Cranial shape transformation in the evolution of the giant panda (Ailuropoda melanoleuca)
Cranial shape transformation in the evolution of the giant panda (Ailuropoda melanoleuca)
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大熊猫（Ailuropoda melanoleuca）进化中的颅骨形状转变
DOI：
10.1007/s00114-010-0748-x
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发表时间：
2011-02-01
影响因子：
--
通讯作者：
Dong, Wei
中科院分区：
文献类型：
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作者：
Figueirido, Borja;Palmqvist, Paul;Dong, Wei
在这项研究中，基于地标的几何形态计量学方法被用于研究大熊猫（Ailuropoda melanoleuca）在进化过程中颅形转变的主要方面。具体来说，我们探讨了现存熊猫对竹子的高度衍生的颅骨适应性是否在熊猫谱系的早期就发展起来了。结果表明，已知最古老的大熊猫“侏儒”小熊猫和晚更新世的大Ailuropoda baconida的整体颅骨形态与它们最近的近亲A。黑色素瘤，这与之前基于定性标准的建议一致。然而，我们也描述了a。microta,。baconi,安达。黑素瘤，包括枕后突的发育、枕区定向和脑壳的扩张。结果，a。与大熊猫相比，微斑虎的形态不太专门化，以纤维和硬食性为食。这些结果通过对熊的上齿尺寸的比较分析得到了证实，该分析揭示了两种熊的相对牙齿尺寸的差异。microtaandA。黑色素瘤，很可能是马赛克进化的结果。因此，我们得出结论，像之前认为的那样，在翼足谱系中，头骨形状并没有保持基本一致，而是在超过200万年的时间里经历了一些变化。
In this study, landmark-based methods of geometric morphometrics are used for investigating the main aspects of cranial shape transformation in the evolution of the giant panda,Ailuropoda melanoleuca. Specifically, we explore if the highly derived cranial adaptations for bamboo feeding of the living panda were developed early in the panda's lineage. Results obtained show that the overall cranial morphologies of the oldest known panda, the “pygmy”Ailuropoda microta, and the late PleistoceneAiluropoda baconiare both very similar to that of their closest living relative,A. melanoleuca, which agrees with a previous proposal based on qualitative criteria. However, we also describe several differences between the crania ofA. microta,A. baconi, andA. melanoleuca, including the development of the postorbital process, the orientation of the occipital region, and the expansion of the braincase. As a result, the cranial morphology ofA. microtashows a less specialized morphology toward a fibrous and durophagous diet compared to the giant panda. These results are confirmed by a comparative analysis of the dimensions of the upper teeth in bears, which has revealed differences in relative tooth size betweenA. microtaandA. melanoleuca, most probably as a result of mosaic evolution. Therefore, we conclude that cranial shape did not remain essentially uniform in theAiluropodalineage, as previously thought, but underwent a number of changes during more than 2 Myr.