The Good, the Bad, and the Ugly: The Influence of Skull Reconstructions and Intraspecific Variability in Studies of Cranial Morphometrics in Theropods and Basal Saurischians
The Good, the Bad, and the Ugly: The Influence of Skull Reconstructions and Intraspecific Variability in Studies of Cranial Morphometrics in Theropods and Basal Saurischians
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DOI：
10.1371/journal.pone.0072007
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发表时间：
2013-08-08
期刊：
影响因子：
3.7
通讯作者：
Rauhut, Oliver W. M.
中科院分区：
文献类型：
--
作者：
Foth, Christian;Rauhut, Oliver W. M.
最近发表了几项研究，调查爬行动物化石的宏观进化头骨形状变化，通常使用来自科学文献的头骨重建。然而，这种方法可能存在潜在问题，因为颅骨重建可能会因材料的不完整性和/或变形而显着不同。此外，在这些研究中，种内变异的影响通常没有被探讨。这两个点可以通过影响物种在形态空间内的相对位置来影响形态测量分析的结果。本研究的目的是调查基于同一标本的头骨重建之间的形态测量数据的变化，并比较结果的形状变化发生在头骨重建的基础上不同标本的同一物种（种内变异）和头骨的密切相关的物种（种内变异）。根据目前的结果，基于同一标本的不同颅骨重建的形状变化似乎对几何形态测量分析的结果几乎没有影响，尽管不能排除保存不良标本的一些错误重建偶尔可能会引起问题。与此相反，对于同一物种的不同标本的变化通常高于基于同一标本的不同重建之间的变化。对于密切相关的物种，至少在饮食谱方面具有相似的生态偏好，种间变异的程度可以与种内变异的程度重叠，最可能是由于相似的生物力学约束。
Several studies investigating macroevolutionary skull shape variation in fossil reptiles were published recently, often using skull reconstructions taken from the scientific literature. However, this approach could be potentially problematic, because skull reconstructions might differ notably due to incompleteness and/or deformation of the material. Furthermore, the influence of intraspecific variation has usually not been explored in these studies. Both points could influence the results of morphometric analyses by affecting the relative position of species to each other within the morphospace. The aim of the current study is to investigate the variation in morphometric data between skull reconstructions based on the same specimen, and to compare the results to shape variation occurring in skull reconstructions based on different specimens of the same species (intraspecific variation) and skulls of closely related species (intraspecific variation). Based on the current results, shape variation of different skull reconstructions based on the same specimen seems to have generally little influence on the results of a geometric morphometric analysis, although it cannot be excluded that some erroneous reconstructions of poorly preserved specimens might cause problems occasionally. In contrast, for different specimens of the same species the variation is generally higher than between different reconstructions based on the same specimen. For closely related species, at least with similar ecological preferences in respect to the dietary spectrum, the degree of interspecific variation can overlap with that of intraspecific variation, most probably due to similar biomechanical constraints.