Ground Sloths Conservation status: Fossil
Fossil Eremotherium ground sloth skeleton at the National Museum of Natural History, Washington, DC
Scientific classification
Kingdom: Animalia Phylum: Chordata Genus: Zunxoeduica Class: Mammalia Order: Xenarthra
Families
Rathymotheriidae Scelidotheriidae Mylodontidae Orophodontidae Megalonychidae Megatheriidae

Ground sloths are extinct edentate (Order Xenarthra) mammals that are believed to be relatives of tree sloths and three-toed sloths. They may have died out as recently as 1550 in Hispaniola and Cuba (Nowak, 1999), but had long since been extinct on the mainland. Image File history File links Download high resolution version (600x800, 276 KB)Fossil ground sloth skeleton at the National Museum of Natural History; digital photo taken by User:Postdlf, 1-8-05 File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this... Categories: Museum stubs | Museums in Washington, DC | Smithsonian Institution | National Mall | Natural history museums ... Aerial photo (looking NW) of the Washington Monument and the White House in Washington, DC. Washington, D.C., officially the District of Columbia (also known as D.C.; Washington; the Nations Capital; the District; and, historically, the Federal City) is the capital city and administrative district of the United... Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms. ... Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria Placozoa Subregnum Bilateria  Acoelomorpha  Orthonectida  Rhombozoa  Myxozoa  Superphylum Deuterostomia     Chordata (vertebrates, etc. ... Typical Classes Subphylum Urochordata - Tunicates Ascidiacea Thaliacea Larvacea Subphylum Cephalochordata - Lancelets Subphylum Myxini - Hagfishes Subphylum Vertebrata - Vertebrates Petromyzontida - Lampreys Placodermi (extinct) Chondrichthyes - Cartilaginous fishes Acanthodii (extinct) Actinopterygii - Ray-finned fishes Actinistia - Coelacanths Dipnoi - Lungfishes Amphibia - Amphibians Reptilia - Reptiles Aves - Birds Mammalia - Mammals Chordates (phylum Chordata) include the vertebrates, together with... Orders Subclass Monotremata Monotremata Subclass Marsupialia Didelphimorphia Paucituberculata Microbiotheria Dasyuromorphia Peramelemorphia Notoryctemorphia Diprotodontia Subclass Placentalia Xenarthra Dermoptera Desmostylia Scandentia Primates Rodentia Lagomorpha Insectivora Chiroptera Pholidota Carnivora Perissodactyla Artiodactyla Cetacea Afrosoricida Macroscelidea Tubulidentata Hyracoidea Proboscidea Sirenia The mammals are the class of vertebrate animals characterized by the presence of mammary glands... Families Myrmecophagidae Megalonychidae Bradypodidae Dasypodidae The order Xenarthra is a group of placental mammals, extant today only in the Americas. ... Families Rathymotheriidae Scelidotheriidae Mylodontidae Orophodontidae Megalonychidae Megatheriidae Ground sloths are extinct edentate (Order Xenarthra) mammals that are believed to be relatives of tree sloths and three-toed sloths. ... Families Megalonychidae Bradypodidae Sloths are medium-sized South American mammals belonging to the families Megalonychidae and Bradypodidae, part of the order Xenarthra. ... Families Rathymotheriidae Scelidotheriidae Mylodontidae Orophodontidae Megalonychidae Megatheriidae Ground sloths are extinct edentate (Order Xenarthra) mammals that are believed to be relatives of tree sloths and three-toed sloths. ... Families Myrmecophagidae Megalonychidae Bradypodidae Dasypodidae The order Xenarthra is a group of placental mammals, extant today only in the Americas. ... Families Megalonychidae Bradypodidae Sloths are medium-sized South American mammals belonging to the families Megalonychidae and Bradypodidae, part of the order Xenarthra. ... Families Megalonychidae Bradypodidae Sloths are medium-sized South American mammals belonging to the families Megalonychidae and Bradypodidae, part of the order Xenarthra. ... Events February 7 - Julius III becomes Pope. ... 15th century map of Hispaniola Hispaniola (from Spanish, La Española) is the second-largest island of the Antilles, lying east of Cuba. ...

The four identified species found in the United States consist of Harlan's Ground Sloth (Paramylodon harlani), Jefferson's Ground Sloth (Megalonyx jeffersonii), Laurillard's Ground Sloth (Eremotherium laurillardi), and the Shasta Ground Sloth (Nothrotheriops shastensis). All four were massive animals with large claws, and all are believed to have been herbivores. Jefferson's and Harlan's Ground Sloths can be found as fossil remnants in the midwestern U.S. In biology, a species is, loosely speaking, a group of related organisms that share a more or less distinctive form and are capable of interbreeding. ... In zoology, an herbivore is an animal that is adapted to eat primarily plant matter (rather than meat). ... A fossil Ammonite Fossils are the mineralized remains of animals or plants or other traces such as footprints. ...

