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

• Applicant: Professor Dr. Jürgen Kriwet
• Subject Area: Palaeontology
• Term: from 2004 to 2007
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5415100

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.

• DFG Programme: Research Grants