megalodon, (Carcharocles megalodon), member of an extinct species of megatooth shark (Otodontidae) that is considered to be the largest shark, as well as the largest fish, that ever lived. Fossils attributed to megalodon have been found dating from the early Miocene Epoch (which began 23.03 million years ago) to the end of the Pliocene Epoch (2.58 million years ago). The word megalodon, a compound of Greek root words, means “giant tooth.”
Natural history
Distribution
Fossil remains of megalodon have been found in shallow tropical and temperate seas along the coastlines and continental shelf regions of all continents except Antarctica. During the early and middle parts of the Miocene Epoch (which lasted from 23 million to 5.3 million years ago), large seaways separated North America from South America and Europe and Asia from Africa and the Middle East, which likely facilitated movement from one ocean basin to another. Throughout the Miocene, megalodon distribution expanded from pockets located in the Caribbean and Mediterranean seas, in the Bay of Bengal, and along the coasts of California and southern Australia to encompass waters off the coasts of northern Europe, South America, southern Africa, New Zealand, and east Asia. During the Pliocene Epoch, however, megalodon’s geographic range contracted significantly, and it was extinct by the end of the epoch.
Physical features
Megalodon was the largest fish ever known, a designation based on discoveries of hundreds of fossil teeth, two vertebral columns, and a handful of individual vertebrae. Tooth-shape similarities between megalodon and modern great white sharks (Carcharodon carcharias) suggest that the two species may have been close relatives, and thus megalodon likely resembled that species in appearance—that is, as a bulky torpedo-shaped fish with a conical snout, large pectoral and dorsal fins, and a strong crescent-shaped tail. Estimates of body length are calculated using the statistical relationship between the size of megalodon’s fossil teeth and the teeth and body mass of modern white sharks and other living relatives. This data suggests that mature adult megalodons had a mean length of 10.2 metres (about 33.5 feet), the largest specimens measuring 17.9 metres (58.7 feet) long. Some scientists, however, contend that the largest forms may have measured up to 25 metres (82 feet) long. Studies estimate that adult body mass ranged from roughly 30 metric tons (1 metric ton = 1,000 kg; about 66,000 pounds) to more than 65 metric tons (about 143,000 pounds), adult females being larger (in both length and mass) than adult males.
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