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''Macrauchenia'' ("long llama", based on the now superseded Latin term for llamas, ''Auchenia'', from Greek terms which literally mean "big neck") was a long-necked and long-limbed, three-toed South American ungulate mammal, typifying the order Litopterna. The oldest fossils date back to around 7 million years ago, and ''M. patachonica'' disappears from the fossil record during the late Pleistocene, around 20,000-10,000 years ago. ''M. patachonica'' was the best known member of the family Macraucheniidae, and is known only from fossil finds in South America, primarily from the Lujan Formation in Argentina. The original specimen was discovered by Charles Darwin during the voyage of the ''Beagle''. In life, ''Macrauchenia'' resembled a humpless camel with a short trunk, though it is not closely related to either camels or proboscideans.〔(【引用サイトリンク】title=BBC - Science & Nature - Wildfacts - Macrauchenia )〕 ==Description== ''Macrauchenia'' had a somewhat camel-like body, with sturdy legs, a long neck and a relatively small head. Its feet, however, more closely resembled those of a modern rhinoceros, and had three hoofs each. It was a relatively large animal, with a body length of around and a weight up to 1043 kg.〔〔http://sedici.unlp.edu.ar/handle/10915/16838?show=full (in spanish) 〕 One striking characteristic of ''Macrauchenia'' is that, unlike most other mammals, the openings for nostrils on its skull were atop the head, leading some early scientists to believe that, much like a whale, it used these nostrils as a form of snorkel. Soon after some more recent findings, this theory was rejected. An alternative theory is that the animal possessed a trunk, perhaps to keep dust out of the nostrils. ''Macrauchenias trunk may be comparable to that of the modern Saiga antelope. One insight into ''Macrauchenias habits is that its ankle joints and shin bones may indicate that it was adapted to have unusually good mobility, being able to rapidly change direction when it ran at high speed.〔 ''Macrauchenia'' is known, like its relative, ''Theosodon'', to have had a full set of 44 teeth. 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「Macrauchenia」の詳細全文を読む スポンサード リンク
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