A little over a year ago, we reported a vast expanse at the foot of Asperillo Rock, on the edge of the Doñana Natural Area in Huelva, Spain. There, in addition to numerous animal tracks, others were found – humanoid tracks.

Until then, the only time reference that allowed us to determine the age of the site was that one of the dunes covering the surface was dated to about 106,000 years ago (Upper Pleistocene). As with most hominid tracks found around the world, we have dated them according to their environment. Therefore, our initial hypothesis when trying to explain the newly found footprints was that they belonged to Neanderthals living in the Upper Pleistocene.

However, during our research, we sampled the surface where the footprints had never been dated before and the dunes on them. It turned out to be about 295,800 years old (Middle Pleistocene): much earlier than previously thought.

Sudden climate change

The new dating placed the footprints in a new geographical and ecological context. 300,000 years ago, the continent of Europe had to undergo a drastic climate change. The relatively warm conditions have been replaced by much colder conditions that heralded the Ice Age. At that time, sea levels on the European continent averaged 60 meters below modern levels, meaning that Huelva’s coastline must have been 20 to 25 kilometers off its current location.

In other words, the coastal plain was very extensive and probably consisted of a river delta. It was probably covered by water during the rainy seasons and fully or partially exposed during the dry seasons. Hominid and other fauna trampled this shallow and salty lake environment consisting of polygonal soils and microbial mantles. Today, the same type of polygonal cover can be found in large marshy areas in both hot desert and tropical climates.

More or less large areas of vegetation can be found in the non-flooded areas of this vast coastal plain. There will be significant development of dune systems moving inward from the shore around them. An overview of the Matalascanas coastal area of ​​Huelva and the humanoid traces discovered there. Credits: E. Mayoral, provided by the author

New suspects?

Environmental context and landscape changed from first comment. Therefore, the question arose whether our understanding of who made these marks would change. The answer can be found in the paleontological annals.

Humanoid fossils from the Middle Pleistocene are believed to belong to the Neanderthal genus: Homo neanderthalensis and Homo heidelbergensis. However, its remains are still scarce, fragmented and geographically dispersed. Worse still, footprints are even rarer than skeletal remains. In all of Europe during the Middle Pleistocene, only four sites provided traces of this period: Terra Amata, France (380,000 years), Roccamonfina, Italy (345,000 years, attributed to Homo heidelbergensis), Biache-Vaast, France (236,000 years, Homo neanderthalensis ) and Theopetra in Greece (130,000 years, Homo neanderthalensis).

On the other hand, it should be noted that the formal features of the footprint are the result of not only the anatomy of the foot, but also other factors such as biomechanical properties, type of substrate, and processes that lead to the footprint. fossil. Therefore, fingerprints examined should be well preserved and show various anatomical features (finger arch print) that are rare at sites such as this Huelva site.

To confirm which hominid group the tracks belong to, we will need to compare their anatomical features with known skeletal data from the Middle Pleistocene. Almost all known leg fossils from this period come from the Cima de Los Huesos region (Atapuerca, Spain) and are associated with individuals related to Neanderthals. A more precise attribution would be difficult as there is much debate about the evolution of this lineage and the taxonomic definition of Homo heidelbergensis.

Various models of Neanderthal evolution have been proposed, but the question is still far from being resolved, given the paucity of the fossil record and the new and more complex evolutionary picture provided by recent studies of ancient DNA. In addition, not all anatomical features developed at the same rate, and polymorphism likely occurred at different rates of appearance in different features.

Despite these uncertainties, the Doñan site appears to be a crucial record for understanding human activity in Europe during the Pleistocene. Our recent acquaintances open up a wider horizon of possibilities. For example, we can look at the remains of very early Neanderthal hominids or their more recent ancestor Homo heidelbergensis.