豆科云实亚科紫荆族和近缘类群的化石研究及其生物地理学意义

The Leguminosae is one of the largest plant groups in the symbiotic-nitrogen-fixation clade on the Tree of Life, which is a cosmopolitan family with global ecological and economic values. Recent molecular systematic studies have suggested that the tribe Cercideae within the subfamily Caesalpinioideae is resolved as the sister group to the remaining legumes, so the fossil records of this tribe and its allies (Detarieae, Cassieae, Caesalpinieae) are pivotal to deeply understand the origin, early diversification, and biogeography of the Leguminosae. However, there has not been a scientific consensus on the biogeographic origin of legumes, because a detailed taxonomic study on the fossil record of tribes Cercideae, Detarieae, Cassieae, and Caesalpinieae is lacking. Based upon the fossil of Bauhinia in Cercideae, we put forward that the tropical zones along the eastern Tethy Seaway may be responsible for the origin and early diversification of legumes, but this hypothesis still needs more robust dataset from palaeobotany and molecular phylogeny. On the basis of the leaf architecture analysis and fruit comparative morphology, the present project will conduct an integrative taxonomic study on the Cercideae and its allies from the Cenozoic of South China, South Asia, and Europe, and further discuss their biogeographic implications.

豆科是生命之树共生固氮支系中最大的植物类群之一，全球分布，具有广泛的生态和经济价值。近来的分子系统学研究表明，云实亚科紫荆族是豆科其余类群的姐妹群，因此它和近缘类群的化石记录对深入认识豆科的起源、早起分化和生物地理至关重要。然而，由于过去对紫荆族及其近缘类群（甘豆族、决明族和云实族）的化石缺乏全面详细的分类梳理，所以有关豆科的生物地理起源问题并未达成一致意见。申请者近来基于紫荆族羊蹄甲属化石，提出东特提斯海道附近的热带地区最有可能关系着豆科植物的起源和早期分化，但这个假说还需要更有力的系统发育关系和化石证据支持。本申请项目拟基于叶结构分析和果比较形态学，对华南、南亚和欧洲紫荆族及近缘类群新生代的化石做一个综合性的分类学研究，并且讨论它们的生物地理学含义。

云实亚科紫荆族是豆科其余类群的姐妹群，因此它和近缘类群的化石记录对深入认识豆科的起源、早起分化和生物地理至关重要。然而，由于过去对紫荆族及其近缘类群（甘豆族、决明族和云实族）的化石缺乏全面详细的分类梳理，所以有关豆科的生物地理起源问题并未达成一致意见。本项目一方面基于叶结构分析和果比较形态学，对华南、南亚和欧洲紫荆族及近缘类群新生代的化石做一个综合性的分类学研究，并且讨论它们的生物地理学含义，另外一方面利用叶绿体基因组数据，重建了紫荆族核心类群羊蹄甲属的系统发育关系，为深入的生物地理学研究奠定基础。