Dissertation Research: A Hierachical Analysis of PhylogenticRelationships in Bufonidae

蟾蜍科的真蟾蜍是研究物种多样化模式和过程的丰富资源，但如果不了解该科成员之间的系统发育关系，就无法发挥其潜力。目前还没有可靠的蟾蜍科系统发育假说。虽然这个科的庞大规模阻止了对物种水平的系统发育的估计，但这种程度的细节并不需要回答许多问题。相反，我们需要的是了解这个科的主要亚分支之间的系统发育关系，以及最近分化的物种的小分支之间的系统发育关系。本研究代表了一个层次的方法来阐明系统发育关系在蟾蜍科和应用这一信息的物种多样化的理解。来自科内两个分化水平上的代表性物种的DNA序列数据：在远亲物种之间和在一个物种群内，将用于估计这些水平上的系统发育关系。通过对远亲分类群的系统发育假设，将解决两个问题：1)大陆间的生物地理关系和2)形态创新。在一个物种群的系统发育关系的假设下，物种形成的模式和过程将被研究。

True toads of the large family Bufonidae are a rich resource for studying pattern and process in species diversification, but the potential cannot be realized without an understanding of the phylogenetic relationships among the family's members. There is no robust phylogenetic hypothesis available for Bufonidae. While the large size of the family prohibits the estimation of a phylogeny resolved to the species level, this level of detail is not required to answer many questions. Instead what is needed is an understanding of the phylogenetic relationships among the major subclades of the family and within small clades of recently diverged species. This study represents a hierarchical approach to the elucidation of phylogenetic relationships within Bufonidae and the application of this information to an understanding of species diversification. DNA sequence data from representative species at two levels of divergence within the family: among distantly related species and within one species group, will be used to estimate phylogenetic relationships at these levels. With a phylogenetic hypothesis for the distantly related taxa, two questions will be addressed: 1) biogeographic relationships among continents and 2) morphological innovation. With a hypothesis of phylogenetic relationships within one species group, patterns and processes of speciation will be studied.