Diversity and biogeography patterns of Late Jurassic neoselachians (Chondrichthyes, Elasmobranchii)

The regional diversity and biogeographic patterns of Late Jurassic neoselachians at genus level in Europe were analysed based on samples and an extensive literature survey of about 40 localities ranging from the Oxfordian to Tithonian. The simple completeness metric (SCM) displays a quite good fossil record of neoselachians in the Late Jurassic with a peak in the Kimmeridgian. The origination, extinction, diversification and turnover rates were calculated for every stage and indicate that background origination occurred in the Oxfordian and Kimmeridgian with no disappearance of genera. In the Tithonian, background extinction is the main factor for neoselachian diversity decline. The decline in neoselachian diversity at the end of the Jurassic is most probably related to reduced habitats in the course of major regression events, establishment of physical barriers, and climatic changes. Faunal assemblages are quite uniform and mostly agree well with the contemporaneous palaeogeographic situation. Our analyses indicate that both vicariance and dispersal were important processes in the biogeographic pattern of Late Jurassic neoselachians.