Does the press release accurately reflect the study?

‘Yes, without a doubt. The press release clearly and concisely explains the finding, its chronological and environmental context, which includes climatic and ecosystem aspects in the development of Pink's life and its relevance in the general context, hence the lengthy comparison with fossils from the Atapuerca system itself and from other places in Africa and Eurasia. On the other hand, it has a markedly institutional character, highlighting the participation of leading Spanish institutions in human evolution studies (IPHES in Tarragona and CENIEH in Burgos).

Is the study of good quality? Are the conclusions backed up by solid data?

‘Of course. Fifty years ago two famous palaeontologists, David Pilbeam and Stephen Jay Gould, warned that in palaeoanthropology it is like in theology or extraterrestrial biology: there are more scholars (specialists in human evolution) than objects of study (fossils) which necessarily means that other researchers put forward alternative, different proposals. Therefore, the fact that some of the conclusions of this work may be questioned in the future does not imply that it suffers from a lack of quality. It all depends on how you look at it, on what lens we use to analyse that particular reality.

Although there are intermediate positions, when practitioners of a discipline are classified they are grouped into two factions: the lumpers (supporters of grouping) and the splitters (supporters of separation). The lumpers will always resort to arguments for not defining new species and the splitters will argue that the observable differences are due to the fact that they are different species’.

How does this work fit in with the existing evidence?

‘As for the palaeoanthropological section, it is a classic and very well executed piece of work. The comparisons with similar fossils are detailed and lead the authors of this work to a parsimonious conclusion: this is an individual very similar to the already known Homo erectus. That is why the abbreviation aff. (from the Latin affinis = akin to) is added, because it does not share all the features with that species (Homo erectus).

In my opinion it is important to emphasise that humans have been - and continue to be - tremendously variable. This diversity is due to different factors: age, sex, pathologies, living conditions, etc. And all of them are reflected in the morphology of the few fossils that we study. For this reason, and in my opinion, we must be extremely cautious when naming a new species. In this case, the authors have opted for prudence’.

Have the authors taken confounding factors into account? Are there any significant limitations?

‘There are no confounding factors. The work is very well framed and no aspect is forgotten, no fossil or important site worthy of description or comparison.

However, I would like to highlight two interesting issues:

1. The first is that during the publication process of this work an article came out about a site (Grăunceanu) in present-day Romania that raises the age of the first human settlement in Europe to almost 2 million years. This speaks to us of the dynamism of everything related to human evolution. It is a tremendously dynamic discipline (or set of disciplines). Therefore, our conclusions can be ephemeral.
2. The second has to do with the fact that this is the first face of an adult individual found in the Lower Pleistocene of Europe. The other known face, the one that appeared in Gran Dolina, and which takes on great importance in the comparative study, belonged to a girl between 9 and 11 years of age. And the child individuals have different features from the adults. Above all, if we look closely at the details. Let's hope that in the future a completely adult face will appear in the Gran Dolina or a child's in the Sima del Elefante and that individuals in the same state of development can be compared’.

What are the implications for the real world?

‘An irreverent group from Vigo, Siniestro Total, titled one of their songs ‘Who we are, where we come from, where we are going’. This shows that one of humanity's great concerns is its origin. Therefore, human evolution fascinates us because of the following paradox: we perceive our ancestors as close enough to create a bond with them and far enough away to boast about our capacity for progress.

On the other hand, we should congratulate ourselves that in Spain we have two of the best sets of archaeological sites for understanding the first human settlement in Europe: Orce and Atapuerca.

The study is obviously of high quality, but the robustness of the data is relative, due to the fact that the fossil record is always very scarce and the conclusions of the studies are never completely robust, but they are as robust as they can be until new remains are found to test the conclusions we are making.

The study is based on the results obtained, and the limitations are a consequence of the scarcity of fossils on which to compare.

The results obtained from the discovery made two years ago by Dr Rosa Huguet are highly relevant, as they allow Homo erectus to be placed on the European continent in a chronology prior to one million years ago. This is significant because, prior to this discovery, human remains found in Europe in chronologies prior to one million years ago were not completely diagnostic in terms of a precise taxonomic identification. This study therefore allows us to put a face to the hominins who inhabited the Sierra de Atapuerca over a million years ago and to know who made the stone tools and ate the animals present at the site.