The largest dinosaurs probably weighed somewhere between about 50 and 100 metric tons. All dinosaurs are reptiles, but not all reptiles are dinosaurs. Birds and crocodilians are each other's closest living relatives. Adult dipnoans incubate their eggs and exhibit parental care of the young. Ceratopsians probably used their horns to kill prey.
Crocodilians can vocalize and communicate even before they hatch from the egg.
Stegosaurus had a brain in its tail. The ancestral vertebrate was probably a predator. Sharks have highly developed sensors that can perceive even very weak electrical signals. Radar, magnetometry, Gamma rays, and acoustic tomography have all been employed by paleontologists to find dinosaurs. All gnathostomes are members of Osteichthyes, but not all osteichthyans are members of Gnathostomata.