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Pampatheriidae ("Pampas beasts") is an extinct family of large plantigrade armored xenarthrans related to Glyptodontidae, an extinct family of much larger and more heavily armored xenarthrans, as well as to smaller extant armadillos (Dasypodidae). However, Pampatheriidae has existed as a separate lineage at least since the middle Eocene Mustersan age, . Pampatheres evolved in South America during its long period of Cenozoic isolation. Although widespread, they were less diverse and abundant than the armadillos.〔 ''Holmesina'' spread to North America after the formation of the Isthmus of Panama as part of the Great American Interchange. They finally disappeared on both continents in the end-Pleistocene extinctions, about 12,000 years ago. Pampatheres are believed to have attained a weight of up to . Like three-banded armadillos, and unlike glyptodonts, their armored shell was given some flexibility by three movable lateral bands of scutes.〔 The osteoderms (bony plates in the skin comprising the armor) of pampatheres were each covered by a single keratinized scute, unlike osteoderms of armadillos, which have more than one scute.〔 A study of pampathere jaw biomechanics showed that their masticatory musculature was more powerful and more adapted for transverse movements than that of armadillos, leading to the conclusion that much of their diet was coarse vegetation. They are thought to have been primarily grazers, unlike armadillos, which are omnivorous or insectivorous.〔 The variation between species in the expression of adaptations for grinding coarse vegetation correlates with the aridity of their habitat; such adaptations are most pronounced in ''Pampatherium typum'', which lived in the arid Pampas, and least pronounced in ''H. occidentalis'', which lived in humid lowlands. == References == *(Paleodatabase ) *Encyclopedia of the Prehistoric World, By Douglas Palmer 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pampatheriidae」の詳細全文を読む スポンサード リンク
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