Phylogeny and Biogeography of the Dichrostachys Group (Mimosideae Leguminosae) in Madagascar: Evidence from Morphological and Molecular Studies

卢科马达加斯加的Dichrostachys组（含羞草亚科：豆科植物）的系统发育和植物地理学：来自形态学和分子研究的证据。马达加斯加生物群是地球上最多样化的生物群之一，无论是使用物种的原始数量，独特特征还是系统发育位置来衡量生物多样性。据报道，在一个长约1000英里、宽约360英里的地区，估计有超过10，000种开花植物，而且大量的特有物种往往具有在其他地区原生的相关类群中看不到的极端形态创新。因此，马达加斯加提供了一个理想的系统，在其中调查影响物种形成和形态多样性和精心制作的因素。由三个属组成的含羞草属豆科植物，Dichrostachys组广泛分布在马达加斯加，大约30种中只有三种是该岛特有的。该小组提供了一个模型系统，用于调查马达加斯加植物的进化，因为有大量的物种，因为它们广泛分布在马达加斯加的干燥，季节性干燥和潮湿的森林中。基于分子和形态学数据的系统发育分析将用于解决与系统学、授粉和植物地理学有关的问题。属的界限在Dichrostachys组中一直存在争议，而单系发生将作为定义单系属的基础。传粉者的转变和传粉者与花序颜色和其他花卉性状的变化的相关性将进行研究。特别感兴趣的将是一个引进的物种在马达加斯加和南非本土人口的传粉者的比较。特别是这将使我们能够探索这样的问题：是伴随着传粉者的转变花序颜色的变化？个体发生的颜色变化与传粉者的转变有关吗？该系统还将用于马达加斯加特有地区的地理学研究。具体而言，拟议的海洋地理研究将探讨物种形成和地质过程之间的关系，解决的问题，如：是否有土壤类型和物种形成之间的相关性在马达加斯加？这是一个可以在不相关的群体中测量的普遍现象吗？物种形成和地质事件之间是否存在着对应关系，表明了物种形成的一般模式？这项调查也将有助于主要的描述性数据的形式，一个专着，传粉者的计数，并详细绘制物种分布。物种分布的详细绘图可用于证实或反驳最近利用卫星图像分类的主要植被类型的概括。该Dichrostachys组从来没有专著，有新的物种科学以及新的信息，以前描述的物种。马达加斯加的生物群目前是世界上受威胁最严重的生物群之一，迫切需要开展这项工作。

9726981 Luckow Phylogeny and biogeography of the Dichrostachys group (Mimosoideae:Leguminosae) in Madagascar: evidence from morphological and molecular studies. The Madagascan biota qualifies as one of the most diverse on earth, whether one measures biodiversity using raw numbers of species, unique features, or phylogenetic position. Estimates of over 10,000 species of flowering plants have been reported from an area about 1000 miles long and 360 miles wide, and the large number of endemic species often possess extreme morphological innovations not seen in related taxa native to other regions. Thus, Madagascar offers an ideal system in which to investigate the factors influencing both speciation and morphological diversity and elaboration. An assemblage of three genera of mimosoid legumes, the Dichrostachys group has radiated widely throughout Madagascar, with all but three of approximately 30 species endemic to the island. The group provides a model system for investigating the evolution of Malagasy plants both because there are a large number of species and because they are widely distributed throughout the dry, seasonally dry, and moist forests of Madagascar. Phylogenetic analyses based on molecular and morphological data will be used to address questions relevant to systematics, pollination, and biogeography. Generic boundaries have been controversial in the Dichrostachys group, and the phylogeny will serve as a basis to define monophyletic genera. Pollinator shifts and correlations of pollinators with changes in inflorescence color and other floral traits will be examined. Of special interest will be the comparison of the pollinators of one introduced species both in Madagascan and in native South African populations. In particular this will permit us to explore such questions as: are changes in inflorescence color accompanied by a shift in pollinators? Are ontogenetic color changes associated with pollinator shifts? The phylogeny will also be used in biogeographic stu dies of areas of endemism within Madagascar. Specifically, the proposed biogeographic study will explore the relationship between speciation and geological processes, addressing questions such as: Is there a correlation between soil type and speciation in Madagascar? Is this a general phenomenon that can be measured across unrelated groups? Is there correspondence of phylogenies and geologic events indicating a general pattern of speciation through time? This investigation also will contribute primary descriptive data in the form of a monograph, an enumeration of pollinators, and the detailed mapping of species distributions. The detailed mapping of species distributions can be used to corroborate or refute generalizations about the primary vegetation types that recently have been classified using satellite imagery. The Dichrostachys group has never been monographed and there are species new to science as well as new information on previously described species. The biota of Madagascar is currently one of the most threatened in the world and the need for this work is urgent.