Deinosuchus

Crocodylians used to be thought of as “living fossils,” but their lineage, which Deinosuchus is a part of, has undergone clear substantial evolutionary changes. For example, Deinosuchus fossils show that the formidable reptile had an inflated nose and two cavernous holes at the tip of their snout—features unlike any modern crocodylians. These distinct morphological developments show that modern forms are not unchanged from their prehistoric relatives, which were more diverse in body shape and habits than today.