The Break-up of Pangaea: Jurassic and Cretaceous
Published:January 01, 2008
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.
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Fishes and the Break-up of Pangaea
This volume, in honour of Peter L. Forey, is about fishes as palaeobiogeographic indicators in the Mesozoic and Cenozoic. The last 250 million years in the history of Earth have witnessed the break-up of Pangaea, affecting the biogeography of organisms. Fishes occupy almost all freshwater and marine environments, making them a good tool to assess palaeogeographic models.
The volume begins with studies of Triassic chondrichthyans and lungfishes, with reflections on Triassic palaeogeography. Phylogeny and distribution of Late Jurassic neoselachians and basal teleosts are broached, and are followed by five papers about the Cretaceous, dealing with SE Asian sharks, South American ray-finned fishes and coelacanths, European characiforms, and global fish palaeogeography. Then six papers cover Tertiary subjects, such as bony tongues, eels, cypriniforms and coelacanths.
There is generally a good fit between fish phylogenies and the evolution of the palaeogeographical pattern, although a few discrepancies question details of current palaeogeographic models and/or some aspects of fish phylogeny.