Cooler waters created super-sized Megalodon, latest study shows

The Megalodon shark grew to larger sizes in cooler environments than in warmer areas, according to a new study.

The body size patterns of the Otodus megalodon, the fossil shark that lived nearly worldwide roughly 15 to 3.6 million years ago, have been reexamined by a team of researchers. The journal Historical Biology has a new study in it.

Otodus megalodon is often portrayed as a giant shark in novels and films, but in reality it is only known from the teeth and bones in the fossil record. The new study looked at the published records of geographic occurrences of Megalodon teeth.

Our findings suggest a previously unrecognized body size pattern for the fossil shark, notably following a geography-driven ecological pattern known as Bergmann's rule.

Bergmann's rule states that larger animals thrive in cooler climates because their size helps them retain heat more efficiently than smaller animals.

Smaller Megalodon teeth can be found at some Megalodon sites, which were previously identified as possible nursery areas of the fossil shark. The nursery areas for Megalodon are located near the equator, and it is possible that they were used to raise young sharks. But our study shows that fossil localities consisting of smaller Megalodon teeth may instead be a product of individual sharks attaining smaller overall body sizes simply as a result of warmer water, said coauthor Harry Maisch, a faculty member at Bergen Community College and Fairleigh Dickinson University in New Jersey.

The idea of this new study was born during a recent fishing trip to the Florida Keys by the lead author, his family and me, stemming from a basic question: where do large fish live? The results of this study have important implications for understanding how modern climate change is rapidly speeding up marine habitat shifts to more polar latitudes in apex predators such as sharks.

The main conclusion of the study is that not all Megalodon individuals grew to gigantic sizes equally. The common notion that the species reached 20 m TL should be applied to populations that lived in cooler environments.

More information: Revisiting body size trends and nursery areas of the Neogene megatooth shark, Otodus megalodon (Lamniformes: Otodontidae) reveals Bergmann's rule possibly enhanced its gigantism in cooler waters, Historical Biology, DOI: 10.1080/08912963.2022.2032024 , www.tandfonline.com/doi/full/1 … 8912963.2022.2032024 Citation: Cooler waters created super-sized Megalodon, latest study shows (2022, March 6) retrieved 6 March 2022 from https://phys.org/news/2022-03-cooler-super-sized-megalodon-latest.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.