The biodiversity of land-dwelling crocodiles and their closest relatives has been shown to correspond to global climate. This is particularly pronounced during the late Neogene (7 – 2.5 million years ago) when global climate continually cooled until the onset of significant northern hemisphere glaciations at 2.5 million years ago. What would be interesting is that at a finer temporal resolution the Neogene shows many intervals of increased global temperatures; do crocodylians respond to these by expanding their ranges into the temperate regions of the world?
The fossil record of crocodylians and their relatives (pseudosuchians) reveals a rich evolutionary history, prompting questions about causes of long-term decline to their present-day low biodiversity. We analyse climatic drivers of subsampled pseudosuchian biodiversity over their 250 million year history, using a comprehensive new data set. Biodiversity and environmental changes correlate strongly, with long-term decline of terrestrial taxa driven by decreasing temperatures in northern temperate regions, and biodiversity decreases at lower latitudes matching patterns of increasing aridification.