When did Carcharocles megalodon become extinct? A new analysis of the fossil record.

Christopher F. Clements,Catalina Pimiento

doi:10.1371/journal.pone.0111086

Abstract

Carcharocles megalodon (“Megalodon”) is the largest shark that ever lived. Based on its distribution, dental morphology, and associated fauna, it has been suggested that this species was a cosmopolitan apex predator that fed on marine mammals from the middle Miocene to the Pliocene (15.9–2.6 Ma). Prevailing theory suggests that the extinction of apex predators affects ecosystem dynamics. Accordingly, knowing the time of extinction of C. megalodon is a fundamental step towards understanding the effects of such an event in ancient communities. However, the time of extinction of this important species has never been quantitatively assessed. Here, we synthesize the most recent records of C. megalodon from the literature and scientific collections and infer the date of its extinction by making a novel use of the Optimal Linear Estimation (OLE) model. Our results suggest that C. megalodon went extinct around 2.6 Ma. Furthermore, when contrasting our results with known ecological and macroevolutionary trends in marine mammals, it became evident that the modern composition and function of modern gigantic filter-feeding whales was established after the extinction of C. megalodon. Consequently, the study of the time of extinction of C. megalodon provides the basis to improve our understanding of the responses of marine species to the removal of apex predators, presenting a deep-time perspective for the conservation of modern ecosystems.

Highlights

Carcharocles megalodon (‘‘Megalodon’’) was the largest shark that ever lived [1]
Based on the known age range of Carcharocles megalodon, we considered any post-Miocene occurrence as part of the most recent records of the species, and treated them as historic sightings to be used in the Optimal Linear Estimation (OLE) calculation
Our analysis suggests that the extinction of Carcharocles megalodon most likely occurred around Pliocene–Pleistocene boundary (,2.6 Ma, modal value)

Summary

Introduction

Carcharocles megalodon (‘‘Megalodon’’) was the largest shark that ever lived [1]. Based on its dentition, distribution and associated fauna, it has been suggested that this species could reach up to 18 m of total length, was a cosmopolitan apex predator and fed on cetaceans [1,2,3,4,5,6,7]. Its gigantic size and abundant fossil record has made this shark a charismatic example of extinct marine megafauna. Despite its popularity and widespread fossil record, remarkably little is known about its extinction. It has been widely stated in the literature that the extinction of apex predators can trigger cascading effects through entire food webs and impact ecosystem composition and function [8,9]. It has been demonstrated that the elimination of large sharks produces broad marine ecosystem degradation [10]. Apex predators, especially large sharks, are significantly declining throughout the global oceans [11,12]. The study of the extinction of apex predatory sharks is of significant interest

Methods

Results

Conclusion