31-512: Glossotherium is an extinct genus of large mylodontid ground sloths of the subfamily Mylodontinae . It represents one of the best-known members of the family, along with Mylodon and Paramylodon . Reconstructed animals were between 3 and 4 metres (9.8 and 13.1 ft) long and possibly weighed up to 1,002.6–1,500 kg. The majority of finds of Glossotherium date from the Middle and Upper Pleistocene , around 300,000 to 10,000 years ago, with
62-480: A giraffe ) to strip leaves off branches. The Shasta ground sloth is believed to have played an important role in the dispersal of Yucca brevifolia , or Joshua tree, seeds. Preserved dung belonging to the sloth has been found to contain Joshua tree leaves and seeds, confirming that they fed on the trees. It has been suggested that the lack of Shasta ground sloths helping to disperse the seeds to more favourable climates
93-443: A clergyman who then gave it to university staff in 1901. Many fossils were later referred to the two, but N. shastensis wasn't placed in a new genus until 1954 when it was placed in a new genus, Nothrotheriops ("near slothful beast", due to its similarity to Nothrotherium ) by Robert Hoffstetter during a study of fossil sloths. N. texanus was recombined into the genus in 1995, and had many fossils referred to it from Florida,
124-598: A few dating older, as far back Pliocene , about 3.3-3 million years ago. The range included large parts of South America , east of the Andes roughly from latitude 20 to 40 degrees south, leaving out the Amazon Basin in the north. In western South America, finds are also documented north of the equator . The animals largely inhabited the open landscapes of the Pampas and northern savanna regions. Like other mylodonts, Glossotherium
155-409: A foregut fermentation site, Glossotherium could probably survive better on foods of lower nutritional value than other sloths could. Though it is likely Glossotherium primarily ate grasses, it also probably ate a variety of foliage as well and would be better considered a "browser-grazer" than simply a grazer. Evidence from Santa Elina suggests that the niche breadth of G. phoenesis decreased from
186-703: A handful of genera ( Mylodon , Paramylodon and Glossotherium ) and absent in others. The following sloth family phylogenetic tree is based on collagen and mitochondrial DNA sequence data (see Fig. 4 of Presslee et al ., 2019). † Megalocnidae (Caribbean sloths) † Scelidodon sp. † Scelidotherium sp. † Lestodon armatus † Paramylodon harlani † Glossotherium robustus † Mylodon darwinii Choloepus didactylus Choloepus hoffmanni † Megalonychidae Bradypodidae (three-toed sloths) † Nothrotheriidae † Megatheriidae Nothrotheriops shastensis Nothrotheriops
217-510: A new species of Nothrotherium , N. shastensis (species name meaning "from Shasta"). 11 years later in 1916, Smithsonian paleontologist Oliver P. Hay named Nothrotherium texanus (species name meaning "from Texas") based on a partial skull that was transferred from Baylor University in Baylor, Texas. The skull had been collected in the Pleistocene strata of Wheeler County, Texas and given to
248-412: A powerful, muscular tail that it used to form a supporting tripod whenever it shifted from a quadrupedal stance to a bipedal one (i.e. Eremotherium ). Nothrotheriops behaved like all typical ground sloths of North and South America , feeding on various plants like the desert globemallow , cacti , and yucca . It was hunted by various local predators, like dire wolves and Smilodon , from which
279-537: A reduction in tooth number. Sloth teeth also lack the enamel and cuspation pattern generally present in other mammals. Their tooth forms are oval, subrectangular, or elongate irregular ovoid with chisel-shaped "caniniform" teeth anteriorly and "molariform" cheek teeth. Glossotherium has a layer of cementum surrounding all molariform cheek teeth with some traces on caniniform teeth. Cheek teeth in Glossotherium are larger, have more complex shapes, and retain more of
310-556: Is a genus of Pleistocene ground sloth found in North America , from what is now central Mexico to the southern United States. This genus of bear-sized xenarthran was related to the much larger, and far more famous Megatherium , although it has recently been placed in a different family, Nothrotheriidae . The best known species, N. shastensis , is also called the Shasta ground sloth . Nothrotheriops fossils were first collected by
341-421: Is believed to have died out in the Pleistocene (1.8 million to 12,000 years ago). The most recent reported date is about 8,700 years BP. Details of Glossotherium 's diet are unclear since no dung deposits are available for analysis. However, based on dental evidence, Glossotherium was likely more suited to grazing, though it was also probably less efficient at ingesting grasses since its dental apparatus
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#1732858767391372-599: Is causing the trees to suffer. A fossil find had been described from as far north as the Canadian province of Alberta ; however, this report is believed to have been mistaken. The genus lived primarily in the southwestern region of the U.S., from the states of Texas and Oklahoma to California ; it has also been found in Florida . The best known historical specimen was found in a lava tube at Aden Crater in New Mexico ; it
403-492: Is common to fossorial mammals. Glossotherium 's huge nostrils were likely effective for sound emission, with expanded nares possibly related to emission of low frequency sounds up to 600 Hz . Fossils of Glossotherium have been found in: Mylodontidae 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
434-465: 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
465-579: Is on display at the Yale Peabody Museum of Natural History in New Haven, Connecticut . Numerous dung boluses belonging to Nothrotheriops have also been found throughout the southwestern United States and have provided an insight into the diet of these extinct animals. This genus's lineage dates back to the Miocene . The ancestors of Nothrotheriops migrated to North America from South America as part of
496-607: Is overlap in their size ranges, and Glossotherium is generally wider and more robust with a diagnostic increased amount of lateral flare at the predental spout. Glossotherium robustum was endemic to South America and weighed about 1,002.6 to 1,500 kilograms (2,210 to 3,310 lb). Pleistocene records indicate that it was widely distributed between 20°S and 40°S, with a range spanning across Argentina , Brazil , Bolivia , Chile , Colombia , Ecuador , Peru , Uruguay , Venezuela and Paraguay . Sloths have an ever-growing adult dentition . They lack deciduous dentition and have
