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MYLODON (Gr. for " mill-tooth " from ...

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Originally appearing in Volume V19, Page 113 of the 1911 Encyclopedia Britannica.
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MYLODON (Gr. for " See also:mill-tooth " from /See also:Ark in, and Mobs)  , a genus of See also:extinct See also:American edentate mammals, typified by a See also:species (M. harlani) from the See also:Pleistocene of See also:Kentucky and other parts of the See also:United States, but more abundantly represented in the corresponding formations of See also:South See also:America, especially See also:Argentina and See also:Brazil . The mylodons belong to the See also:group of ground-sloths, and are generally included in the See also:family Megatheriidae, although sometimes made the type of a See also:separate family . From Megatherium these animals, which rivalled the Indianrhinoceros in bulk, differ in the shape of their cheek-See also:teeth; these (five above and four below) being much smaller, with an ovate See also:section, and a cupped instead of a ridged See also:crown-See also:surface, thus resembling those of the true sloths . In certain species of See also:mylodon the front pair of teeth in each See also:jaw is placed some distance in front of the See also:rest and has the crown surface obliquely bevelled by, From See also:Owen . See also:Skeleton of Mylodon robustus (Pleistocene, South America) . wearing against the corresponding teeth in the opposite jaw . On this See also:account such species have been referred to a second genus, under the name of Lestodon, but the distinction scarcely seems necessary . The See also:skull is shorter and See also:lower than in Megatherium, without any See also:vertical expansion of the See also:middle of the lower jaw, and the teeth also extend nearly to the front of the jaws; both these features being See also:sloth-like . In the fore feet the three inner toes have large claws, while the two See also:outer ones are rudimentary and clawless; in the See also:hind-limbs the first toe is wanting, as in Megatherium, but the second and third are clawed . The skin was strengthened by a number of small deeply-embedded bony nodules . Although the typical M. harlani is See also:North—American, the mylodons are essentially a South American group, a few of the representatives of which effected an entrance into North America when that See also:continent became finally connected with South America . See also:Special See also:interest attaches to the See also:recent See also:discovery in the cavern of Ultima Esperanza, South See also:Patagonia, of remains of the genus Glossotherium, or Grypotherium, a near relative of Mylodon, but differing from it in having a bony See also:arch connecting the nasal bones of the skull with the premaxillae; these include a considerable portion of the skin with the See also:hair attached .

Ossicles somewhat resembling large See also:

coffee-berries had been previously found in association with the bones of Mylodon, and in Glossotherium nearly similar ossicles occur embedded on the inner See also:side of the thick hide . The coarse and shaggy hair is somewhat like that of the sloths . The remains, which include not only the skeleton and skin, but likewise the droppings, were found buried in grass which appears to have been chopped up by See also:man, and it thus seems not only evident that these ground-sloths dwelt in the See also:cave, but that there is a considerable See also:probability of their having been kept there in a semi-domesticated See also:state by the See also:early human inhabitants of Patagonia . The extremely fresh See also:condition of the remains has given rise to the See also:idea that Glossotherium may still be living in the wilds of Patagonia . Scelidotherium is another genus of large South American Pleistocene ground-sloths, characterized, among other features, by the See also:elongation and slenderness of the skull, which thus makes a decided approximation to the See also:anteater type, although retaining the full See also:series of cheek-teeth, which were, of course, essential to an herbivorous See also:animal . The feet resemble those of Megatherium . A much smaller South American species represents the genus Nothrotherium . In North America Mylodon was accompanied by another gigantic species typifying the genus Megalonyx, in which the fore See also:part of the skull was usually wide, and the third and See also:fourth front toes carried claws . Another genus has been described from the Pleistocene of See also:Nebraska, as Paramylodon; it has only four pairs of teeth, and an elongate skull with an inflated muzzle . All the above genera differ from Megatherium in having a foramen on the inner side of the lower end of the humerus . A presumed large ground-sloth from See also:Madagascar has been described, on the See also:evidence of a See also:limb-See also:bone, as Bradytherium, but it is suggested by Dr F . Ameghino that the specimen really belongs to a lemuroid .

Be this as it may, the North American mammals described as See also:

Moro pus and Morotherium, in the belief that they were ground-sloths, are really referable to the ungulate group Ancvlopoda . Although a few of the Pleistocene ground-sloths, such as Nothropus and Nothrotherium (= Coelodon), were of comparatively small See also:size, in the See also:Santa Cruz beds of Patagonia few of the representatives of the family much exceeded a See also:modern sloth in size . The best-known generic types are Eucholoeops, Hapalops and Pseudahapalops, of which considerable portions of the skeleton have been disinterred . In these diminutive ground-sloths the crowns of the cheek-teeth approached the prismatic See also:form characteristic of Mega[lo]therium, as distinct from the subcylindrical type occurring in Mylodon, Glossotherium, &c . By many palaeontologists a group of North American Lower See also:Tertiary mammals, known as See also:Ganodonta, has been regarded as representing the ancestral stock of the ground-sloths and those of other South American edentates; but according to See also:Professor W . B . See also:Scott this view is incorrect and there is no See also:affinity between the two See also:groups . If this be so, we are still in See also:complete darkness as to the stock from which the South American edentates are derived . See W . B . Scott, See also:Mammalia of the Santa Cruz Beds, See also:Edentata, See also:Rep., See also:Princeton Exped. to Patagonia, vol. v . (1903—1904); B .

See also:

Brown A New Genus of Ground-Sloth from the Pleistocene of Nebraska, See also:Bull . Amer . See also:Mus . Nat . Hist., xix, 569 (1903) . (R .

End of Article: MYLODON (Gr. for " mill-tooth " from /Ark in, and Mobs)
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