Mylodontidae is a family of extinct South American and North American

ground sloth Ground sloths are a diverse group of extinct sloths in the mammalian superorder Xenarthra. The term is used to refer to all extinct sloths because of the large size of the earliest forms discovered, compared to existing tree sloths. The Caribbe ...

s within the suborder

Folivora Sloths are a group of Neotropical xenarthran mammals constituting the suborder Folivora, including the extant arboreal tree sloths and extinct terrestrial ground sloths. Noted for their slowness of movement, tree sloths spend most of their li ...

of order

Pilosa The order Pilosa is a clade of xenarthran placental mammals, native to the Americas. It includes the anteaters and sloths (which includes the extinct ground sloths). The name comes from the Latin word for "hairy". Origins and taxonomy The b ...

, 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 Scelidotheriidae is a family of extinct ground sloths within the order Pilosa, suborder Folivora and superfamily Mylodontoidea, related to the other extinct mylodontoid family, Mylodontidae, as well as to the living two-toed sloth family Choloe ...

, as well as to the extant

arboreal Arboreal locomotion is the Animal locomotion, locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. Th ...

two-toed sloths, family Choloepodidae; together these make up the superfamily

Mylodontoidea Sloths are a group of Neotropical xenarthran mammals constituting the suborder Folivora, including the extant arboreal tree sloths and extinct terrestrial ground sloths. Noted for their slowness of movement, tree sloths spend most of their li ...

Phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

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 Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...

sequences as well as with

collagen Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole ...

amino acid sequences. The latter results indicate that Choloepodidae is closer to Mylodontidae than Scelidotheriidae is. The only other living sloth family, Bradypodidae (three-toed sloths), belongs to a different sloth radiation,

Megatherioidea Sloths are a group of Neotropical xenarthran mammals constituting the suborder Folivora, including the extant arboreal tree sloths and extinct terrestrial ground sloths. Noted for their slowness of movement, tree sloths spend most of their li ...

. The mylodontoids form one of three major radiations of sloths. The discovery of their fossils in caverns associated with human occupation lead some early researchers to theorize that the early humans built

corral A pen is an enclosure for holding livestock. It may also perhaps be used as a term for an enclosure for other animals such as pets that are unwanted inside the house. The term describes types of enclosures that may confine one or many animal ...

s when they could procure a young ground sloth, to raise the animal to butchering size.Woodward (1900) However, radiocarbon dates do not support simultaneous occupation of the site by humans and sloths.

Subfossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

remains like coproliths, fur and skin have been discovered in some quantities.

Phylogeny

The following sloth family phylogenetic tree is based on collagen and mitochondrial DNA sequence data (see Fig. 4 of Presslee ''et al''., 2019).

References

Bibliography

*Woodward, A.S. (1900): On some remains of Grypotherium (Neomylodon) listai and associated mammals from a cavern near Consuelo Cove, Last Hope Inlet. ''Proceedings of the Zoological Society of London'', 1900(5): 64-79.

External links

* Sloth World: An Online Sloth Bibliography

* ttps://web.archive.org/web/20060823122149/http://www.acnatsci.org/museum/leidy/paleo/megalonyx.html Academy of Natural Sciences ground sloth page
Illinois State Museum ground sloth page

''Eremotherium'' in Florida

Western Center for Archaeology and Paleontology
Hemet, CA {{Taxonbar, from=Q1749282 Neogene mammals of South America Quaternary mammals of South America Rupelian first appearances Holocene extinctions Prehistoric mammal families Taxa named by Florentino Ameghino

Phylogeny

References

Bibliography

Further reading

External links