Megalodon is an extinct species of shark that lived approximately 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. The two major interpretations are Carcharodon megalodon (under family Lamnidae) or Carcharocles megalodon (under family Otodontidae). Consequently, the scientific name of this species is commonly abbreviated C. megalodon in the literature.
C. megalodon is regarded as one of the largest and most powerful predators in vertebrate history, and likely had a profound impact on the structure of marine communities. Fossil remains suggest that this giant shark reached a maximum length of 14–18 metres (46–59 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.