Geographically widespread mitochondrial lineages of the African saw-wings inconsistent with species boundaries

The African saw-wings (genus Psalidoprocne) are a group of swallows endemic to sub-Saharan Africa. Although currently described as five species with several subspecies, the taxonomy of the saw-wings is unclear. We sequenced two mitochondrial genes (ND2 and cytb; 1 717 sites) from 20 individuals in order to investigate phylogenetic relationships across the range of Psalidoprocne. We obtained similar results from maximum likelihood (RAxML) and Bayesian (BEAST) phylogenetic analyses, which reveal multiple well-supported mitochondrial clades in the genus. The geographic overlap of distinct lineages suggests reproductive isolation, although these clades do not correspond entirely to current species designations.

非洲锯翅燕属（Psalidoprocne）是一类为撒哈拉以南非洲特有的燕类。尽管目前该类群被划分为5个物种并包含若干亚种，但其分类学地位仍未明确。本研究对20个个体的2个线粒体基因（ND2与细胞色素b（cytb），共1717个位点）进行测序，以探究锯翅燕属在整个分布范围内的系统发育关系。通过最大似然法（RAxML）与贝叶斯法（BEAST）开展的系统发育分析得到了一致结果，均揭示该属存在多个支持度较高的线粒体演化支系。不同演化支系的地理重叠现象暗示其存在生殖隔离，尽管这些支系与当前的物种界定并不完全吻合。