啄木鸟科内谱系生物地理学新探

啄木鸟群体共包含254种，但早期对啄木鸟的分类学研究局限于形态学、行为学和鸣唱法等方向，分子研究结果又彼此存在差异，因此啄木鸟分类系统目前还有争议。分子数据的大量累积为啄木鸟系统发育的研究提供了条件。利用从GenBank获取的ND2基因序列，对啄木鸟科179种啄木鸟采用NJ法、MP法以及ML法分别进行了分子进化树构建，同时用NJ法重建了Picumnus属分子进化树。此外又利用cytb基因序列采用NJ法对Dryobates属和Picoides属进行分子进化树重建。我们的结果显示，姬啄木亚科Picumnus属新大陆物种彼此的进化关系仍需进一步研究，而该属唯一一种旧大陆种P.innominatus，种内遗传差异在种间水平依然显著，这说明其种内遗传差异一直被低估了。在啄木鸟亚科内，Hemicircus属和Nesoctites属为姐妹关系，而Geocolaptes olivaceus插入了Campethera属支系中，并非与其构成姐妹群体。此外，一些姐妹群在新旧大陆上的分布，推测这种分布可能与第四纪冰川有关。啄木鸟从旧大陆向新大陆迁移，在第四纪冰川作用下不断发生分布范围的扩张与收缩，最终形成现存的分布格局。

New knowledge about phylogeography of woodpecker (Picidae)

Woodpeckers were used as specific indicators of forest avian diversity because their existence was positively correlated with the richness of other forest birds. Further, woodpeckers primarily excavate cavities in trees for their nesting and then donate for secondary cavity-nester. Additionally, they are indicators of forest conditions because they are highly susceptible to the habitat changes. Thus, woodpeckers play essential roles in forestry ecosystem. Currently, 254 species are recognized as woodpeckers (Picidae) which have further been classified 33 genera. On the one hand, some misconception existed in the previous studies which were associated with mimicry, convergent evolution, and parallel evolution. On the other hand, molecular phylogenetic studies have generally focused on some specific clades. The taxonomy system of woodpeckers is controversial now. It is not easy to study woodpecker family because of their significant species number and the vast distribution ranges, though the aggregation of DNA sequence data in public repositories make things easier. We hope to achieve a molecular phylogenetic study of woodpeckers using these data. We downloaded ND2 gene sequence data of 179 out of the 254 recognized species of woodpeckers and the cytb gene sequence data of Dryobates and Picoides genus from GenBank. Using ND2 gene sequence data, we constructed the phylogenetic trees of 179 species of woodpeckers through Neighbour-Joining (NJ), Maximum-Parsimony (MP), and maximum-likelihood (ML) methods, respectively. Subsequently, we considered Jynx ruficollis as an outgroup and constructed the phylogenetic tree for Picumnus genus using ND2 gene sequence data through the Neighbour-Joining method. Correspondingly, we compared cytb gene sequence data for Dryobates and Picoides genus to reconstruct the trees. We found some differences in our trees which were constructed by different methods. Compared with previous studies, we observed that the ML tree of the 179 woodpeckers was more satisfactory out of three sorts of our constructed phylogenetic trees. Our results support many relationships observed in previous studies and also find some new facts. Initially, our results show a divergence underestimation of P. innominatus which is the only Old World specie in Picumnus genus. We realized that the relationship between other New World species in this genus needed to explore more deeply. Additionally, there are two points need to be highlighted about Picinae. Firstly, there is a need to create a sister relationship between Hemicircus and Nesoctites genus. Secondly, it is required to insert Geocolaptes olivaceus in the clade of Campethera genus. Finally, we observed some sister groups distributed in both New World and Old World. We rebuilt the NJ trees of Picumnus, Dryobates, and Picoides genus as sister groups and each genus consist of both New World and Old World species. Our result implies that these sister groups might be associated with the Pleistocene glacial era. Following glacial cycles of the Pleistocene, there is a circulation of expansion and shrinkage of woodpecker distribution ranges, and it influences the speciation and distributions of Picidae to form modern distribution. Our results revealed an Old World origin of woodpeckers.