Families

Paleontologists divide the ground sloths in multiple families. Megalonychidae and Megatheriidae are among the most important. A paleontologist carefully chips rock from a column of dinosaur vertebrae. ...

Megalonychidae

The Megalonychid ('giant claw') ground sloths first appeared in the early Oligocene, about 35 million years ago, in southern Argentina (Patagonia). With the rise of the land bridge at Panama, these ground sloths began to migrate north. Eventually the Shasta giant ground sloth (Nothrotheriops shastensis) reached the Yukon. Megalonychids increased in size as time progressed. The first species 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 late Pleistocene Megalonyx jeffersonii. Some West Indian island species were as small as a large cat; their dwarf condition typified both tropical adaptation and their restricted island environment. The Oligocene epoch is a geologic period of time that extends from about 34 million to 23 million years before the present. ... Patagonia is that portion of South America which, to the east of the Andes, lies mainly south of the Rio Negro (41°S), and, to the west of the Andes, south of (42°S). ... Motto: none Other Canadian provinces and territories Capital Whitehorse Largest city Whitehorse Commissioner Jack Cable Premier Dennis Fentie (Yukon Party) Area 482,443 km² (9th)  - Land 474,391 km²  - Water 8,052 km² (1. ... The Pliocene epoch is the period in the geologic timescale that extends from 5. ... The Pleistocene Epoch is part of the geologic timescale, usually dated as 1. ...

The earliest known North American megalonychid, Pliometanastes protistus, lived in Florida about 8 million years ago. 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". 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. World map showing location of North America A satellite composite image of North America North America is a continent in the northern hemisphere, bounded on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the south by the Caribbean Sea, and on the west... State nickname: Sunshine State Other U.S. States Capital Tallahassee Largest city Jacksonville Governor Jeb Bush Official languages English Area 170,451 km² (22nd)  - Land 137,374 km²  - Water 30,486 km² (17. ...

Closeup of skull

Jefferson's ground sloth has a special place in modern paleontology, for Thomas Jefferson's letter on Megalonyx ("great claw"), read before the American Philosophical Society of Philadelphia, in August 1796, marked the beginning of vertebrate paleontology in North America. 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. Image File history File links Skull of fossil ground sloth skeleton at the National Museum of Natural History; digital photo taken by User:Postdlf, 1-8-05 File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Skull of fossil ground sloth skeleton at the National Museum of Natural History; digital photo taken by User:Postdlf, 1-8-05 File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... A paleontologist carefully chips rock from a column of dinosaur vertebrae. ... Order: 3rd President Vice President: Aaron Burr; George Clinton Term of office: March 4, 1801 – March 4, 1809 Preceded by: John Adams Succeeded by: James Madison Date of birth: April 13, 1743 Place of birth: Shadwell, Virginia Date of death: July 4, 1826 Place of death: Charlottesville, Virginia First Lady... The American Philosophical Society, founded in 1743 by Benjamin Franklin, continues to operate to this day. ... Philadelphia is a village located in Jefferson County, New York. ... Typical classes Petromyzontidae (lampreys) Placodermi - extinct Chondrichthyes (cartilaginous fish) Acanthodii - extinct Actinopterygii (ray-finned fish) Actinistia (coelacanths) Dipnoi (lungfish) Amphibia (amphibians) Reptilia (reptiles) Aves (birds) Mammalia (mammals) Vertebrata is a subphylum of chordates, specifically, those with backbones or spinal columns. ... The Lewis and Clark expedition (1804-1806) was the first American overland expedition to the Pacific coast and back. ...

Megalonyx, a widespread North American genus, lived past the close of the last (Wisconsinan) glaciation, when so many large mammals died out. The last ground sloths died so recently that their dung ('coprolites') remains in caves. One of the skeletons, found in a lava tube (cave) at Aden Crater, adjacent to Kilbourne Hole, New Mexico, is now at the American Museum of Natural History. 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". Coprolites are fossilized feces, or animal dung. ... Lava tubes are natural conduits through which lava travels beneath the surface of a lava flow. ... Kilbourne Hole is a Maar volcanic crater, located 30 miles west of the Franklin mountains of El Paso, Texas, in Doña Ana County, New Mexico. ... State nickname: Land of Enchantment Other U.S. States Capital Santa Fe Largest city Albuquerque Governor Bill Richardson Official languages English and Spanish Area 315,194 km² (5th)  - Land 314,590 km²  - Water 607 km² (0. ... The American Museum of Natural History is a landmark of Manhattans Upper West Side in New York, at 79th Street and Central Park West. ... Order: 26th President Vice President: Charles Warren Fairbanks Term of office: September 14, 1901 – March 3, 1909 Preceded by: William McKinley Succeeded by: William Howard Taft Date of birth: October 27, 1858 Place of birth: New York City Date of death: January 6, 1919 Place of death: Oyster Bay, New...

