Researchers: The findings show that the limited diversity of crocodiles and their apparent lack of evolution is a result of a slow evolutionary rate. It seems the crocodiles arrived at a body plan that was very efficient and versatile enough that they didn’t need to change it in order to survive. (They cite “punctuated equilibrium.”)
Note: Researchers: “It was clear from the start of the study that extinct species showed a different pattern, including species with many specializations not seen today. One such specialization is a feature known as heterodonty: regionalized differences in tooth size or shape.” Maybe the crocodiles had an arsenal of potential adaptations in their genes.
Researcher: Transitions between land, sea, and freshwater were more frequent than we thought, and the transitions were not always land-to-freshwater or freshwater-to-marine. [Once they were really big, they could take over what they wanted to.]