Reassessment of the Cranial Characters of Glossotherium and Paramylodon (Mammalia: Xenarthra: Mylodontidae)
Reassessment of the Cranial Characters of Glossotherium and Paramylodon (Mammalia: Xenarthra: Mylodontidae)
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舌兽和副淀粉齿兽颅骨特征的重新评估（哺乳动物：Xenarthra：Mylodontidae）
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发表时间：
2009
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通讯作者：
R. Mcafee
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作者：
R. Mcafee
在Mylodontinae的几个属中存在着命名上的混淆，并导致了北美的Paramylodon与南美洲的Glossotherium同义的假设。对舌兽属和副淀粉齿兽属头盖骨的分类学修订支持它们作为不同属的分离，并提供了一个缺乏的诊断特征列表。使用主成分分析的颅骨和下颌骨测量套件，比率和测量分布的评价，并通过检查定性特征进行评估。结果表明，最大的表征头骨来自有关的颅长与宽度的差异，而下颌骨主要是区分的前牙喷口的定性特征。对产于南美洲的上新世种舌兽（Glossotherium chapadmalense）的研究显示，它们具有指示每个属的特征，但与舌兽（Glossotherium）相比表现得更多，并暂时保留在该属下。混合性状表明G. chapadmalense可能是Paramylodon的祖先，尽管何时何地发生的转变仍然不清楚。在进化过渡期间，Paramylodon crania强调腭长度的增加，而Glossotherium强调颅宽度的增加。© 2009 The Linnean Society of伦敦，Linnean Society Zoological Journal of the Linnean Society，2009，155，885-903。
Nomenclatural confusion has existed within the Mylodontinae for several genera, and has resulted in the supposition that Paramylodon of North America is synonymous with Glossotherium of South America. A taxonomic revision of crania for Glossotherium and Paramylodon upholds their separation as distinct genera and provides a list of diagnostic characters that have been lacking. Assessment was made using principal components analysis for suites of cranial and mandibular measurements, evaluation of ratios and measurement distribution, and by examining qualitative characters. Results show the greatest characterization for the skull comes from differences relating to cranial length versus width, whereas the mandible is predominantly distinguished by qualitative characters of the predental spout. Examination of the Pliocene species Glossotherium chapadmalense from South America shows a combination of characters indicative of each genus, but exhibits more with Glossotherium and is tentatively retained under that genus. The mix of characters indicates that G. chapadmalense is the likely ancestor to Paramylodon, although when and where the transition took place is still unclear. During the evolutionary transition, Paramylodon crania emphasized an increase in length of the palate, whereas those of Glossotherium emphasized an increase in cranial width. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155, 885–903.