an extinct family of ground sloths that lived from the Middle Miocene to the Early Holocene epochs.
Hiskatherium is an extinct genus of small ground sloth from the Middle Miocene Honda Group of Bolivia. The type species H. saintandrei was named in 2011 on the basis of a lower jaw. Although it has not been placed in a specific family, Hiskatherium is similar to the extinct sloths Hapalops and Xyophorus.
Nothrotheriidae is a family of extinct ground sloths that lived from approximately 11.6 mya—11,000 years ago, existing for approximately 11.49 million years. Previously placed within the tribe Nothrotheriini or subfamily Nothrotheriinae within Megatheriidae, they are now usually placed in their own family, Nothrotheriidae. Nothrotheriids appeared in the Tortonian, some 11.6 million years ago, in South America. The group includes the comparatively slightly built Nothrotheriops, which reached a length of about 2.75 metres (9.0 ft). While nothrotheriids were small compared to some of their megatheriid relatives, their claws provided an effective defense against predators, like those of larger anteaters today.
Nematherium is an extinct genus of ground sloth of the family Scelidotheriidae found in Argentina and Chile during the Middle Miocene epoch (Santacrucian). Fossils have been found in the Cura-Mallín Formation of Chile and the Santa Cruz and Sarmiento Formations of Argentina.
Eionaletherium is an extinct genus of ground sloth from the Late Miocene coasts of Venezuela containing one species: E. tanycnemius.
Megatheriinae is a subfamily of the Megatheriidae, an extinct family of ground sloths that lived from the Middle Miocene to the Early Holocene.
Proscelidodon is an extinct genus of ground sloths in the family Scelidotheriidae. It lived during the Miocene and Pliocene of what is now Argentina and Bolivia. The genus was described in 1935.
Mcdonaldocnus is an extinct genus of nothrotheriid ground sloths that lived during the Middle Miocene and Early Pliocene of what is now Bolivia and Argentina. It was originally placed in the genus Xyophorus but was subsequently recognized as a distinct genus by Gaudin and colleagues in 2022. The authors reassigned the material of "Xyophorus" bondesioi, "Xyophorus" villarroeli and Xyophorus sp. to Mcdonaldocnus.
Urumacotherium is an extinct genus of ground sloths of the family Mylodontidae. It lived from the Middle Miocene to the Early Pliocene of what is now Brazil, Peru and Venezuela.
Prepoplanops is an extinct genus of ground sloth of the family Megatheriidae. It lived in the Miocene around 18 to 16 million years ago of what is now Argentina. The only known species is Prepoplanops boleadorensis.
Huilabradys is an extinct genus of ground sloths of the family Nothrotheriidae that lived in what is now Colombia. Huilabradys was discovered in the strata of the La Tatacoa desert in the Huila department, in the Villavieja Formation, and is part of the so-called La Venta fauna, a fossiliferous location from the mid-Miocene period that has provided a notable paleontological contribution on the Miocene faunas of northern South America. The remains discovered are basically fragments of the jaws and teeth, allowed the identification of this species, whose only species is Huilabradys magdaleniensis, and was classified as a member of the nothrotheriid subfamily Nothrotheriinae, which comprises small to medium-sized species of ground sloths.
Neonematherium is an extinct genus of scelidotheriid ground sloths that lived in Argentina, Chile, and Colombia during the Early to Late Miocene. Fossils have been found in the Honda Group of Colombia, and the Río Frías Formation of Chile.
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