Data from: Ecogeographical patterns of morphological variation in pygmy shrews Sorex minutus (Soricomorpha: Soricinae) within a phylogeographic and continental-and-island framework

Ecogeographical patterns of morphological variation were studied in the Eurasian pygmy shrew Sorex minutus aiming to understand the species’ morphological diversity in a continental and island setting, and within the context of previous detailed phylogeographical studies. In total, 568 mandibles and 377 skulls of S. minutus from continental and island populations from Europe and Atlantic islands were examined using a geometric morphometrics approach, and the general relationships of mandible and skull size and shape with geographical and environmental variables were studied. Samples were then pooled into predefined geographical groups to evaluate the morphological differences among them using analyses of variance, aiming to contrast the morphological and genetic relationships based on morphological and genetic distances and ancestral state reconstructions, as well as assess the correlations of morphological, genetic, and geographical distances with Mantel tests. We found significant relationships of mandible size with geographical and environmental variables, fitting the converse Bergmann's rule; however, for skull size, this was less evident. Continental groups of S. minutus could not readily be differentiated from each other by shape. Most island groups of S. minutus were easily discriminated from the continental groups by being larger, indicative of an island effect. Moreover, morphological and genetic distances differed substantially and, again, island groups were distinctive morphologically. Morphological and geographical distances were significantly correlated, although this was not the case for morphological and genetic distances, indicating that morphological variation does not reflect genetic subdivision in S. minutus. Our analyses showed that environmental variables and insularity had important effects on the morphological differentiation of S. minutus.本研究以欧亚小鼩鼱（Eurasian pygmy shrew，Sorex minutus）为研究对象，旨在结合已有详细系统地理学（phylogeographical）研究背景，解析该物种在大陆与岛屿生境中的形态多样性，并探究其形态变异的生态地理格局。研究共采集并检测了采自欧洲大陆、大西洋岛屿的大陆种群与岛屿种群的小鼩鼱样本，包括568件下颌骨与377件颅骨，采用几何形态测量学（geometric morphometrics）方法开展分析，同时探究了下颌骨与颅骨的大小、形状与地理及环境变量间的总体关联。随后将样本按预设地理群组进行合并，通过方差分析（analysis of variance）评估群组间的形态差异；同时基于形态与遗传距离及祖先状态重建（ancestral state reconstructions）对比形态与遗传的关联关系，并借助曼特尔检验（Mantel tests）分析形态、遗传与地理距离间的相关性。研究结果显示，下颌骨大小与地理及环境变量存在显著关联，符合反向伯格曼法则（converse Bergmann's rule）；但颅骨大小的相关规律则相对不显著。大陆种群的小鼩鼱无法通过形态特征有效区分彼此；而多数岛屿种群的小鼩鼱因体型更大，可与大陆种群清晰区分，这一结果印证了岛屿效应（island effect）。此外，形态距离与遗传距离存在显著差异，且岛屿种群同样在形态上具有独特性。形态距离与地理距离呈显著相关，但形态距离与遗传距离并无此类关联，这表明小鼩鼱的形态变异无法反映其遗传分化。本研究分析表明，环境变量与岛屿性（insularity）对小鼩鼱的形态分化具有重要影响。