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Sloth
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 lives hanging upside down in the trees of the tropical rainforests of South America and Central America. Sloths are considered to be most closely related to anteaters, together making up the xenarthran order Pilosa. There are six extant sloth species in two genera – '' Bradypus'' (three–toed sloths) and '' Choloepus'' (two–toed sloths). Despite this traditional naming, all sloths have three toes on each rear limb-- although two-toed sloths have only two digits on each forelimb. The two groups of sloths are from different, distantly related families, and are thought to have evolved their morphology via parallel evolution from terrestrial ancestors. Besides the extant species, many species of ground sloths ranging up to the size of ele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phyllophaga (mammal)
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 lives hanging upside down in the trees of the tropical rainforests of South America and Central America. Sloths are considered to be most closely related to anteaters, together making up the xenarthran order Pilosa. There are six extant sloth species in two genera – '' Bradypus'' (three–toed sloths) and '' Choloepus'' (two–toed sloths). Despite this traditional naming, all sloths have three toes on each rear limb-- although two-toed sloths have only two digits on each forelimb. The two groups of sloths are from different, distantly related families, and are thought to have evolved their morphology via parallel evolution from terrestrial ancestors. Besides the extant species, many species of ground sloths ranging up to the size of ele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Choloepus Hoffmanni
Hoffmann's two-toed sloth (''Choloepus hoffmanni''), also known as the northern two-toed sloth is a species of sloth from Central and South America. It is a solitary, largely nocturnal and arboreal animal, found in mature and secondary rainforests and deciduous forests. The common name commemorates the German naturalist Karl Hoffmann. Description Hoffmann's two-toed sloth is a heavily built animal with shaggy fur and slow, deliberate movements. The fore feet have only two toes, each ending with long, curved claws, although three clawed toes are on each of the hind feet. Other features that distinguish it from three-toed sloths, which may be found in the same geographic areas, include the longer snout, separate rather than partially fused toes of the forefeet, the absence of hair on the soles of the feet, and larger overall size. The wrist of the sloth has developed some specific traits due to their slow, yet acrobatic motions. These evolved traits include diminution and di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three-toed Sloth
The three-toed or three-fingered sloths are arboreal neotropical mammals . They are the only members of the genus ''Bradypus'' and the family Bradypodidae. The four living species of three-toed sloths are the brown-throated sloth, the maned sloth, the pale-throated sloth, and the pygmy three-toed sloth. In complete contrast to past morphological studies, which tended to place ''Bradypus'' as the sister group to all other folivorans, molecular studies place them nested within the sloth superfamily Megatherioidea, making them the only surviving members of that radiation. Extant species Evolution A study of mitochondrial cytochrome b and 16S rRNA sequences suggests that '' B. torquatus'' diverged from '' B. variegatus'' and '' B. tridactylus'' about 12 million years ago, while the latter two split 5 to 6 million years ago. The diversification of ''B. variegatus'' lineages was estimated to have started 4 to 5 million years ago. Relation to the two-toed sloth Both types of sloth t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Caribbean ground sloths, the most recent survivors, lived in the Antilles, possibly until 1550 BCE. However, radiocarbon dating suggests an age of between 2819 and 2660 BCE for the last occurrence of ''Megalocnus'' in Cuba. Ground sloths had been extinct on the mainland of North and South America for 10,000 years or more. They survived 5,000–6,000 years longer in the Caribbean than on the American mainland, which correlates with the later colonization of this area by humans. Much ground sloth evolution took place during the late Paleogene and Neogene of South America, while the continent was isolated. At their earliest appearance in the fossil record, the ground sloths were already distinct at the family level. The presence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three-toed Sloth
The three-toed or three-fingered sloths are arboreal neotropical mammals . They are the only members of the genus ''Bradypus'' and the family Bradypodidae. The four living species of three-toed sloths are the brown-throated sloth, the maned sloth, the pale-throated sloth, and the pygmy three-toed sloth. In complete contrast to past morphological studies, which tended to place ''Bradypus'' as the sister group to all other folivorans, molecular studies place them nested within the sloth superfamily Megatherioidea, making them the only surviving members of that radiation. Extant species Evolution A study of mitochondrial cytochrome b and 16S rRNA sequences suggests that '' B. torquatus'' diverged from '' B. variegatus'' and '' B. tridactylus'' about 12 million years ago, while the latter two split 5 to 6 million years ago. The diversification of ''B. variegatus'' lineages was estimated to have started 4 to 5 million years ago. Relation to the two-toed sloth Both types of sloth t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bradypus Variegatus
