Record of <em>Carcharocles megalodon</em> in the Eastern Guadalquivir Basin (Upper Miocene, South Spain)

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. Keywords: Carcharocles megalodon; fossil tooth; Guadalquivir Basin; Tortonian. RESUMENLas diatomitas tortonienses de la antigua Cantera de San Félix (Porcuna, Jaén), en el sector oriental de la Cuenca del Guadalquivir, han proporcionado restos aislados de vertebrados marinos entre los que destaca un gran diente de tiburón (123.96 mm desde el ápice hasta la línea basal de la raiz). La altura de la corona (92.2 mm), su forma triangular con bordes aserrados, la presencia de una cara lingual convexa y una labial plana, conjuntamente con la raíz angulosa y robusta, permiten determinar que este diente perteneció a un ejemplar de Carcharocles megalodon. La alta simetría de la pieza, su tamaño y su relación longitud/anchura de la corona permiten afrimar que se trata de un diente superior anterior. La longitud total estimada para este tiburón, es calculada a partir de diferentes métodos basados principalmente en la comparación con el tiburón blanco Carcharodon carcharias. La longitud total inferida finalmente para este ejemplar ronda los 11 m, lo que permite incluir este ejemplar dentro del rango de los ejemplares de C. megalodon de gran tamaño.

Ontogenetic growth pattern of the extinct megatooth shark Otodus megalodon—implications for its reproductive biology, development, and life expectancy

“…However, addressing these issues is beyond the scope of this paper primarily because our study rests on multiple assumptions, such as growth bands in IRSNB P 9893 representing annual cycles and the unconventional application of VBGF to a single individual (see Materials and Methods). In addition, the 9.21-m-TL estimate for IRSNB P 9893 (Gottfried et al 1996) and tooth-based TL estimates (Gottfried et al 1996;Shimada 2019) used in this study assume that the modern white shark is the most reasonable analogue of O. megalodon among modern sharks (Randall 1973;Gottfried et al 1996;Reolid and Molina 2015;Razak and Kocsis 2018;Shimada 2019). Nonetheless, our study is the first of its kind for the iconic species, taking the science of O. megalodon one step further.…”

Body, jaw, and dentition lengths of macrophagous lamniform sharks, and body size evolution in Lamniformes with special reference to ‘off-the-scale’ gigantism of the megatooth shark, Otodus megalodon

“…Because teeth of C. carcharias are considered to be the best modern analogue to estimate the gigantic size of the extinct megatooth shark, Otodus megalodon (e.g. Gottfried et al 1996;Shimada 2003;Reolid and Molina 2015;D'Anastasio et al 2018), we added the TL and essential tooth measurements (CH of A1 and a2) from a 'midsized' (ca. 3.8 m TL) individual as well as from the largest (ca.…”

Body length estimation of Neogene macrophagous lamniform sharks (Carcharodon and Otodus) derived from associated fossil dentitions

“…Carcharodon carcharias is the largest macrophagous shark alive today, achieving maximum body lengths of arguably 6 to 7 m (Gottfried et al, 1996;Castro, 2012;McClain et al, 2015). Otodus megalodon represents the largest macrophagous shark that ever lived, with contentious adult estimates ranging from 10 to more than 30 m (Dean, 1909;Randall, 1973;Bendix-Almgreen, 1983;Gottfried et al, 1996;Pimiento et al, 2010;Pimiento and Balk, 2015;Reolid and Molina, 2015;Trif et al, 2016;Grant et al, 2017;Razak and Kocsis, 2018;Shimada, 2002aShimada, , 2019Herraiz et al, 2020). This longstanding interest in body size of the world's largest marine macropredators has been shared by professional paleontologists and the public alike.…”