You are quoting me as if you found some population that doesn't change with sweeping changes in the environment. What sweeping changes in the environment that crocodiles live in have occurred between the time those fossils were alive and now?
Do you think that because the environment the fossils are found in is different than the environment that the crocodiles live in now, that they used to live in that environment and now live in the water?

Our planet has been shaken by five major extinctions in the four billion year history of life. The first, 450 million years ago, occurred shortly after the evolution of the first land-based plants and 100 million years after the Cambrian Explosion of animal life beneath the seas.

The second extinction spasm came 350 million years ago, causing the formation of coal forests. Then the Earth experienced two mass extinctions during the Triassic period, between 250 and 200 million years ago. The fifth mass extinction, probably caused by a giant meteor collision, occurred 65 million years ago, at the end of the Cretaceous period, and ended the reptilian dominance of the Earth. This led to the current mammalian domination of the Earth.

Estimates of the number of major mass extinctions in the last 540 million years range from as few as five to more than twenty. These differences stem from the threshold chosen for describing an extinction event as "major", and the data chosen to measure past diversity.