First occurrence of the giant shark Carcharocles megalodon (Agassiz, 1843) (Lamniformes; Otodontidae) at Buenos Aires Province, Argentina

Julieta De Pasqua,Diego Gambetta,Alexis M. Aranciaga Rolando,Sergio Bogan,Federico Agnolin

doi:10.4072/rbp.2021.2.05

Abstract

Carcharocles megalodon is considered a macropredatory shark that inhabited the seas around the world from middle Miocene to late Pliocene. In Argentina, it has only been formally recorded at two localities. Here, we report the first record for this taxon in the Buenos Aires Province. This occurrence is based on an isolated tooth recovered on the beach at the Punta Médanos locality, which lacks clear stratigraphic context. Based on the regional geology, the specimen probably came from Pliocene beds. Its size indicates that it probably belongs to a juvenile individual. Keywords: Carcharocles megalodon, macropredatory shark, fossil teeth, Mar de Ajó.

Highlights

Carcharocles megalodon (Agassiz, 1843) is considered a macropredatory shark that inhabited warm marine waters all around the world from the middle Miocene to late Pliocene (Applegate & Espinosa-Arrubarrena, 1996; Gottfried et al, 1996; Purdy, 1996; Pimiento et al, 2010; 2013; 2016; Cappetta, 2012; Pimiento & Clemens, 2014; Boessenecker et al, 2019)
In spite of marine abrasion, the specimen MMDA-101 is confidently identified as Carcharocles megalodon on the basis of the following combination of characters: relatively large crowns which are subtriangular in contour, with a convex lingual surface and a nearly flat labial surface, presence of a chevron-shaped band on the lingual surface separating the root from the crown, poorly developed lingual protuberance of roots, and well-differentiated root lobes separated by a shallow basal concavity (Gottfried et al, 1996; Pimiento et al, 2010; Cappetta, 2012; Cione et al, 2012; Medina-Gavilán et al, 2015; Boessenecker, 2016; Viciano et al, 2018)
The crown width (CW) and Crown height (CH) of MMDA-101 fall within the morphological cloud of C. megalodon carried out by Pimiento et al (2010) (Figure 3A)

Summary

Introduction

Carcharocles megalodon (Agassiz, 1843) is considered a macropredatory shark that inhabited warm marine waters all around the world from the middle Miocene to late Pliocene (Applegate & Espinosa-Arrubarrena, 1996; Gottfried et al, 1996; Purdy, 1996; Pimiento et al, 2010; 2013; 2016; Cappetta, 2012; Pimiento & Clemens, 2014; Boessenecker et al, 2019). As is the case of most Neogene sharks, its fossil record is restricted to isolated teeth and vertebral centra (Gottfried et al, 1996; Reolid & Molina, 2015). Several fossiliferous deposits around the world yield teeth of Carcharocles megalodon and, for this reason, it is currently considered that this species had a global geographical distribution (Uyeno et al, 1989; Purdy et al, 2001; Reolid & Molina, 2015; Pimiento et al, 2016). The goal of this study is to document the first record of C. megalodon from the Buenos Aires Province, discuss the stratigraphy of the area it was found in, and calculate the total length and body mass of the shark the tooth came from

Objectives

Methods

Conclusion