Understanding the distribution of Alocasia: Historical biogeography and climate niche separation in sister species pairs

天南星科（Alocasia）共87种，分布于斯里兰卡至亚热带澳大利亚。大多数种是低地林下草本植物，虽然少数生长在暴露的地点或海拔1000米以上。Alocasia在婆罗洲（约40种）、菲律宾（约18种）和新几内亚（约12种）最为多样化。基于化石，Alocasia所属的较大分支起源于始新世的Laurasia，新的分子树和分子定年（使用本提案中报告的数据）建立了Alocasia从北方进入马来地区的假设，并主要从中新世开始多样化，当时温暖潮湿的气候导致了雨林的扩张。我们将用完整的物种抽样来检验这一假设。对于一个物种子集，我们将使用MaxEnt基于砂拉越野外工作的现有/缺失数据和印度尼西亚和马来西亚植物标本馆调查的仅存在数据（已完成试点分析）进行气候生态位建模。物种对生态位的偏好将被放在一个更大的系统发育的背景下，这样就可以推断出变化的方向和时间。这将使我们能够评估气候偏好的变化或保持在Alocasia多样化中的相对作用。我们正在寻求对东南亚分子数据生成、田野调查和植物标本馆访问的支持，这对于完成范围数据和描述新物种是必不可少的。

Alocasia (Araceae) comprises 87 species distributed from Sri Lanka to subtropical Australia. Most species are lowland forest understorey herbs, although a few grow on exposed sites or at elevations above 1000 m. Alocasia is most diverse on Borneo (c. 40 species), the Philippines (c. 18), and New Guinea (c. 12). Based on fossils, the larger clade to which Alocasia belongs originated in Eocene Laurasia, and a new molecular tree and molecular-dating (using data reported in this proposal) set up the hypothesis that Alocasia entered the Malesian region from the North and diversified mainly from the Miocene onwards, when warm-moist climates led to an expansion of rain forests. We will test this hypothesis with complete species sampling. For a subset of species, we will carry out climate niche modeling using MaxEnt based on present/absent data from field work in Sarawak and presence-only data from herbarium surveys in Indonesia and Malaysia (a pilot analysis has been done). Niche preferences of species pairs will be placed in the context of the dated larger phylogeny so that direction and timing of change can be inferred. This will permit assessing the relative roles of changing or conserved climate preferences in the diversification of Alocasia. We are seeking support for molecular data generation, fieldwork, and herbarium visits in Southeast Asia, which are essential for completing range data and for the description of new species.