Findings about the arrival of human ancestors in Europe are under a cloud following allegations of theft and dubious record-keeping at a prominent fossil site in Germany.
The Untermassfeld site, about 150 kilometres north of Frankfurt in Germany, is well known as a repository of non-human animal fossil remains. Since excavations began in the 1970s, palaeontologists have so far recovered fossils of more than 14,000 large animals, dating from between 900,000 and 1.2 million years ago.
The animal remains are uncontroversial and their dating is robustly supported. However, in 2013, a paper was published in the journal Quaternary International suggested that rocks found at the site were possibly stone tools.
The lead authors of the paper were Günter Landeck at the North Hessian Society of Prehistory and Archaeology of the Medieval in Bad Hersfeld, Germany, and Joan Garcia Garriga of the Universitat Oberta de Catalunya in Spain.
In 2016, the pair again collaborated for a paper in the Journal of Human Evolution that suggested that marks on animal bones found at Untermassfeld were made by hominin cutting tools. This year, they returned to the subject in a new paper for Quaternary International.
The implication of all three papers was highly significant. Most existing hominin fossil evidence suggests that hominins reached southern Europe around one million years ago, but did not travel north into the centre of the continent until about 350,000 years ago.
Their presence at Untermassfeld at the same time as the animal fossils clearly throws the orthodox timeline into disarray.
But the findings of Landeck and Garcia Garriga have now been strongly challenged by a team of archaeologists led by Wil Roebroeks at Leiden University in the Netherlands.
Taking the highly unusual step of posting a detailed letter on the biology preprint platform bioRxiv, Roebroeks and colleagues cry foul, alleging that some animal bones used in the hominid analysis may have been stolen and others may not have come from the site at all.
Looking at the findings made in the three papers, the new team conclude that “these studies are severely flawed in terms of data on provenance of the materials studied”. They go further, suggesting that “any reference to the Untermassfeld site as an archaeological one is unwarranted”.
In posting their letter on the preprint server Roebroeks and colleagues have garnered immediate attention. The story has recently been covered in the journal Nature, and the two journals in which the original Landeck and Garcia Garriga papers were published have issued statements of concern regarding them – a significant step towards formal retraction.
While Roebroeks’ team does not allege wrongdoing on the part of Landeck and Garcia Garriga, there is the suggestion that questions regarding the provenance of the artefacts and bones used in their analysis were not asked with sufficient rigour.
The bioRxiv paper suggests that at least some of the bones and rocks used in the studies may not have come from the Untermassfeld site.
Landeck and Garcia Garriga state that the bones came from “the Schleusingen collection” – a privately held stash collected in the 1970s and 80s by an amateur palaeontologist.
One of Roebroeks’ co-authors, palaeontologist Ralf-Dietrich Kahlke from the Senckenberg Research Station of Quaternary Palaeontology in Weimar, Germany, told Nature that he had never heard of such a collection, and doubted that, if it existed, it would contain Untermassfeld material.
The excavation of the site, he said, began in 1978 and professional access has been tightly controlled ever since. However, he added, there have been multiple instances of theft, which he had reported to the police.
One of the bones, from a deer’s leg, used by Landeck and Garcia Garriga to support their contention of hominin occupation was part of a package of fossils and rocks sent anonymously to the Untermassfeld Museum. Roebroeks and Kahlke suggest that the bone closely resembles one stolen from the site.
They also suggest that another bone used in the analysis – this one from a rhino – was also previously stolen.
They add that the present location of some of the material used in the Landeck and Garcia Garriga papers is unknown, so independent testing has not been possible. Marks on other bones, they claim, are evidence of rodent, not hominin, activity.