[js1138]

Somatic change is constrained by selection. You haven't given a reference for the mutation rate.

[CarolinaGuitarman]

He doesn't seem to have a grasp of what a species is either...

[js1138]

Lest I be misunderstood, populations can undergo changes in the genome without displaying large outward changes in body conformation.

Second, it is possible for a species to reach a point of specialization at which nearly all change is detrimental. At such a point, any mutation that would produce a change in body conformation would be at a reproductive disadvantage, and would be selected out.

You have made a broad statement that mutations in alligators and crocodiles occur at a reduce rate. I am not aware of any research confirming this. It is up to you to defend your statement.