Evolution and adaptive radiation of dog-fish sharks (Chondrichthyes, Squaliformes)

点击翻译按钮获取中文摘要

The interrelationships and evolution of squaliform sharks are controversially discussed and the processes underlying their radiation in the deep-sea are unknown. Squaliform sharks are wide-spread and constitute a monophyletic group with a fossil record ranging back into the Early Cretaceous. Their fossil record consists almost completely of isolated teeth, only few skeletal remains are known from the Lebanese Late Cretaceous. In this study, the phylogeny of extant and fossil squaliforms is re-examined for the first time using a combination of dental, meristic, and molecular data. Although the separate data sets display high potential for reconstructing phylogenetic relationships within squaliforms, no detailed study concerning the potential of individual data sets in combination has been carried out so far. The radiation of selected speciose groups (e.g., Etmopteridae, Squalidae) will be analysed with modern techniques for gaining better insights into the timing and pattern of processes underlying adaptation and speciation events and to develop general models with relevance to other groups e.g., deep-water carcharhiniform sharks.