Ground sloths Fossil range: Oligocene - Holocene
Harlan's Ground Sloth (Paramylodon harlani), a mylodontid
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Subclass: Theria Infraclass: Eutheria Superorder: Xenarthra Order: Pilosa Suborder: Folivora (partim)
Families
Bradypodidae Megalonychidae †Megatheriidae †Mylodontidae †Orophodontidae †Scelidotheriinae and see text

Ground sloths are a diverse group of extinct sloths, mammals in the edentate superorder Xenarthra. The Oligocene is a geologic epoch of the Paleogene period and extends from about 33 The Holocene is a Geological epoch which began approximately 10000 years ago (about 8000 BC Ground sloths are a diverse group of Extinct Sloths Mammals in the edentate Superorder Xenarthra. Chordates ( Phylum Chordata) are a group of Animals that includes the Vertebrates together with several closely related Invertebrates Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Theria (ˈθɪərɪə from the Greek θηρίον, wild beast is a subclass of Mammals ref> that give birth to live young without See also Evolution of mammals Eutheria ("true beast" are a group of Mammals consisting of Placental mammals plus all extinct Mammals The superorder Xenarthra is a group of Placental mammals (infraclass Eutheria extant today only in the Americas The order Pilosa is a group of placental Mammals extant today only in the Americas The living sloths comprise six Species of medium-sized Mammals that live in Central and South America belonging to the families In Biological classification, family ( Latin The three-toed sloths are the only members of the Bradypus genus and the Bradypodidae family "Megalonychidae" redirects here For the Prehistoric members of this family see Ground sloth#Megalonychidae. Ground sloths are a diverse group of Extinct Sloths Mammals in the edentate Superorder Xenarthra. Ground sloths are a diverse group of Extinct Sloths Mammals in the edentate Superorder Xenarthra. Ground sloths are a diverse group of Extinct Sloths Mammals in the edentate Superorder Xenarthra. The living sloths comprise six Species of medium-sized Mammals that live in Central and South America belonging to the families Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used The superorder Xenarthra is a group of Placental mammals (infraclass Eutheria extant today only in the Americas They may have died out as recently as 1550 in Hispaniola and Cuba (Nowak, 1999), but had long since been extinct on the mainland. Hispaniola (from Spanish, La Española) is the second-largest and most populous Island of the Antilles, lying between the islands of The Republic of Cuba (ˈkjuːbə or) consists of the island of Cuba (the largest and second-most populous island of the Greater Antilles) Isla de la

The bulk of ground sloth evolution took place during the mid to late Tertiary of South America while the continent was isolated. At their earliest appearance in the fossil record, the ground sloths are already distinct at the family level. The formation of the land bridge connecting the American continents in the Miocene allowed a dispersal of forms into North America. A number of mid- to small-sized forms are believed to have dispersed to the Antilles islands either by making short swims or using land bridges that are now submerged. Ground sloths were a hearty group as evidenced by their diverse numbers and dispersals into remote areas given the finding of their remains in southern Patagonia (Last Hope Inlet) and parts of Alaska.

Sloths, and Xenarthrans as a whole, represent one of the more successful South American groups during the Great American Biotic Interchange by establishing a number of taxa in the northern continent. Most taxa moved from North American into South America, with very few going the other way. At least five genera of ground sloth are recognized from North America, and mark the successful colonization of the ground sloths into that continent.

Cryptozoologists often identify the mapinguari, a mythical forest creature of the upper Amazon basin, with a surviving tropical ground sloth or folk memory of these animals. Cryptozoology (from Greek κρυπτός kruptos, "hidden" + Zoology; literally "study of hidden animals" is the study of and search The mapinguari (or mapinguary) ( IPA: /mapiŋgwa'ri/ is a legendary ground-dwelling Sloth -like creature with red Fur living in Folk memories is a term sometimes used to describe stories, Folklore or myths about past events that have passed orally from generation to generation

Families

Paleontologists divide the more than 80 genera of ground sloths in multiple families. Palaeontology redirects here For the Scientific journal, see Palaeontology (journal. A genus (plural genera from Γένος Latin genus "descent family type gender" is a low-level Taxonomic In Biological classification, family ( Latin ^[1] Note that ground sloths do not form a monophyletic group - megalonychid ground sloths are more related to today's living two-toed sloths - than to any other ground sloths. A clade is a taxonomic group comprising a single Common ancestor and all the descendants of that ancestor "Megalonychidae" redirects here For the Prehistoric members of this family see Ground sloth#Megalonychidae. An additional family Rathymotheriidae, containing only the genus Rathymotherium, is sometimes listed. Ground sloths are a diverse group of Extinct Sloths Mammals in the edentate Superorder Xenarthra.

