Evolution and phylogenetic systematics of the sexually dimorphic orchid genus Cycnoches

作为为数不多的具有功能性二形花的兰花属之一，春兰属对了解兰科植物的生殖机制进化具有重要意义。石萝属包括约34种，分布在墨西哥南部到巴西和玻利维亚，主要栖息在低地潮湿的森林中。虽然这个群体在过去的几个世纪里吸引了几位科学家的注意，但人们对它的多样性和进化却知之甚少。该项目将产生质体和核系统发育，包括高达90%的已描述物种，特别强调那些发生在研究和采样较少的新热带地区的物种。将生成一个确定年代的系统发育，并对主要支系的生物地理进行重建。我们的主要目标是：1)确定海雀在亚部落水平上的精确系统定位及其物种的系统发育关系；2)通过下一代测序和化学分类学方法进行物种划分（重点是分类上具有挑战性的分类群，如Cycnoches egertonium物种复合体）；3)了解两性二态性的进化；4)阐明安第斯山脉抬升对石龙属主要分支进化的影响。结果将有助于一个完整的属专著。这项跨学科研究项目的成果将揭示重要的地理/生物事件的影响以及相关的新热带兰花群的进化。此外，它将作为一个模型来解决其他分类上存在问题和研究不足的兰花属，如裂兰属和模兰属。

As one of the few orchid genera with functionally sexual dimorphic flowers, Cycnoches (Catasetinae) species have special importance in understanding the evolution of reproductive mechanisms in Orchidaceae. The genus Cycnoches encompasses c. 34 species distributed from S Mexico to Brazil and Bolivia, which inhabit mostly lowland wet forests. Although this group has attracted the attention of several scientists during the last centuries, its diversity and evolution is poorly understood. A plastid and nuclear phylogeny will be generated in this project including up to 90% of the described species with special emphasis on those occurring in poorly studied and sampled regions of the Neotropics. A dated phylogeny will be generated and a reconstruction of the biogeography of major clades will be carried out. Our main goals are: 1) Determining the precise systematic placement of Cycnoches at the subtribal level and phylogenetic relationships of its species; 2) species delimitation by means of next generation sequencing and chemotaxonomical approaches (with emphasis on taxonomically challenging taxa such as the Cycnoches egertonianum species complex); 3) understanding the evolution of sexual dimorphism; and 4) elucidating the impact of the raising Andes in the evolution of the major clades of Cycnoches. The results will contribute to a complete monograph of the genus. The outcomes of this interdisciplinary research project will shed light on the influence of important geographic/biological events and the evolution of related hence poorly understood Neotropical orchid groups. Moreover, it will serve as a model to tackle other taxonomically problematic and understudied orchid genera such as Catasetum and Mormodes.