Record of &lt;em&gt;Carcharocles megalodon&lt;/em&gt; in the Eastern Guadalquivir Basin (Upper Miocene, South Spain)

M Reolid,J M Molina

doi:10.3989/egeol.41828.342

Abstract

Tortonian diatomites of the San Felix Quarry (Porcuna), in the Eastern Guadalquivir Basin, have given isolated marine vertebrate remains that include a large shark tooth (123.96 mm from apex to the baseline of the root). The large size of the crown height (92.2 mm), the triangular shape, the broad serrated crown, the convex lingual face and flat labial face, and the robust, thick angled root determine that this specimen corresponds to Carcharocles megalodon . The symmetry with low slant shows it to be an upper anterior tooth. The total length estimated from the tooth crown height is calculated by means of different methods, and comparison is made with Carcharodon carcharias . The final inferred total length of around 11 m classifies this specimen in the upper size range of the known C. megalodon specimens. The palaeogeography of the Guadalquivir Basin close to the North Betic Strait, which connected the Atlantic Ocean to the Mediterranean Sea, favoured the interaction of the cold nutrient-rich Atlantic waters with warmer Mediterranean waters. The presence of diatomites indicates potential upwelling currents in this context, as well as high productivity favouring the presence of large vertebrates such as mysticetid whales, pinnipeds and small sharks (Isurus). These large vertebrates recorded in the Eastern Guadalquivir Basin were potential prey of C. megalodon .

Highlights

The Carcharocles megalodon is the largest macropredatory shark to have ever lived
In order to better approximate the total length of the specimen of C. megalodon from Porcuna, we considered data on crown height and crown width of upper anterior teeth from 102 specimens of C. carcharias (85 specimens) and C. megalodon (17 specimens) available in the literature (Table 1)
Note that total length from C. megalodon is calculated according to regression equation proposed by Shimada (2002)

Summary

Introduction

The fossil record of this predator is restricted to isolated teeth and vertebral centra due the cartilaginous skeleton of most of the sharks. The most complete specimen is an associated column of around 150 vertebral centra from the Miocene of the Antwerp Basin, Belgium (Leriche, 1926). The record of C. megalodon teeth ranges from 17 to 2 Ma (middle Miocene to Pleistocene) (Gottfried et al, 1996; Purdy, 1996; Pimiento et al, 2010). The largest tooth of C. megalodon measures 168 mm (specimen PF 1168, Field Museum of Natural History of Chicago)

Methods

Results

Discussion

Conclusion