Megalonychidae

The megalonychid ground sloths first appeared in the early Oligocene, about 35 million years ago, in southern Argentina (Patagonia). The Oligocene is a geologic epoch of the Paleogene period and extends from about 33 Llao LLaojpg|thumb|250px| Lake Nahuel Huapi, near Bariloche, Argentina With the rise of the land bridge at Panama, these ground sloths began to migrate north as part of the Great American Interchange. Panama, officially the Republic of Panama (República de Panamá) is the southernmost country of Central America. The Great American Interchange was an important paleozoogeographic event in which land and freshwater fauna migrated from North America via Central Some lineages of megalonychids increased in size as time progressed. 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. The Pliocene epoch (spelled Pleiocene in some older texts is the period in the Geologic timescale that extends The Late Pleistocene (also known as Upper Pleistocene or the Tarantian) is a stage of the Pleistocene Epoch. "Last glacial" redirects here For the period of maximum glacier extent during this time see Last Glacial Maximum The last glacial period Some West Indian island species were as small as a large cat; their dwarf condition typified both tropical adaptation and their restricted island environment. This small size also enabled them a degree of aboreality. ^[2]

Megalonyx, which means "giant claw" is a widespread North American genus, lived past the close of the last (Wisconsin) glaciation, when so many large mammals died out. Ground sloths are a diverse group of Extinct Sloths Mammals in the edentate Superorder Xenarthra. "Last glacial" redirects here For the period of maximum glacier extent during this time see Last Glacial Maximum The last glacial period Remains have been found as far north as Alaska. ^[3] Ongoing excavations at Tarkio Valley in southwest Iowa may reveal something of the familial life of Megalonyx. An adult was found in direct association with two juveniles of different ages, suggesting that adults cared for young of different generations. ^[4]

The earliest known North American megalonychid, Pliometanastes protistus, lived in Florida and the southern U. Florida ( is a state located in the southeastern region of the United States, bordering Alabama to the northwest and Georgia to the S. about 9 million years ago, and is believed to have been the predecessor of Megalonyx. Several species of Megalonyx have been named; in fact it has been stated that "nearly every good specimen has been described as a different species". Ground sloths are a diverse group of Extinct Sloths Mammals in the edentate Superorder Xenarthra. ^[3] A broader perspective on the group, accounting for age, sex, individual and geographic differences, indicates that only three species are valid (M. leptostomus, M. wheatleyi, and M. jeffersonii) in the late Pliocene and Pleistocene of North America. ^[5] Although work by McDonald lists five species. Jefferson's ground sloth has a special place in modern paleontology, for Thomas Jefferson's letter on Megalonyx, read before the American Philosophical Society of Philadelphia, in August 1796, marked the beginning of vertebrate paleontology in North America. Palaeontology redirects here For the Scientific journal, see Palaeontology (journal. Thomas Jefferson (April 13 1743 – July 4 1826 was the third President of the United States (1801–1809 the principal author of the Declaration of Independence The American Philosophical Society is a discussion group founded in 1743 by Benjamin Franklin as an offshoot of his earlier club the Junto. Philadelphia (ˌfɪləˈdɛlfiə Vertebrates are members of the Subphylum Vertebrata, Chordates with backbones or spinal columns The grouping sometimes includes ^[3] When Lewis and Clark set out, Jefferson instructed Meriwether Lewis to keep an eye out for ground sloths. He was hoping they would find some living in the Western range. Megalonyx jeffersonii was appropriately named after Thomas Jefferson. ^[3]

Reconstruction of Megalocnus rodens, which possibly survived to 1500 AD.

The smallish Acratocnus ground sloths disappeared at an unknown date. Acratocnus is an extinct Genus of Ground sloth found in Cuba, Hispaniola and Puerto Rico.

