The upper dentition of Crocidura exhibits polymorphic characters that were revealed for the first time in this study via high-resolution X-ray computed microtomography. Our analyses of 11 Crocidura species and selected Diplomesodon, Suncus and Sylvisorex species from different geographical regions and size groups revealed the most complex character states of upper dentition in the Ethiopian endemic species Crocidura yaldeni. A three-dimensionally based geometric morphometric analysis revealed the dependence of variation in skull muzzle shape on alterations in general upper dentition, such as a reduction in the number of antemolars. Principal components analysis revealed highly significant shape alterations and morphological trajectories in C. yaldeni (and more moderate ones in Suncus murinus) toward the Sorex-like morphotype in the outgroup, and less significant shape alterations in Crocidura obscurior, Crocidura phanluongi and Crocidura sapaensis with double-rooted third antemolar. Cladistic analysis based on a new data matrix for 20 species and 46 characters allowed us to determine the directions of the morphological trajectories: the apomorphic state of the most complex antemolars of C. yaldeni is associated with deviating skull muzzle shape changes, which we determined to be attributable to neomorphosis, and the less significant alterations in the shape of other Crocidura with complex antemolars are attributable to regional adaptation.

中文翻译：

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Crocidura（Soricomorpha：Soricidae）的牙齿多态性和crocidurine shew牙列的进化多样化

Crocidura 的上牙列表现出多态性特征，这是本研究通过高分辨率 X 射线计算机显微断层扫描首次揭示的。我们对来自不同地理区域和大小组的 11 种 Crocidura 物种和选定的 Diplomesodon、Suncus 和 Sylvisorex 物种的分析揭示了埃塞俄比亚特有物种 Crocidura yaldeni 中上齿列最复杂的特征状态。基于三维的几何形态测量分析揭示了颅口形状的变化对一般上牙列变化的依赖性，例如前臼齿数量的减少。主成分分析揭示了 C. yaldeni（以及 Suncus murinus 中更温和的）在外群中向 Sorex 样形态型的高度显着的形状改变和形态轨迹，并且具有双根第三前臼齿的 Crocidura obscurior、Crocidura phanluongi 和 Crocidura sapaensis 的形状变化不太显着。基于 20 个物种和 46 个字符的新数据矩阵的分支分析使我们能够确定形态轨迹的方向：C. yaldeni 最复杂的前臼齿的变形状态与头骨口部形状的变化有关，我们确定可归因于新形态，而其他具有复杂前臼齿的Crocidura形状的不太显着变化可归因于区域适应。