Closeup of hand, showing claws

Image File history File links Hand of fossil ground sloth skeleton at the National Museum of Natural History; digital photo taken by User:Postdlf, 1-8-05 File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Hand of fossil ground sloth skeleton at the National Museum of Natural History; digital photo taken by User:Postdlf, 1-8-05 File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...

Megatheriidae

The Megatheriid ground sloths 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 Richard Owen) and Eremotherium. Eremotherium eomigrans, which has been found in 2.2 million year-old sediments in Florida, reached a length of 6 meters and had the bulk of a bull elephant. Other ground sloths, such Nothrotheres as the slighter built Hapalops and Nothrotheriops line, reached a length of about 1.2 meters, still larger than the living three-toed sloths that are their descendents. Megatheria were a group of elephant-size giant sloths that lived from 2 million to 8,000 years ago. ... Sir Richard Owen and Dinornis bird skeleton Sir Richard Owen (July 20, 1804 - December 18, 1892) was an English biologist, comparative anatomist and palaeontologist. ... Genera and Species Loxodonta Loxodonta cyclotis Loxodonta africana Elephas Elephas maximus Elephas recki (extinct) Stegodon (extinct) Deinotherium (extinct) Mammuthus (extinct) Elephantidae (the elephants) is the only extant family in the order Proboscidea. ...

A forest creature of the upper Amazon basin called the mapinguari may be a surviving tropical ground sloth. The name Amazon may refer to several concepts: The legendary Amazons, women renowned in antiquity for their prowess in battle. ...

La Brea Tar Pits

Two ground sloths are among the animals that were trapped in the La Brea Tar Pits. Harlan's ground sloth (Paramylodon harlani) was six feet tall when it reared up to browse high twigs and leaves. One of the most interesting features of the Harlan's ground sloth were its skin bones, or dermal ossicles. These small bones were deep under the skin around the neck, shoulders and back and may have served as armor against attacking predators. The smaller ground sloth, less common in the La Brea Lagerstätte is the Shasta ground sloth (Nothrotheriops shastensis) La Brea Tar Pits in Los Angeles County, Hancock Park (the animals are models only) The La Brea Tar Pits are tar pits in Hancock Park, Los Angeles, California; here buried asphalt seeps to the surface from the extensive petroleum deposits below the surface of the Los Angeles Basin. ... Lagerstätten (German, singular: Lagerstätte, literally: place(s) of storage or resting place(s)) are sedimentary deposits that exhibit extraordinary fossil richness or completeness. ...

Taxonomy of Ground Sloths

Harlan's ground sloth (Paramylodon harlani), National Museum of Natural History

Modified from McKenna and Bell (1997). "+" indicates an extinct group. Ground sloths consist of 6 families and 88 genera. Note that ground sloths do not form a monophyletic group. Some extinct ground sloths are more related to today's tree sloths than they are to other ground sloths. Image File history File links Paramylodon harlani ground sloth fossil at the National Museum of Natural History, Washington, DC; digital photo taken by User:Postdlf, 2/20/05 File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Paramylodon harlani ground sloth fossil at the National Museum of Natural History, Washington, DC; digital photo taken by User:Postdlf, 2/20/05 File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... In phylogenetics, a group is monophyletic (Greek: of one stem) if all organisms in that group are known to have developed from a common ancestral form, and all descendants of that form are included in the group. ...