FAMILY MEGALONYCHIDAE Gervais, 1855

Megatheriidae

Fossil Eremotherium skeleton, National Museum of Natural History, Washington, DC. Paul Gervais full name François Louis Paul Gervaise ( September 26, 1816 - February 10, 1879) was a French Palaeontologist Imagocnus is an extinct Genus of ground sloth from the early Miocene of Cuba. Ground sloths are a diverse group of Extinct Sloths Mammals in the edentate Superorder Xenarthra. The Ground sloths of the Genus Megalocnus ("Great Sloth" were among the largest of the Caribbean ground sloths Acratocnus is an extinct Genus of Ground sloth found in Cuba, Hispaniola and Puerto Rico. Synocnus was a Genus of Ground sloth that was about the size of a medium-sized dog and weighed approximately about 50 pounds "Megalonychidae" redirects here For the Prehistoric members of this family see Ground sloth#Megalonychidae. Habanocnus ("Havana sloth" is an extinct Genus of Ground sloth indigenous to Late Pleistocene Cuba. Eremotherium is an extinct genus of Ground sloth. Sources Dinosaur Encyclopedia by Jayne Parsons After The National Museum of Natural History is a Natural history Museum administered by the Smithsonian Institution, located on the National Washington DC ( formally the District of Columbia and commonly referred to as Washington, the District, or simply D

Closeup of hand, showing claws

Closeup of skull

The megatheriid ground sloths are relatives of the megalonychids, with which they form the infraorder Megatheria. This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used Megatheriids appeared later in the Oligocene, some 30 million years ago, also in South America. The group includes the heavily-built Megatherium (given its name 'great beast' by Georges Cuvier^[6]) and Eremotherium. Megatherium ("Great Beast" was a Genus of Elephant -sized Ground sloths that lived from two million to 8000 years ago Baron Georges Léopold Chrétien Frédéric Dagobert Cuvier ( August 23 1769 &ndash May 13, 1832) was a French naturalist Eremotherium is an extinct genus of Ground sloth. Sources Dinosaur Encyclopedia by Jayne Parsons After Other megatheriids, such as the more slightly built nothrotheres Hapalops and Nothrotheriops, reached a length of about 1. Hapalops is an extinct genus of ground sloth from the late Oligocene of South America Nothrotheriops is a genus of Pleistocene Ground sloth found in North and South America. 2 meters.

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 Eremotherium eomigrans from 2. 2 million years ago. With more than five tons in weight, 6 meters in length, and able to reach as high as 17 feet, it was taller than an African Bush Elephant bull. The African Bush Elephant ( Loxodonta africana) is the larger of the two Species of African elephant. Unlike relatives, this species retained a plesiomorphic extra claw. Cladistics is the hierarchical classification of Species based on evolutionary ancestry While other species of Eremotherium had four fingers with only two or three claws, E. eomigrans had five fingers, four of them with claws up to nearly a foot long. ^[7]

The last ground sloths in North America belonging to Nothrotheriops died so recently that their petrified dung (coprolites) has remained undisturbed in some caves, as if it was just recently deposited. A Coprolite is Fossilized animal dung Coprolites are classified as trace fossils as opposed to body fossils as they give evidence for the animal's behaviour (in One of the skeletons, found in a lava tube (cave) at Aden Crater, adjacent to Kilbourne Hole, New Mexico, still had skin and hair preserved, and is now at the Yale Peabody Museum. Lava tubes are natural conduits through which Lava travels beneath the surface of a lava flow expelled by a Volcano during an eruption Kilbourne Hole is a Maar volcanic crater located west of the Franklin mountains of El Paso Texas, in the Potrillo Volcanic Field of Doña Ana County New Mexico ( is a state located in the southwestern region of the United States of America. The American Museum of Natural History in New York City has a sample of dung with a note attached to it that reads "deposited by Theodore Roosevelt". The American Museum of Natural History ( AMNH) located on the Upper West Side, Manhattan, New York, USA is one of the largest and most Theodore Roosevelt (ˈroʊzəvɛlt October 27 1858 January 6 1919 also known as T The largest samples of Nothrotheriops dung can be found in the collections of the Smithsonian Museum. Eventually the Shasta Ground Sloth (Nothrotheriops shastensis) reached the Yukon . Yukon (ˈjuːkɒn is the westernmost and smallest of Canada's three territories.