527-649: The Great American Interchange during the Blancan , about 2.6 MYA. Although N. shastensis was one of the smallest mainland ground sloth species, it still reached 2.75 metres (9.0 ft) from snout to tail tip and weighed 250 kilograms (551 lb) (one-quarter of a tonne) – much smaller than some of its contemporary species such as the Eremotherium , which could easily weigh over two tonnes and be 6 metres (20 ft) long. It had large, stout hindlegs and
558-549: The Pliocene of South America and are represented by the species, G. chapadmalense . All specimens of Pleistocene age are typically lumped into G. robustum and a few other questionable species. Further research is needed at the species level. Due to its size and strength, Glossotherium would have had few natural enemies apart from the South American short-faced bear Arctotherium and sabre-toothed cats such as Smilodon . It
589-579: The University of California's Anthropology Department during an exploration of caves at Potter Creek Cave in Shasta County, California , the fossils dating to the late Quaternary period. These first fossils ( UCMP 8422), consisting of an incomplete mandibular ramus lacking teeth of an individual and 14 additional molars, were sent to the University of California Museum of Paleontology where they were described by paleontologist William Sinclair in 1904 as
620-478: The Last Glacial Maximum onward. Glossotherium had large ear ossicles, similar to those in elephants, which imply the loss of hearing acuity of higher frequencies, further implying an advantage for sensing low frequency sounds, infrasound, or bone-conducting seismic waves. Low frequency sound is useful for long range communication and it is possible that ground sloths used low frequency communication in much
651-540: The cementum layer around all sides of each tooth than the Shasta ground sloth, Nothrotheriops shastensis , and tree sloths. Fossils of this animal have been found in South America . It is closely related to Paramylodon of North America, whose specimens have often been confused with it and assigned to Glossotherium , which in turn was initially assigned to Mylodon . The earliest Glossotherium specimens are known from
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#1732858767391682-579: 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 (three-toed sloths), belongs to a different sloth radiation, Megatherioidea . 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
713-421: The distal humerus and anteriorly broad snouts. Mylodontinae has three famous genera: Mylodon , Paramylodon and Glossotherium . The latter three have frequently been confused for each other in scientific literature, though it is likely Paramylodon and Glossotherium share a more recent common ancestor than with any other mylodontid. Paramylodon is typically larger than Glossotherium , even though there
744-450: The early humans built corrals when they could procure a young ground sloth, to raise the animal to butchering size. However, radiocarbon dates do not support simultaneous occupation of the site by humans and sloths. Subfossil remains like coproliths, fur and skin have been discovered in some quantities. Mylodontids are the only ground sloths confirmed to have osteoderms embedded within their skin, though osteoderms were only present in
775-635: The easternmost occurrence of the genus. Fossils of the best-known species, the Shasta ground sloth ( N. shastensis ), have been found throughout western North America, especially in the American Southwest. It is the ground sloth found in greatest abundance at the La Brea Tar Pits . The most famous specimen was recovered from a lava tube at Aden Crater in New Mexico and was found to still have hair and tendon preserved. This nearly complete specimen
806-489: The largest known burrowing mammal ever. The structure of the auditory system shows that Glossotherium could perceive frequencies in infrasound and probably produce them with the help of its voluminous nasal cavity. The research history of the genus is very complex. The first description was made in 1840 by Richard Owen . However, he discarded the genus name just two years later. Subsequently, this led to persistent confusion and equation with Mylodon and other forms, which
837-559: The same way that it is utilized by elephants. Sloths may have used low frequency sounds for communication in mating calls or other social interactions, or for long-range sound sensing as in predator-prey interactions or weather forecasting. Another possible explanation for hearing in low frequencies may be due to fossorial habits: low hearing frequencies coupled with a short interaural distance suggest that Glossotherium probably had very poor sound localization. This indicates evidence of an underground lifestyle since loss of high frequency hearing
868-454: The sloths may have defended themselves by standing upright on hindlegs and tail and swiping with their long foreclaws, like its distant relative Megatherium , as conjectured in the BBC series Walking with Beasts . The same claws could also have been used as tools to reach past the plant spines and grab softer flowers and fruits. Also, the Shasta ground sloth may have had a prehensile tongue (like
899-532: Was adapted to a more or less grassy diet, as indicated by the broad snout and the design of the teeth. This view is confirmed by isotopic analysis . The anatomical structure of their locomotor system suggests quadrupedal locomotion, but they were also capable of changing to a bipedal stance. The particularly strong construction of the forelimbs is remarkable, leading to the assumption that Glossotherium burrowed underground. Large fossil burrows with corresponding scratch marks support this assumption, possibly making it
930-451: Was more suited to shearing, which would have been too ineffective at processing plant materials down to an ingestible size to obtain adequate nutritive value. More recent tree sloths have a very slow rate of passage of food through the gut and it is likely that Glossotherium did as well. With a likely low metabolic rate, a large body size, a consequently reduced energy requirement for its weight, and an extraordinarily large gut that likely had
961-599: Was not resolved until the 1920s. Especially during the 20th century, Glossotherium was considered identical to the North American Paramylodon . It was not until the 1990s that it became widely accepted that the two genera are independent. Glossotherium belongs to the Mylodontidae , in which it is further subcategorized into the Mylodontinae , characterized both by the loss of the entepicondylar foramen of