Megalodon:

The Megalodon was a shark with a maximum length of 24.2 metres (79 ft) that lived 23 to 3.6 million years ago in the Early Miocene to the Pliocene. Their jaws could exert a bite force of up to 108,500 to 182,200 newtons (24,400 to 41,000 lb.). Its diet consisted of large prey, such as dolphins, small whales, cetotheres, squalodontids, sperm whales, bowhead whales, rorquals, seals, sirenians, and sea turtles. The shark was an opportunist and piscivorous; it would have gone after smaller fish and other sharks. The juveniles inhabited warm coastal waters and their diet was fish and small whales. When attacking its prey, the Megalodon would have targeted the heart and lungs. Mature male megalodon would have weighed upward of 12.6 to 33.9 metric tons (13.9 to 37.4 short tons), and mature females would have been 27.4 to 59.4 metric tons (30.2 to 65.5 short tons). The creature would have gone 18 kilometers per hour (11 mph). Its size was influenced by the evolution of regional endothermy (mesothermy) which would have increased its metabolic rate and swimming speed. The Megalodon would have also been ectothermic. Their large size was also due to intrauterine cannibalism, this would require the mother to attain even greater size as well as caloric requirements, which would have promoted endothermy. Males would have needed to keep up with female size in order to still effectively copulate which involved latching onto the female with claspers, like modern cartilaginous fish. The dental structure of this creature is characterized as having a triangular shape, a robust structure, a large size, fine serrations, a lack of lateral denticles, and a visible V-shape where the root meets the crown. The teeth meet the jaw at a steep angle. The teeth are anchored by connective tissue fibers, and the roughness of the base would have added to the mechanical strength. The lingual side of the tooth was convex; the labial side was mildly convex. The anterior teeth were nearly perpendicular to the jaw and symmetrical, whereas the posterior teeth were slanted and asymmetrical. The size of the teeth is over 180 millimeters (7.1 inches) in slant height. Megalodon had four kinds of teeth in its jaws, consisting of the anterior, intermediate, lateral, and posterior. The Megalodon's intermediate tooth is technically an upper anterior and is termed as "A3" as it is fairly symmetrical and does not point mesially. The creature had a very robust dentition; having over 250 teeth in its jaws, spanning 5 rows. The jaw spanned 2 metres (6.6 ft.) across. The teeth were serrated to improve efficiency in cutting through flesh or bone. The jaws could be opened at a 100° angle. As with all sharks, the skeleton of the megalodon was formed of cartilage rather than bone. The vertebrae of the creature would have had over 200 centra which would have individually ranged from 55 millimeters (2.2 in) to 155 millimeters (6 inches) in diameter. The shark had a spiral valve. The distribution of the instances of Megalodon is a cosmopolitan distribution under 55° N, although it preferred subtropical to temperate latitudes. Its tolerated temperature range was 1–24 °C (34–75 °F).  It had the capacity to endure uncharacteristically low temperatures due to mesothermy. The Megalodon inhabited a wide range of marine environments including shallow coastal waters, areas of coastal upwelling, swampy coastal lagoons, sandy littorals, and offshore deep-water environments; it exhibited a transient lifestyle. Adult megalodon were not abundant in shallow water environments and mostly inhabited offshore areas. Megalodon would move between oceanic and coastal waters, particularly in different stages of its life cycle. The shark's lifespan would have typically lasted 88 to 100 years. The Phylogenies of this species are of the Kingdom Animalia, the Phylum Chordata, the Class Chondrichthyes, the Order Lamniformes, the Family †Otodontidae, the Genus †Otodus, the Species †Otodus megalodon.