FAMILY †MEGATHERIIDAE Gray, 1821

Mylodontidae

Another specimen of Paramylodon harlani. Promegatherium ("Before Megatherium " is an Genus of prehistoric Xenarthrans that lived in South America, primarily Megatherium ("Great Beast" was a Genus of Elephant -sized Ground sloths that lived from two million to 8000 years ago Eremotherium is an extinct genus of Ground sloth. Sources Dinosaur Encyclopedia by Jayne Parsons After Nothropus is an extinct genus of Ground sloth. Sources Classification of Mammals by Malcolm C Thalassocnus is an extinct genus of aquatic Sloth from the Miocene and Pliocene of South America. Nothrotherium is an extinct genus of Ground sloth from South America Nothrotheriops is a genus of Pleistocene Ground sloth found in North and South America. Hapalops is an extinct genus of ground sloth from the late Oligocene of South America Texas Memorial Museum, University of Texas at Austin. The Texas Memorial Museum is the main exhibit hall of the Texas Natural Science Center at the University of Texas at Austin in Austin Texas, USA

The mylodontid ground sloths together with their relatives the scelidotheriids and the orophodontids form the Mylodonta, the second radiation of ground sloths. The discovery of their fossils in caverns associated with human occupation lead some early researchers to theorize that the early humans built corrals when they could procure a young ground sloth, to raise the animal to butchering size. ^[8] Subfossil remains like coproliths, fur and skin have been discovered in some quantities. Subfossil refers to remains whose Fossilization process is not complete either for lack of time or because the condition in which they were buried were not optimal for fossilization

There were rumours during the 19th Century from Patagonia that some ground sloths had survived with one explorer noting that a very large hairy beast that looked like a giant armadillo trotted past them and disappeared into the undergrowth during an expedition. The 19th century of the Common Era began on January 1, 1801 and ended on December 31, 1900, according to the Gregorian calendar Llao LLaojpg|thumb|250px| Lake Nahuel Huapi, near Bariloche, Argentina The Giant Armadillo, also variously Tatou, Ocarro, Tatu-canastra or Tatú Carreta, Priodontes maximus is the largest The local Guaraní Indians of the area had preserved lore of ground sloth-like animals that rested during the day in dens dug with their claws and usually only came out at night. Guaraní are a group of culturally related indigenous peoples of South America, distinguished from the related Tupi by their use of the Guaraní language

FAMILY †MYLODONTIDAE Gill, 1872

Scelidotheriidae

Scelidotherium leptocephalum. Incertae sedis ( Latin for "of uncertain placement" abbreviated "inc Glossotherium (literally " Tongue Beast" was a genus of ground Sloth. Paramylodon is an extinct genus of Ground sloth known from North America deposits in Mexico and the United States Mylodon is an Extinct Genus of giant Ground sloth that lived in the Patagonia area of South America until roughly 10000 years ago Scelidotherium is a Genus of South American Pliocene - Pleistocene Ground sloths characterized by an elongated superficially Muséum national d'Histoire naturelle, Paris. The Muséum national d'Histoire naturelle ( MNHN) is the French national Museum of Natural history. Paris (ˈpærɨs in English; in French) is the Capital of France and the country's largest city

Together with the Mylodontidae and the engimatic Pseudoprepotherium, the scelidotheriid ground sloths form the superfamily Mylodontoidea. Taxonomic rank ( rank, category, taxonomic category is an abstract term used in the Scientific classification, or Taxonomy, of organisms Chubutherium is an ancestral and very plesiomorphic member of this family and does not belong to the main group of closely-related genera. Chubutherium ferelloii is an extinct species of Ground sloth (Cattoi 1962 Cladistics is the hierarchical classification of Species based on evolutionary ancestry

FAMILY †SCELIDOTHERIIDAE Ameghino, 1889

• Genus †Chubutherium (basal)
• Subfamily †Scelidotheriinae
  • Genus †Scelidotheriops
  • Genus †Analcitherium
  • Genus †Nematherium
  • Genus †Neonematherium
  • Genus †Elassotherium
  • Genus †Scelidotherium
  • Genus †Catonyx
  • Genus †Proscelidodon

