Species delimitation and phylogenomics of economically important African Pterocarpus trees

Reliable species delimitation is fundamental for establishing clear and equitable guidelines on the sustainable harvest of economically important organisms. Pterocarpus (Fabaceae) is a pantropical tree genus including several highly valuable timber-producing species, that face significant threats from intensive logging. However, a lack of taxonomic clarity has hindered the advance of logging regulations and has led to the inclusion of all African Pterocarpus populations under CITES regulations (CoP19). In our study, we addressed this issue by reassessing species delimitation of African Pterocarpus using a phylogenetic approach. We aimed to assess whether currently accepted species, identified based on morphological characters appear monophyletic, thereby supporting their species status. Our second goal was to evaluate the potential of high-copy genetic material to provide markers for species identification, useful in enforcement of illegal logging and especially important for the five highly logged rosewood species (P. angolensis, P. erinaceus, P. lucens, P. soyauxii and P. tinctorius). We aimed to achieve this by comparing species delimitation between phylogenetic trees obtained via cpDNA and rDNA to that obtained from the low-copy nuclear genes (Angiosperms353).可靠的物种界定（species delimitation）是为具有经济重要性的生物制定清晰且公平的可持续收获管理准则的核心前提。紫檀属（Pterocarpus，豆科Fabaceae）为泛热带分布的木本植物属，包含多种极具经济价值的用材树种，当前正遭受高强度采伐的严重威胁。然而，分类学界定的模糊性阻碍了采伐监管政策的推进，使得所有非洲紫檀属种群均被纳入《濒危野生动植物种国际贸易公约》（CITES）第19届缔约方大会（CoP19）的管制范围。本研究通过系统发育分析方法重新评估非洲紫檀属的物种界定问题，以期解决上述分类学困境。本研究的首要目标为验证基于形态特征确立的现有公认物种是否为单系类群（monophyletic group），以此佐证其物种分类地位的合理性。本研究的第二项目标为评估高拷贝遗传物质作为物种鉴定分子标记的应用潜力，这类标记可用于非法采伐行为的执法监管，对受高强度采伐威胁的5种珍贵红木树种（安哥拉紫檀P. angolensis、刺猬紫檀P. erinaceus、光亮紫檀P. lucens、索氏紫檀P. soyauxii以及染料紫檀P. tinctorius）尤为关键。为实现上述研究目标，本研究将对比基于叶绿体DNA（chloroplast DNA, cpDNA）、核糖体DNA（ribosomal DNA, rDNA）构建的系统发育树，与基于低拷贝核基因（被子植物353基因套件Angiosperms353）所构建的系统发育树的物种界定结果，以验证相关研究假设。