The first major primate extinction: An evaluation of paleoecological dynamics of North American stem primates using a homology free measure of tooth shape.
The first major primate extinction: An evaluation of paleoecological dynamics of North American stem primates using a homology free measure of tooth shape.
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DOI：
10.1002/ajpa.22927
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发表时间：
2016-04
影响因子：
2.8
通讯作者：
Kristen A. Prufrock;D. Boyer;M. Silcox
中科院分区：
文献类型：
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作者：
Kristen A. Prufrock;D. Boyer;M. Silcox
古新世晚期，北美的类人猿（茎灵长类动物，或类人猿）的消失被归因于与啮齿类动物争夺食物资源。本研究比较了臼齿形态的plesiadapoids和早期啮齿动物，以评估是否所有的类群都适应消费具有类似机械功效的相同结构特性的食物。材料与方法使用Dirichlet正常能量（DNE）对plesiadapoids（n = 181）和ischyromyid（早期化石）啮齿动物（n = 13）的第二下颌磨牙（M2 s）的Micro-CT扫描进行评价，DNE是一种牙齿地形度量，可量化牙齿咬合面的曲率，与咬合面的方向无关;该度量可用于推断饮食。结果：类人猿和啮齿类动物的DNE值的比较表明，啮齿类动物共享功能相似的牙齿形态与至少一些类人猿类人猿类人猿类人猿，因此可能适应于加工具有相似物理特性的食品。然而，啮齿动物的DNE值与其他两个plesiadapoid家庭，Carpolestidae和Saxonellidae的显着对比。结论：与啮齿动物对食物资源的直接竞争不太可能在卡波雷蒂斯和萨索内利斯的灭绝中发挥重要作用，因为这些家庭的成员能够消费啮齿动物无法获得的一系列食物。虽然有几个类人猿与啮齿类动物的DNE值范围重叠，但只有三个在时间上重叠。其中之一（Plesiadapis cookei）可能太大，无法与啮齿动物直接竞争，另一种（Plesiadapis dubius）的DNE值与啮齿动物的DNE值有很大不同（更高），而第三种，Chiromyoides，具有牙齿与克拉克福克啮齿动物的牙齿相似的大小和DNE值。如果饮食生态位重叠与啮齿类动物的下降中发挥了直接作用的plesiadapiforms，它只能有可能这样做的Chiromyoides。
OBJECTIVES The disappearance of the North American plesiadapoids (stem primates, or plesiadapiforms) in the latest Paleocene has been attributed to competition with rodents over dietary resources. This study compares molar morphology of plesiadapoids and early rodents to assess whether all taxa were adapted to consuming foods of the same structural properties with similar mechanical efficacy. MATERIALS AND METHODS Micro-CT scans of second mandibular molars (M2 s) of plesiadapoids (n = 181) and ischyromyid (early fossil) rodents (n = 13) were evaluated using Dirichlet normal energy (DNE), a dental topographic metric that quantifies the curvature of a tooth's occlusal surface, independent of the orientation of the occlusal plane; this metric can be used to infer diet. RESULTS Comparisons of DNE values for plesiadapoids and rodents show that rodents shared functionally similar dental morphology with at least some plesiadapid plesiadapoids and thus were likely adapted to processing foods with similar physical properties. However, the DNE values for rodents contrast markedly with those for the other two plesiadapoid families, the Carpolestidae and Saxonellidae. CONCLUSIONS It is unlikely that direct competition over food resources with rodents played a major role in the extinction of carpolestids and saxonellids, as members of these families were capable of consuming a range of foods that were not accessible to rodents. Although several plesiadapid species overlap with rodents in their range of DNE values, only three overlap in time. One of these (Plesiadapis cookei) may have been too large to be in direct competition with rodents, another (Plesiadapis dubius) has DNE values substantially different (higher) than those of rodents, whereas the third, Chiromyoides, has teeth of both a similar size and DNE value to those of Clarkforkian rodents. If dietary niche overlap with rodents played a direct role in the decline of plesiadapiforms, it can only have potentially done so for Chiromyoides.