Dinosaurs a global perspective

In more recent times, this approach has been applied much more broadly and in a much more ambitious way. Paul Upchurch of University College London and Craig Hunn at Cambridge hoped to explore the entire family tree of the Dinosauria for evidence of similarities in patterns of stratigraphic ranges and cladistic patterns by looking at large numbers of dinosaurs. These were compared to the currently established distributions of the continents at intervals through the entire Mesozoic Era. An attempt was being made to find out whether an overall signal did emerge that was suggestive of a tectonic influence on the evolutionary history of all dinosaurs.

Despite the inevitable 'noise' in the system resulting largely from the incompleteness of the fossil record of dinosaurs, it was heartening to note that statistically significant coincident patterns emerged within the Middle Jurassic, the Late Jurassic, and the Early Cretaceous intervals. This indicates that tectonic events do, as expected, play some role in determining where and when particular groups of dinosaurs flourished. What is more, this effect has also been preserved in the stratigraphic and geographic distributions of other fossil organisms, so the evolutionary history of great swathes of organisms was effected by tectonic events and the imprint is still with us today. In a way, this is not new. I need only point to the unusual distribution of marsupial mammals (found only in the Americas and Australasia today), and the fact that distinct areas of the modern world have their own characteristic fauna and flora. What this new research suggests is that we may well be able to trace the historical reasons for these distributions far more accurately than we had supposed possible.

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