Cetacea Cetacea Cetacea () is a widely distributed and diverse clade of aquatic mammals that today consists of whales, dolphins, and porpoises. Cetaceans are carnivorous and finned. Most species live in the sea, some in rivers. The name is derived from the Latin "cetus" "whale", itself from the Greek κῆτος "kētos" "huge fish". There are around 89 extant species, which are divided into two groups or parvorders, the Odontoceti or toothed whales, a group of more than 70 species that includes the dolphins, porpoises, belugas, narwhals, sperm and beaked whales, and the Mysticeti or baleen whales, of which there are now
Ginkgo-toothed beaked whale Ginkgo-toothed beaked whale The ginkgo-toothed beaked whale ("Mesoplodon ginkgodens") is a poorly known species of whale even for a beaked whale, and was named for the unusual shape of its dual teeth. It is a fairly typical-looking species, but is notable for the males not having any scarring. Ginkgo-toothed beaked whales are more robust than most mesoplodonts, but otherwise look fairly typical. Halfway through the jaw, there is a sharp curve up where the ginkgo leaf-shaped tooth is. Unlike other species such as Blainville's beaked whale and Andrews' beaked whale, the teeth do not arch over the rostrum. The beak