Mesozoic neoselachians (Chondrichthyes, Elasmobranchii): Patterns of phylogeny, biogeography and diversity in a changing world

现代新脊椎动物是一个定义明确的类群，包括所有的鲨鱼、溜冰鞋和银鱼。它们通过骨骼的突触同形而结合在一起。相反，由于软骨骨架的保存在化石记录中是个例外，所以新腰椎动物化石主要是通过它们的牙齿来识别的。因此，许多(如果不是大多数的话)新塞拉目化石的分类是模糊的。从早三叠世到晚白垩世，在几个地方发现了中生代新塞拉亚的骨骼遗骸。这些标本对于了解新塞拉目动物的早期进化和多样化是必不可少的。在该项目的框架内，对所有这些标本进行了检查、分析和修改，并与现有的分类群进行了比较。化石和现存化石的相互关系将用现代系统发育学方法进行仔细研究。化石类群的多样性和古生物地理关系将在系统发育分析的基础上重建，同时也将利用相似性测量。此外，还利用分子序列重建了现代新脊椎动物之间的相互关系。所有分析的结果被比较和结合起来，以建立一个关于新脊椎动物进化、多样化和相互关系的全面假说。仅以牙齿为基础的分类群的可靠性将受到辩论。

Modern neoselachians are a well-defined group including all sharks, skates, and rays. They are united by synapomorphies of the skeleton. Conversely, fossil neoselachians are recognized primarily by their teeth since the preservation of the cartilaginous skeleton is the exception in the fossil record. Consequently, the taxonomy of many if not most fossil neoselachians is obscure. Skeletal remains of Mesozoic neoselachians are known from several localities ranging from the Early Triassic to the Late Cretaceous. These specimens are essential for understanding the early evolution and diversification of neoselachians. In the framework of the project, all these specimens are examined, analysed, and revised in comparison with extant taxa. The interrelationshipsof fossil and extant will be scrutinized using modern phylogenetic methods. The diversity and palaeobiogeographic relationships of fossil taxa will be recontructed based on phylogenetic analyses but also using similarity measurements. In addition, the interrelationships of modern neoselachians are recontructed using molecular sequences. The results of all analyses are compared and combined to estabish a comprehensive hypothesis of neoselachian evolution, diversification, and interrelationships. The reliability of taxa based on teeth alone will be debated.