Allopatric speciation in Asia contributed to the diversity anomaly between eastern Asia and eastern North America: evidence from anchored phylogenomics of Stewartia (Theaceae)

Premise of the research. The disjunct distribution of plant genera between eastern Asia (EA) and eastern North America (ENA) has long attracted the attention of biologists and biogeographers. For most genera that have been studied, there are more species in EA than ENA and the diversity anomaly may have resulted from the greater physiographical heterogeneity in conjunction with climate and sea level changes in EA than in ENA. However, few empirical studies have explicitly tested the association between species diversity and allopatric speciation events. The genus Stewartia (Theaceae) displays this diversity anomaly with two species in ENA and 21 species in EA, but the phylogeny of this group has not been resolved due to insufficient data.
Methodology. Here, we sampled 15 species of Stewartia (65%) and generated data from over 500 nuclear loci using the anchored phylogenomic approach to produce a robust phylogeny of Stewartia. In addition, biogeographical analyses were performed to el...

研究背景。东亚（EA）与北美东部（ENA）之间植物属的间断分布长期以来一直吸引着生物学家和生物地理学家的关注。对于已研究的大多数属而言，东亚的物种数量多于北美东部，这种多样性异常可能源于东亚较北美东部更为复杂的地貌异质性，以及与之相关的气候和海平面变化。然而，鲜有实证研究明确检验物种多样性与异域物种形成事件之间的关联。Stewartia属（山茶科，Theaceae）呈现出这种多样性异常——北美东部有2种，东亚有21种——但由于数据不足，该类群的系统发育关系尚未得到解析。
研究方法。本研究中，我们采集了Stewartia属15个物种（占总物种数的65%），并通过锚定系统基因组学方法生成了500多个核基因座的数据，以构建该属的稳健系统发育树。此外，我们还进行了生物地理学分析以...