The size of the megatooth shark, Otodus megalodon (Lamniformes: Otodontidae), revisited

ABSTRACT

Otodus megalodon (Lamniformes: Otodontidae) is a gigantic late Neogene shark that lived nearly worldwide in tropical-temperate regions. Its gigantic teeth have captivated imaginations of the scientific community and general public alike, where the most commonly cited maximum size range of O. megalodon in scientific literature is 18–20 m in total length (TL). In this study, I reexamined the ontogenetic development of teeth and the quantitative relationships between TL and the crown height of anterior teeth in the extant white shark, Carcharodon carcharias, with an ultimate goal to clarify the current state of the scientific understanding of the body size of O. megalodon. My study suggests that the use of upper anterior teeth is much preferred over lower anterior teeth when estimating TL. This study combined with previous studies suggests that the presently verifiable maximum TL estimates of O. megalodon (i.e. scientifically justifiable account based on museum specimens) are 14.2‒15.3 m TL, where individuals of O. megalodon exceeding 15 m TL must have been exceptionally rare. Nevertheless, O. megalodon can still be regarded as one of the largest carnivores, if not superpredators, that have ever lived on Earth.

KEYWORDS:

• Body size
• Elasmobranchii
• lamniform shark
• tooth
• white shark

Acknowledgments

Special thanks go to W. Simpson (FMNH) as well as N. Kohno and C. Sakata (NSM) for access to the three specimens illustrated in Figure 1. However, it must be noted that the three specimens represent a very small fraction of all the teeth of Otodus megalodon I encountered in numerous museum collections I visited over the last 35 years, and I sincerely thank all the museum staff and associates who accommodated my visits too numerous to list here. I should also note that there are still many other museum collections I have yet to visit, and it is also likely that many museums I visited in the past have expanded their collections since then. I thank anyone in advance for alerting me of any tooth specimens of O. megalodon in museum collections under public trust that are larger than those depicted in Figure 1. In addition, I thank P. C. Sternes for providing me some useful information, including the fiction novel accounts of the size of O. megalodon. I appreciate comments and suggestions made formally or informally by T. Badaut, S. J. Godfrey, C. Pimiento, T. R. Shimada, and an anonymous reviewer that improved the quality of this paper. I am indebted to the Department of Environmental Science and Studies and Department of Biological Sciences as well as the College of Science and Health at DePaul University for providing me various logistical support for my research programme for the past 20 years, including my past and present colleagues and students.

Disclosure statement

No potential conflict of interest was reported by the author.