Dissertation Research: Exploring the Temporal & Geographical Origins of Neotropical Diversity: Comparison of 32 Superspecies Groups in the Avian Families Galbulidae and Buccon

路易斯安那州立大学的Frederick Sheldon博士和Christopher Witt先生获得了一项拨款，用于研究新热带地区鸟类异常高度物种多样性的进化起源。尽管生物学家几个世纪以来就知道全球生物多样性的分布向热带倾斜，但人们对热带生物的系统发育关系以及可能导致它们广泛多样化的历史事件知之甚少。这项研究将使用博物馆收藏品对新热带鸟类的两个科--河豚和雅克马--的每一个可用物种和种群进行DNA比较。将使用将分子进化模型纳入DNA相似性测量的分析来重建进化谱系树。新物种形成和遗传分化的模式将在共享共同分布的相关群体中进行比较。通过这种方式，进化树将被用来推断进化谱系的年龄，并识别在所有分类水平上促成现代多样性的地质和气候因素。这一结果将对目前正在进行的关于长期地质稳定性与近期气候动荡对温带和热带鸟类动物群之间多样性差异的相对贡献的辩论产生影响。这项研究将涉及从广泛地理区域的许多相关生物收集DNA数据。结果将有两个主要好处：(1)推断物种多样化的进化原因；(2)确定保护优先事项。目前的分类几乎肯定不能充分代表热带生物的真正遗传多样性。需要像这样的遗传研究来识别隐秘或被忽视的物种，识别拥有显著遗传多样性的地区，并提出保护产品和进化过程的策略。

A grant has been awarded to Dr. Frederick Sheldon and Mr. Christopher Witt at Louisiana State University to study the evolutionary origins of the exceptionally high species diversity of birds found in the Neotropics. Although biologists have known for centuries that the global distribution of biodiversity is skewed towards the tropics, little is understood about the phylogenetic relationships of tropical organisms and the historical events that may have led to their extensive diversification. This study will use museum collections to make DNA comparisons among every available species and population of two families of Neotropical birds, the puffbirds and jacamars. Trees of evolutionary lineages will be reconstructed using analyses that incorporate models of molecular evolution into measurements of DNA similarity. Patterns of new species formation and genetic differentiation will be compared among related groups that share common distributions. In this way, evolutionary trees will be used to infer the ages of evolutionary lineages and to identify the geological and climatic factors that have contributed to modern day diversity at all taxonomic levels. The results will have implications for the ongoing debate regarding relative contributions of long-term geological stability versus recent climatic tumult to the disparity in diversity between temperate and tropical bird faunas. This study will involve collection of DNA data from many related organisms across a broad geographic region. The results will have two primary benefits: (1) inference of evolutionary causes of species diversification; and (2) identification of conservation priorities. Current classifications almost certainly do not adequately represent true genetic diversity in tropical organisms. Genetic studies such as this one are needed to identify cryptic or overlooked species, to recognize areas that harbor significant genetic diversity, and to suggest strategies for protecting both the products and the process of evolution.