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，旨在探究该物种在大陆与岛屿生境中的形态多样性，并结合既往详尽的系统地理学（phylogeographical）研究背景，分析其形态变异的生态地理格局。本研究共采集了来自欧洲大陆及大西洋岛屿种群的568件下颌骨（mandible）与377件颅骨（skull）标本，采用几何形态测量学（geometric morphometrics）方法开展分析，探究下颌骨与颅骨的大小、形状与地理及环境变量之间的总体关联。随后将样本按预先定义的地理群组进行合并，通过方差分析评估各组间的形态差异，旨在基于形态距离、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、遗传与地理距离之间的相关性。研究发现，下颌骨大小与地理及环境变量存在显著关联，符合反伯格曼法则（converse Bergmann's rule）；但颅骨大小的相关规律则并不显著。欧亚小鼩鼱的大陆种群间难以通过形态形状进行有效区分，多数岛屿种群因体型更大，可与大陆种群显著区分，这体现了岛屿效应（island effect）。此外，形态距离与遗传距离存在显著差异，且岛屿种群在形态上同样具有独特性。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显著关联，表明欧亚小鼩鼱的形态变异并未反映其遗传分化。本研究结果表明，环境变量与岛屿性（insularity）对欧亚小鼩鼱的形态分化具有重要影响。