DOI: 10.5061/dryad.6q5t4
title: Data from: Body-size trends of the extinct giant shark Carcharocles megalodon: a deep-time perspective on marine apex predators

description: The extinct shark Carcharocles megalodon is one of the largest marine apex
 predators ever to exist. Nonetheless, little is known about its body-size
 variations through time and space. Here, we studied the body-size trends
 of C. megalodon through its temporal and geographic range to better
 understand its ecology and evolution. Given that this species was the last
 of the megatooth lineage, a group of species that shows a purported size
 increase through time, we hypothesized that C. megalodon also displayed
 this trend, increasing in size over time and reaching its largest size
 prior to extinction. We found that C. megalodon body-size distribution was
 left-skewed (suggesting a long-term selective pressure favoring larger
 individuals), and presented significant geographic variation (possibly as
 a result of the heterogeneous ecological constraints of this cosmopolitan
 species) over geologic time. Finally, we found that stasis was the general
 mode of size evolution of C. megalodon (i.e., no net changes over time),
 contrasting with the trends of the megatooth lineage and our hypothesis.
 Given that C. megalodon is a relatively long-lived species with a widely
 distributed fossil record, we further used this study system to provide a
 deep-time perspective to the understanding of the body-size trends of
 marine apex predators. For instance, our results suggest that (1) a
 selective pressure in predatory sharks for consuming a broader range of
 prey may favor larger individuals and produce left-skewed distributions on
 a geologic time scale; (2) body-size variations in cosmopolitan apex
 marine predators may depend on their interactions with geographically
 discrete communities; and (3) the inherent characteristics of shark
 species can produce stable sizes over geologic time, regardless of the
 size trends of their lineages.
description: Pimiento&Balk.DatasetCarcharocles megalodon tooth measurements and body size estimations from different geologic formations around the world.Pimiento and Balk.SupplementaryOnline.xlsxPimiento&Balk.TableS1Descriptive statistics of Carcharocles megalodon crown height (mm) through time. Significant values in bold. Codes: P =Pliocene (5.33-2.58 Ma), LM = late Miocene (11.61-5.33 Ma), MM = middle Miocene (15.97-11.61 Ma).Pimiento&Balk.TableS2Statistical comparisons of Carcharocles megalodon crown height (mm) trends through time across space. Significant values in bold. P =Pliocene (5.33-2.58 Ma), LM = late Miocene (11.61-5.33 Ma), MM = middle Miocene (15.97-11.61 Ma).Pimiento&Balk.TableS3Model fitting results for Carcharocles megalodon crown height trends. Largest Akaike weigh (best fit) in bold.Pimiento&Balk.Fig.S1Carcharocles megalodon tooth-size distributions (note log10 scale). The density curve is in grey. A, General body-size distribution. B, Body-size distributions through time.Pimiento&Balk.Fig.S2Geographic trends in Carcharocles megalodon tooth size. A, Tooth size by latitude. The dashed line represents best-fit linear regression model. Black dots represent the middle Miocene (MM) samples, grey dots the late Miocene (LM) samples, and white dots the Pliocene (P) samples. B, Boxplot showing tooth size by hemisphere. C, Boxplot showing tooth size by ocean. D, Tooth size by absolute latitude through time. E, Boxplots showing tooth size by hemisphere through time. F, Boxplots showing tooth size by oceanic region through time.Pimiento&Balk.Fig.S3Evolutionary trajectory of Carcharocles megalodon tooth size. Bars represent standard errors of the mean.Pimiento&Balk Carcharocles megalodon tooth imagesPimiento_Balk_Megalodon_Images.zip