Natural and social selection are among the main shapers of biological diversity but their relative importance in divergence remains understudied. Additionally, although neutral evolutionary processes may promote phenotypic divergence, their potential contribution in speciation is often overlooked in studies of comparative morphology. In this study, we investigated phenotypic differentiation in two allopatric shorebirds: the Palaearctic Common Snipe Gallinago gallinago and the Nearctic Wilson's Snipe Gallinago delicata. Specimens of Common Snipe (n = 355 skins, n = 163 skeletons) and Wilson's Snipe (n = 403 skins, n = 141 skeletons) in natural history collections were examined to quantify differences in skeletal and external measurements, and measures of wing and tail plumage variables. The species do not differ in skeletal variables except for the relatively larger sternum of the Common Snipe. The two species do not differ in multivariate wing size or shape (pointedness). Previously known plumage differences between these species were confirmed: the Common Snipe has fewer rectrices, longer and wider outermost rectrices, more extensive white on tips of the secondary feathers, and more white in the axillaries. Between‐species variance in skeleton, primary length and plumage variables was greater than expected if drift was mainly responsible for phenotypic divergence, suggesting a role of selective processes. However, drift could not be rejected after adjusting for multiple comparisons. Differences in plumage traits were greater than in skeletal or external measurements. Because snipe use plumage traits in signalling, the results suggest a more rapid divergence in socially selected traits between these species than in traits related to resource use.

中文翻译：

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在两个同级的水鸟物种的表型差异中：普通Sn和威尔逊Sn（Charadriiformes ：:科）

自然和社会选择是生物多样性的主要塑造者之一，但它们在多样性中的相对重要性仍未得到研究。此外，尽管中性进化过程可能会促进表型差异，但在比较形态学研究中，它们在物种形成中的潜在作用常常被忽略。在这项研究中，我们调查了两种异源性shore鸟的表型分化：古北常见的ipe子Gallinago gallinago和Nearctic Wilson的Sn子Gallinago delicata。普通狙击（n  = 355皮，n  = 163骷髅）和威尔逊的狙击（n  = 403皮，n 对自然历史记录中的141个骨骼进行了检查，以量化骨骼和外部测量值以及机翼和尾羽全身变量的测量值之间的差异。该物种的骨骼变量没有区别，只是“共同狙击”的胸骨相对较大。这两个种类在机翼大小或形状（指向性）上没有差异。这些物种之间先前已知的羽毛差异得到了确认：“普通ipe”的网眼较少，最外层的网眼更长和更宽，次羽尖上的白色更广泛，而腋下的白色则更多。如果漂移主要是造成表型差异的原因，骨骼之间的物种间差异，初级长度和羽化变量比预期的要大，这表明了选择性过程的作用。然而，在为多个比较进行调整后，不能拒绝漂移。羽毛特征的差异大于骨骼或外部测量的差异。由于狙击在发信号中使用了羽毛特征，因此结果表明，这些物种之间社会选择的特征比与资源利用相关的特征更加迅速地分化。