The research, led by the Professor of Paleontology at the University of Huelva, Eduardo Mayoral, was published by Scientific Reports, one of the publications of the Nature group, on 19 October.
Optically-stimulated luminescence is a method used to find the absolute age of sediments that have been fully exposed to sunlight.
The discovery in June 2020 of hominin footprints more than 106,000 years old next to El Asperillo (Matalascañas, Huelva) was a revolution for the scientific world, so much so that it was considered one of the most important discoveries of that year. But now, the publication of this new paper has confirmed what some experts suspected at the time: those footprints were much older and are in fact 200,000 years older than previously thought. While it was previously placed in the Upper Pleistocene, the evidence now points clearly to the Middle Pleistocene, and to its being 295,800 years old, making it a unique record in Europe, since there is no better site in the world in terms of number, age and area than that of the El Asperillo beach for hominin fossil footprints.
After collecting samples from the various levels, and another two later to compare the first results, the age of the fossil remains was established and points to the Middle Pleistocene, a crucial moment between different climatic stages, between a warm period, MIS 9 (360,000-300,000 years ago), in transition to MIS 8 (300,000-240,000 years ago), in which a major glaciation took place.
The age is thus specified at 295,800 years, with a margin of error of 17,800 years, according to the data collected from the four samples of sedimentary levels in the cliffs of El Asperillo where the site was found, initially 87 footprints, which now has a record of more than 300 footprints, of which 10% are considered well-preserved. With the exception of those from Matalascañas, it is noted that no other hominin footprints are known between the climatic stages MIS9 and MIS 8 of the Middle Pleistocene. That is why it is questioned whether they belong to Neanderthals.
But are they Neanderthals?
At first they were thought to be Neanderthals, but that is now in doubt. The main hypothesis among the scientists is that they are individuals of the Neanderthal lineage, among which Homo heidelbergensis and Homo neanderthalensis have been associated. The hypothesis that they are pre-neanderthal hominins is feasible. Precisely for this reason, the Matalascañas footprints are now more valuable due to their contribution to the fossil records of hominins in the Middle Pleistocene, which is very poor in Europe because of the scarcity of deposits with footprints. Until now, according to the Nature paper, footprints this period have only been found at Terra Amata and Roccamonfina (Italy), which were dated to between 380,000 and 345,000 years ago, with records of Homo heidelbergensis. They are the only ones older than that at Huelva in this era. After these, Biache-Vaast (France) and Theopetra (Greece) sites, from 236,000 to 130,000 years ago, are attributed to Homo neanderthalensis. In this context, the length range of all the footprints found at Matalascañas, from 14 to 29 centimetres, is similar to that found at European sites, such as Theopetra (14-15 centimetres), Roccamonfina (24-27 cm) and Terra Amata (24 cm).
In any case, the experts highlight the singularity of the Matalascañas discovery, whose new dating has questioned the existing paradigms and has required a deep analysis before accepting its conclusions.
The new chronology now establishes a change in the scenario that then prevailed on the coast of the Gulf of Cádiz, with human settlements in a more temperate and humid climate than in the rest of Europe, with high water tables and abundant vegetation.
In that same period the sea level would have been about 60 metres below its current level. This implies that the coast would be more than 20 kilometres from where it is today, which is how there would have been a great coastal plain, with large flood-prone areas, in which the footprints discovered in mid-2020 would have been made.
The site’s new dating also affects the vertebrate animals found, since the hominin traces there also included footprints of large mammals such as straight-tusked elephants, gigantic bulls (aurochs) and boars. It was the fauna that inhabited Doñana 300,000 years ago and not 100,000 years ago, as other investigations stated.
The paper, New dating of the Matalascañas footprints provides new evidence of the Middle Pleistocene (MIS 9-8) hominin paleoecology in southern Europe, is the result of the work of an international team of scientists led by the Professor of Paleontology at the University of Huelva, Eduardo Mayoral, alongside the lecturer Antonio Rodríguez and Professor of Stratigraphy Juan Antonio Morales, all of the Department of Earth Sciences of the Faculty of Experimental Sciences, who are also members of the Centre for Scientific and Technological Research (CCTH) at UHU, as well as Jérémy Duvau, a researcher at the Museum National d’Histoire Naturelle (France); Ana Santos, from the University of Oviedo; Ricardo Díez-Delgado, from the Doñana-CSIC Biological Station; Jorge Rivera, from the University of Seville; Asier Gómez-Olivencia, from the University of the Basque Country; and Ignacio Díaz, from the University of Río Negro (Argentina).