Nature covers GeoBio-Center study on dinosaur body size
Many researchers have suggested that the maximum sizes of Mesozoic dinosaurs and other land-living vertebrates were driven by changing environmental conditions. To test this idea, the team collected data on the body size of dinosaurs and other vertebrates including mammalian ancestors (synapsids) over 100 million years of time, from the Permian to the Jurassic. They then used rigorous statistical models to compare changes in body size with changes in atmospheric composition and land area, and found no significant correlations. Similarly, no correlations were found between changes in these environmental variables and a dataset on maximum mammal body size during the 65 million years from the Palaeocene to the Pleistocene. Instead, the team support the hypothesis that biological factors, such as growth rates and breathing mechanisms, are more important than environmental factors in determining the maximum sizes that individual groups of vertebrates achieved.
This research was covered by Nature News: http://www.nature.com/news/dinosaurs-grew-to-outpace-their-young-1.10465
Roland Sookias and Richard Butler are supported by a Emmy-Noether Award from the DFG.
Paper: Sookias, R.B., Benson, R.B.J. & Butler, R.J. 2012. Biology, not environment, drives major patterns in maximum tetrapod body size through time Biology Letters http://dx.doi.org/10.1098/rsbl.2012.0060 (2012).