Evolution of cetaceans "Caperea marginata") all have derived characteristics presently unknown in any cetothere and vice versa (such as a sagittal crest). The adaptation of echolocation occurred when toothed whales (Odontoceti) split apart from baleen whales, and distinguishes modern toothed whales from fully aquatic archaeocetes. This happened around 34 million years ago in a second cetacean radiation. Modern toothed whales do not rely on their sense of sight, but rather on their sonar to hunt prey. Echolocation also allowed toothed whales to dive deeper in search of food, with light no longer necessary for navigation, which opened up new food sources. Toothed whales
Toothed seadevil what the toothed seadevil feeds upon and how. It has been suggested that their external jaw teeth serve to entangle soft-bodied invertebrates. The males are fully parasitic, using tooth-bearing denticles at the tips of their jaws to attach to the female and their tissues and blood vessels becoming fused with that of the female. Toothed seadevil The toothed seadevil, spiny seadevil or netbeard seadevil, "(Neoceratias spinifer)", is a rarely seen deep-sea anglerfish found in the mesopelagic and bathypelagic zones of the western central Pacific Ocean. It is the only species in the family Neoceratidae, and is unique amongst the deep-sea