The megalodon ( /ˈmɛɡələdɒn/ meg-ə-lə-don; meaning "big tooth", from Greek μέγας (mega, "big") and ὀδούς (odon, "tooth")) is an extinct species of shark that lived roughly from 28 to 1.5 million years ago, during the Cenozoic Era (late Oligocene to early Pleistocene).
The taxonomic assignment of C. megalodon has been debated for nearly a century, and is still under dispute with two major interpretations; Carcharodon megalodon (under family Lamnidae) or Carcharocles megalodon (under family Otodontidae).Consequently, the scientific name of this species has been commonly abbreviated to C. megalodon in literature.
C. megalodon is regarded as one of the largest and most powerful predators in vertebrate history. C. megalodon likely had a profound impact on structuring of the marine communities. Fossil remains indicate that this giant shark reached a total length (TL) of more than 16 metres (52 ft), and also affirm that it had a cosmopolitan distribution. Scientists suggest that C. megalodon looked like a stockier version of the great white shark, Carcharodon carcharias, in life.