Biodiversity, phylogeny and biogeography of African and Madagascan Melastomataceae

泛热带褐花草科（172属，4800-5000种）是被子植物十大科之一。它们可以通过其顶生的叶脉和美丽的花来识别，大部分是孢子状的，雄蕊有明显的装饰。众所周知，非洲的褐藻科成员研究不足，在分子研究中几乎没有代表。Melastomateae是非洲最多样化的部落，有13属约185种，而马达加斯加有9属约70种。对新热带褐藻科的详细分子研究表明，古热带属形成了一个起源于新热带祖先的单系谱系。Dissotis，目前在非洲-马达加斯加岛的最大属（120种），似乎是多种的。尽管非洲-马达加斯加Melastomateae的多样性很高，但迄今为止只有17种被纳入分子系统发育研究。由于缺乏全面的形态学和分子研究，非洲、马达加斯加和亚洲三属间的关系尚不完全清楚，其形态和生物地理进化也不清楚。本研究项目的主要目标是通过对非洲和马达加斯加（以及来自亚洲的精选代表）的120个物种和所有属的160个物种的密集分类群取样，以及对多个快速进化的基因组区域进行测序，并根据植物标本馆标本的研究对谱系进行仔细的形态学和地理调查，来解决非洲-马达加斯加Melastomateae的属间关系。由于进一步的进化研究依赖于对这个很大程度上未知的非洲谱系的深入分类学理解，系统的基础将是我们的首要目标。然后利用分子树重建古热带褐藻科的分化时间、地理和形态多样性。将Cailliella、pseudobeckia、Dionychastrum和Nerophila等古地方病纳入研究，将有助于我们了解Melastomateae在非洲和马达加斯加的起源和传播。对该群体花形态的研究将集中在雄蕊形态和异花异种的进化上，这对传粉综合征有直接（可能是快速）的影响，可能是该群体多样化的一个关键特征。我们的研究结果将对计划中的科植物区系处理产生强烈而直接的影响，例如正在进行的中非区系处理以及喀麦隆和加蓬区系的更新，从而有助于这些地区的植物区系生物多样性调查。

The pantropical Melastomataceae s.l. (172 gen., 4800-5000 spp.) rank among the ten largest angiosperm families. They can be recognized by their acrodromous leaf venation and beautiful flowers with mostly poricidal and conspicuously ornamented stamens. African members of Melastomataceae are notoriously understudied and only scarcely represented in molecular studies. Melastomateae is the most diverse tribe in Africa with ca. 185 species in 13 genera, while Madagascar has about 70 species in nine genera. A detailed molecular study of neotropical Melastomateae showed that the paleotropical genera form a monophyletic lineage originating from neotropical ancestors. Dissotis, currently the largest genus (120 spp.) in the Afro-Madagacan Melastomateae, seems to be polyphyletic. Despite, the high diversity of Afro-Madagascan Melastomateae, only 17 species have so far been included in molecular phylogenetic studies. Due to the lack of a comprehensive morphological and molecular treatment, the relationships among African, Madagascan, and Asian genera of Melastomateae are incompletely resolved and their morphological and biogeographical evolution is poorly understood. The main objective proposed for this research project is to resolve generic relationships in the African-Madagascan Melastomateae based on a dense taxon sampling comprising 160 accessions representing 120 species and all genera in Africa and Madagascar (and selected representatives from Asia) and sequencing of multiple fast-evolving genomic regions complemented by a careful morphological and geographical survey of the lineage based on the study of herbarium specimens. Since further evolutionary studies in Melastomateae depend on a deep taxonomical understanding of this largely unknown African lineage the systematic groundwork will be our first prime goal. Then the molecular trees will be used to reconstruct divergence times, geographical and morphological diversification of paleotropical Melastomateae. The inclusion of proposed paleoendemics such as Cailliella, Pseudosbeckia, Dionychastrum and Nerophila, will contribute to our understanding of the origin and spread of Melastomateae in Africa and Madagascar. Studies of floral morphology in the group will focus on stamen morphology and the evolution of heteranthery which has a direct (and probably fast) impact on the pollination syndrome and might represent one key character for diversification in the group. Our results will have a strong and direct impact on planned floristic treatments of the family, e.g. in the ongoing treatment of the Flora of Central Africa and in updating the Floras of Cameroon and Gabon, and therefore contribute to the floristic biodiversity survey of these regions.