Phylogeny and Evolution of Caesalpinioid Legumes

豆科(或豆科或豆科)是开花植物的第三大科，也是经济上第二重要的科。豆类从巨大的热带雨林树木到沙漠栖息地的一年生草本植物。在传统上公认的三个亚科中，凯撒亚科、含羞亚科和凤蝶亚科是最不为人所知的，因为它主要局限于热带生境。因此，海南豆科植物之间的进化关系鲜为人知，对特定属的认识也经常存在争议。Herendeen博士和他在加拿大和英国的同事们之前的工作已经建立了Caesalpinioideae的一般系统发育框架，该框架将用于进一步研究形态、分类学和系统发育。目前的形态和分子数据表明，几个海鞘类谱系的基位置比含羞亚科和凤蝶亚科的都要多。因此，基于进化关系的家族分类系统将不会将凯萨皮亚目视为一个单一的自然单位，而是将其视为几个早期分枝的谱系。Cesalpiniae豆科植物有多少不同的谱系，相对于含羞草和Pililionys，它们应该在什么水平上被识别，Cesalpiniae属之间有什么关系，我们可以从形态进化的模式中看出什么？这些问题构成了研究的核心。这项研究的主要目标是基于对形态数据和DNA序列数据的分析，产生一个包括大约160个属的豆科豆科植物的分类。为了实现这一目标，将在马达加斯加、南美洲和东南亚进行实地工作，以获取尽可能多的失踪属的材料。研究人员还将研究草本植物的收集，并准备解剖样本，为分子数据集中包括的所有物种的形态特征评分。他们将使用系统发育的结果来产生一个修订的分类和识别亚科、部落和属的所有凯萨皮涅类豆类植物的检索表。有了强大的系统发育和以标本为基础的形态数据集，他们将能够探索关于形态进化模式的系统发育的含义。此外，关于各种豆类化石的数据将与结果整合在一起。这些化石可以用来记录支系的最小年龄，也可以作为生物地理学研究的历史数据点。此外，分子时钟技术将被用来估计分支的年龄。这项研究中产生的数据将使豆科成为一个理想的类群，在其中试验新的方法来估计支系的年龄，评估分类多样化和分子进化的速度。

The Leguminosae (or Fabaceae - the legume or bean family) is the third largest family of flowering plants, and the second most important family economically. Legumes range from giant rain forest trees to tiny herbaceous annuals of desert habitats. Of the three traditionally recognized subfamilies, Caesalpinioideae, Mimosoideae, and Papilionoideae, the Caesalpinioideae is the most poorly known because it is largely confined to tropical habitats. As a consequence, evolutionary relationships among caesalpinioid legumes are poorly known and the recognition of particular genera is often in dispute. Previous work by Dr. Herendeen and his colleagues in Canada and England has developed a general phylogenetic framework for Caesalpinioideae, which will be used to further research on morphology, taxonomy, and phylogeny. Current morphological and molecular data show that several caesalpinioid lineages have more basal positions than either the Mimosoideae or Papilionoideae. Thus a classification system for the family based on evolutionary relationships would not recognize the caesalpinioids as a single natural unit but as several early-branching lineages. How many distinct lineages of caesalpinioid legumes are there, at what level should they be recognized relative to mimosoids and papilionoids, what are the relationships among caesalpinioid genera, and what can we discern about patterns of morphological evolution? These questions form the core of the study. The primary goal of this research is to produce a classification that includes all ca. 160 genera of caesalpinioid legumes based on analyses of data from morphology and DNA sequence data. To achieve this, field work will be conducted in Madagascar, South America, and SE Asia to obtain material of as many of the missing genera as possible. The investigators will also study collections in herbaria and prepare anatomical samples to score morphological characters for all species included in the molecular data set. They will use the phylogenetic results to produce a revised classification and identification key to subfamilies, tribes, and genera for all caesalpinioid legumes. With a robust phylogeny and a specimen-based morphological data set, they will be able to explore the implications of the phylogeny with respect to patterns of morphological evolution. In addition, data on a diverse array of fossil legumes will be integrated with the results. The fossils may be used in documenting minimum ages of clades and as historical data points for biogeographic studies. In addition, molecular clock techniques will be used to estimate ages of clades. The data generated in this study will make the Leguminosae an ideal group in which to experiment with new methods in estimating ages of clades and assessing rates of taxonomic diversification and molecular evolution.