Across a variety of taxonomic scales, species diversity is unevenly distributed among its constituent units, and clades with few species are more common than expected assuming homogeneous rates of speciation and extinction among lineages. In order to explain the prevalence of species‐poor families among a global and species‐rich radiation of passerine birds, we test whether these groups share common eco‐morphological, geographical and phylogenetic attributes.

中文翻译：

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外围生态形态预测在有节节的雀形目鸟类中血统多样性和特有性受到限制

在各种分类尺度上，物种多样性在其组成单元之间分布不均，并且假设宗族间物种形成和灭绝的速率相同，物种稀少的进化枝比预期的更为普遍。为了解释雀形目鸟类的全球辐射和物种丰富辐射中物种贫乏科的普遍性，我们测试了这些群体是否具有共同的生态形态，地理和系统发育属性。