Addressing this question requires a densely sampled marine vertebrate fossil record in concert with a robust geochronologic framework.
Robert W. Boessenecker, Dana J. Ehret, Douglas J. Long, Morgan Churchill, Evan Martin,Sarah J. Boessenecker 2019, 'The Early Pliocene extinction of the mega-toothed shark Otodus megalodon: a view fromthe eastern North Pacific', PeerJhttps://peerj.com/articles/6088.pdf. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)