Orophodontidae

The orophodontid ground sloths constitute a rather small but quite distinct group. Chubutherium ferelloii is an extinct species of Ground sloth (Cattoi 1962 In Phylogenetics, a basal Clade is the earliest clade to branch in a larger clade it appears at the base of a cladogram Scelidotherium is a Genus of South American Pliocene - Pleistocene Ground sloths characterized by an elongated superficially They are classified as a distinct mylodontan superfamily Orophodontoidea, the sister taxon to the Mylodontoidea. Taxonomic rank ( rank, category, taxonomic category is an abstract term used in the Scientific classification, or Taxonomy, of organisms Cladistics is the hierarchical classification of Species based on evolutionary ancestry

FAMILY †OROPHODONTIDAE Ameghino, 1895

• Genus †Proplatyarthrus
• Genus †Orophodon
• Genus †Octodontotherium
• Genus †Octomylodon
• Genus †Octodontobradys

Footnotes

In Popular Culture

• Megatherium, a collosal species of ground sloth, is shown in the BBC documentary Walking with Beasts as an omnivore. Walking with Beasts is a 2001 six-part Television documentary produced by the BBC in the United Kingdom, narrated by Kenneth A similar depiction is shown in the Animal Planet Documentary Giant Monsters. Animal Planet is an American Satellite and Cable Television channel (also broadcast via IPTV in the UK) launched on Jeffrey Scott Corwin (born in Norwell Massachusetts) is best known as the host and executive producer of The Jeff Corwin Experience and Corwin's
• Sid the sloth, a major character in the film Ice Age and its sequel, is probably based on the ground sloth, with his bipedal stature. Ice Age is a feature-length computer-animated Film created by Blue Sky Studios and released by 20th Century Fox in 2002 The overall appearance of this sloth is a mixture of characters indicative of Megalonyx and Nothrotheriops.
• The ground sloth makes an appearance in the BBC documentary Prehistoric America, where it is depicted as a herbivore. Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell
• A giant ground sloth appears in the Discovery Channel documentary What killed the Mega Beasts?. Discovery Channel is an American Satellite and Cable TV channel (also delivered via IPTV, Terrestrial television and In the documentary, the ground sloth's extinction was stated to be caused by a combination of over-hunting, rapid climate change, and disease. In Biology and Ecology, extinction is the cessation of existence of a Species or group of taxa. Climate change is any long-term significant change in the “average weather” that a given region experiences

References

• Cuvier, G. (1796): Notice sur le squellette d'une très grande espèce de quadrupède inconnue jusqu'à présent, trouvé au Paraquay, et déposé au cabinet d'histoire naturelle de Madrid. Magasin encyopédique, ou Journal des Sciences, des Lettres et des Arts (1): 303-310; (2): 227-228.
• De Iuliis, G. & Cartelle, C. (1999): A new giant megatheriine ground sloth (Mammalia: Xenarthra: Megatheriidae) from the late Blancan to early Irvingtonian of Florida. Zool. J. Linn. Soc. 127(4): 495-515. Zoological Journal of the Linnean Society is the Scientific journal of the Linnean Society published by Blackwell Publishing Limited.
• Harrington, C. R. (1993): Yukon Beringia Interpretive Center - Jefferson's Ground Sloth. Retrieved 2008-JAN-24.
• Kurtén, Björn and Anderson, Elaine (1980): Pleistocene Mammals of North America. Columbia University Press, New York. ISBN 0-231-03733-3
• McKenna, Malcolm C. & Bell, Susan K. (1997): Classification of Mammals Above the Species Level. Columbia University Press, New York. ISBN 0-231-11013-8
• Nowak, R. M. (1999): Walker's Mammals of the World (Vol. 2). Johns Hopkins University Press, London.
• White, J. L. (1993): Indicators of locomotor habits in Xenarthrans: Evidence for locomotor heterogeneity among fossil sloths. Journal of Vertebrate Paleontology, 13(2): 230-242.
• White, J. L. & MacPhee, R. D. E. (2001): The sloths of the West Indies: a systematic and phylogenetic review. In: Woods, C. A. & Sergile, F. E. (eds. ): Biogeography of the West Indies: Patterns and Perspectives: 201-235.
• 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.
• Picture and information about a ground sloth skeleton on display at the University of Georgia's Science Library.
• Academy of Natural Sciences ground sloth page.
• Illinois State Museum ground sloth page.
• Ground sloths at La Brea.
• Eremotherium in Florida.
• Have some ground sloths survived in Argentina?
• Ground sloths in general.
• Western Center for Archaeology and Paleontology Hemet, CA