The brown-throated sloth (''Bradypus variegatus'') is a species of three-toed sloth found in the Neotropical realm of Central and South America. It is the most common of the four species of three-toed sloth, and is found in the forests of South and Central America. Description The brown-throated sloth is of similar size and build to most other species of three-toed sloths, with both males and females being in total body length. The tail is relatively short, only long. Adults weigh from , with no significant size difference between males and females. Each foot has three fingers, ending in long, curved claws, which are long on the fore feet, and on the hind feet. The head is rounded, with a blunt nose and inconspicuous ears. As with other sloths, the brown-throated sloth has no incisor or canine teeth, and the cheek teeth are simple and peg-like. They have no gall bladder, cecum, or appendix. The brown-throated sloth has grayish-brown to beige-color fur over the body, wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-toed Sloth
''Choloepus'' is a genus of xenarthran mammals of Central and South America within the monotypic family Choloepodidae, consisting of two-toed sloths, sometimes also called two-fingered sloths. The two species of ''Choloepus'' (which means "lame foot"), Linnaeus's two-toed sloth (''Choloepus didactylus'') and Hoffmann's two-toed sloth (''Choloepus hoffmanni''), were formerly believed on the basis of morphological studies to be the only surviving members of the sloth family Megalonychidae, but have now been shown by molecular results to be closest to extinct ground sloths of the family Mylodontidae. Extant species Evolution A study of retrovirus and mitochondrial DNA suggests that ''C. didactylus'' and ''C. hoffmani'' diverged 6 to 7 million years ago. Furthermore, based on cytochrome c oxidase subunit I sequences, a similar divergence date ( years ago) between the two populations of ''C. hofmanni'' separated by the Andes has been reported. Their ancestors evolved with mari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mylodontidae
Mylodontidae is a family of extinct South American and North American ground sloths within the suborder Folivora 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, as well as to the extant arboreal two-toed sloths, family Choloepus, 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 car ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megatheriidae
Megatheriidae is a family of extinct ground sloths that lived from approximately 23 mya—11,000 years ago. Megatheriids appeared during the Late Oligocene (Deseadan in the SALMA classification), some 29 million years ago, in South America. The group includes the heavily built '' Megatherium'' (given its name 'great beast' by Georges Cuvier) and ''Eremotherium''. An early genus that was originally considered a megatheriid, the more slightly built ''Hapalops'', reached a length of about . The nothrotheres have recently been placed in their own family, Nothrotheriidae. The skeletal structure of these ground sloths indicates that the animals were massive. Their thick bones and even thicker joints (especially those on the hind legs) gave their appendages tremendous power that, combined with their size and fearsome claws, provided a formidable defense against predators. The earliest megatheriid in North America was ''Sibotherium'' which arrived 5.3 million years ago, after cros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nothrotheriidae
Nothrotheriidae is a family of extinct ground sloths that lived from approximately 17.5 mya—10,000 years ago, existing for approximately . 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 Burdigalian, some 19.8 million years ago, in South America. The group includes the comparatively slightly built ''Nothrotheriops'', which reached a length of about . 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. Evolution During the late Miocene and Pliocene, the sloth genus ''Thalassocnus'' of the west coast of South America became adapted to a shallow-water marine lifestyle. However, the family placement of ''Thalassocnus'' has been disputed; while long considered a nothrotheriid, one recent analysis moves it to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megalonychidae
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 (which was then still connected to South America). 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 (which led to the main pulse of the Great American Interchange). 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 (about 5 to 2 million years ago) species were already approximately half the size of the huge Late Pleistocene ''Megalonyx jeffersonii'' from the last ice age.J.L. White (1993) It was formerly believed, based on morpholo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Choloepodidae. The only other extant family of the suborder Folivora is the distantly related Bradypodidae. Erected as the family Scelidotheriidae by Ameghino in 1889, the taxon was demoted to a subfamily by Gaudin in 1995. However, recent collagen sequence data indicates the group is less closely related to ''Mylodon'' and ''Lestodon'' than '' Choloepus'' is, and thus it has been elevated back to full family status by Presslee ''et al.'' (2019). Taxonomy Together with Mylodontidae, and the two-toed sloths, the scelidotheriids form the superfamily Mylodontoidea. ''Chubutherium'' is an ancestral and very plesiomorph In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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