• Infraorder Phyllophaga - sloths
  • +Diellipsodon incertae sedis
  • +Amphiocnus incertae sedis
  • +Pseudoglyptodon incertae sedis
  • Family +Rathymotheriidae incertae sedis
    • +Rathymotherium
  • Parvorder +Mylodonta - mylodont ground sloths
    • Superfamily +Mylodontoidea
      • +Pseudoprepotherium incertae sedis
      • Family +Scelidotheriidae
        • Subfamily +Chubutheriinae
          • +Chubutherium
        • Subfamily +Scelidotheriinae
          • +Scelidotheriops
          • +Analcitherium
          • +Nematherium
          • +Neonematherium
          • +Elassotherium
          • +Scelidotherium
      • Family +Mylodontidae
        • +Urumacotherium incertae sedis
        • Subfamily +Mylodontinae
          • +Glossotheriopsis
          • +Promylodon
          • +Strabsodon
          • +Megabradys
          • +Pleurolestodon
          • +Mylodon
        • Subfamily +Lestodontinae
          • Tribe +Thinobadistini
            • +Thinobadistes
            • +Sphenotherus
          • Tribe +Glossotheriini
            • +Acremylodon
            • +Ranculcus
            • +Glossotherium
            • +Paramylodon
            • +Mylodonopsis
          • Tribe +Lestodontini
            • +Lestodon
            • +Lestodontidion
    • Superfamily +Orophodontoidea
      • Family +Orophodontidae
        • +Proplatyarthrus
        • +Orophodon
        • +Octodontotherium
        • +Octomylodon
        • +Octodontobradys
  • Parvorder Megatheria - ground sloths and modern tree sloths
    • Superfamily Megatherioidea
      • Family +Megatheriidae
        • Subfamily +Megatheriinae
          • Tribe +Megatheriini
            • Subtribe +Prepotheriina
              • +Proprepotherium
              • +Planops
              • +Prepotherium
            • Subtribe +Megatheriina
              • +Megathericulus
              • +Promegatherium
              • +Plesiomegatherium
              • +Megatheridium
              • +Pyramiodontherium
              • +Megatherium
              • +Eremotherium
              • +Ocnopus
              • +Perezfontanatherium
          • Tribe +Nothrotheriini
            • +Pronothrotherium
            • +Xyophorus
            • +Chasicobradys
            • +Gilsolaresia
            • +Diheterocnus
            • +Synhapalops
            • +Nothropus
            • +Thalassocnus
            • +Nothrotherium
            • +Nothrotheriops
        • Subfamily +Schismotheriinae
          • +Hapaloides
          • +Schismotherium
          • +Hapalops
          • +Pelecyodon
          • +Parapelecyodon
          • +Analcimorphus
          • +Hyperleptus
          • +Neohapalops
      • Family Megalonychidae - ground sloths and two-toed tree sloths
        • +Imagocnus incertae sedis
        • Subfamily +Ortotheriinae
          • +Proschisomotherium
          • +Eucholoeops
          • +Pseudortotherium
          • +Megalonychotherium
          • +Paranabradys
          • +Pliomorphus
          • +Torcellia
          • +Ortotherium
          • +Menilaus
          • +Diodomus
          • +Habanocnus
          • +Paulocnus
        • Subfamily Megalonychinae
          • +Pliometanastes incertae sedis
          • +Sinclairia incertae sedis
          • +Megalonychops incertae sedis
          • +Valgipes incertae sedis
          • +Meizonyx incertae sedis
          • Tribe +Megalonychini
            • Subtribe +Megalonychina
              • Infratribe +Megalonychi
                • +Protomegalonyx
                • +Megalonyx
              • Infratribe +Megalocni
                • +Megalocnus
                • +Neomesocnus
            • Subtribe +Mesocnina
              • +Neocnus
              • +Parocnus - greater Haitian ground sloth
          • Tribe Choloepodini
            • Subtribe +Acratocnina
              • +Miocnus
              • +Acratocnus
              • +Synocnus - lesser Haitian ground sloth
            • (Subtribe Choloepodina - modern two-toed sloths)
    • (Superfamily Bradypodoidea - modern three-toed sloths)

Families Megalonychidae Bradypodidae Sloths are medium-sized South American mammals belonging to the families Megalonychidae and Bradypodidae, part of the order Xenarthra. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... The Mylodon was a smaller breed of ground sloth, approximately ox-sized, related to the Megatherium and modern three-toed sloths and two-toed sloths. ... Megatheria were a group of elephant-size giant sloths that lived from 2 million to 8,000 years ago. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... Families Megalonychidae Bradypodidae Sloths are medium-sized South American mammals belonging to the families Megalonychidae and Bradypodidae, part of the order Xenarthra. ...

References

• McKenna, M. C, and S. K. Bell. 1997. Classification of Mammals Above the Species Level. Columbia University Press, New York, 631 pp.
• Nowak, R. M. 1999. Walker's Mammals of the World, Vol. 2. Johns Hopkins University Press, London.
• White, J.L. & MacPhee, R.D.E. 2001. The sloths of the West Indies: a systematic and phylogenetic review. pp 201-235 in Woods, C.A. & Sergile, F.E. (eds.). Biogeography of the West Indies: Patterns and Perspectives

External links

• 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.