Experts question hominoid origin of 9.7-million-year-old teeth from Germany

To the scientists who found the teeth, they looked apelike or even human – but others disagree.

When Herbert Lutz, deputy director of the Natural History Museum in Mainz, Germany published a preprint about his discovery at the end of October, it made waves in media worldwide (see our interview with him here). In this paper, he described what would have been a sensation: two teeth found in Eppelsheim, Germany, possibly of hominoid origin, 9.7 million-years-old, and predating comparable finds from Africa by four to five million years. In a press conference, the city’s mayor even speculated that these findings might require the history of mankind to be rewritten.

But these speculations were shot down fast. Just two days after the revelatory paper was uploaded as a preprint to ResearchGate, two experts with experience in primate dental anatomy commented on Lutz’s paper and challenged his findings. To them, the teeth didn’t look human or apelike. Rather, they suggested, one tooth could have belonged to a long extinct ungulate, and the other to a primitive primate that has no direct ties to human evolution.

Supposed molar (left) and canine (right) fossils found in Germany raise questions about human history. Image: Naturhistorisches Museum Mainz

This is far from what Lutz had suggested in his paper. He had written that both teeth came from one body, and that at least one tooth, which he had described as a canine, showed hominin characteristics. In a section of his paper that compares the teeth’s morphology to other species, however, Lutz admits that the molar shares characteristics with pliopithecoids. These primitive catarrhines were widespread in Eurasia and lived before old world monkeys and apes diverged.

Monte McCrossin, one of the commenters on Lutz’s paper, backs this pliopithecoid theory. More precisely, he believes that the molar belonged to an Anapithecus, a primitive primate that’s also known from fossils found in Hungary and elsewhere in Europe. McCrossin works at the department of anthropology at New Mexico State University and has been part of multiple digs and projects on ape evolution in the past 30 years.

A pliopithecoid molar would also verify the origin of another discovery, a thigh bone that was found in Eppelsheim in 1820, and is believed to belong to the species. McCrossin’s comment on the preprint concludes, “Sadly, this discovery isn't at all what it claims to be; it's fool's gold.”

As for the second tooth, McCrossin believes that the canine described in Lutz’s paper is neither a canine, nor hominoid. He thinks it most closely resembles a a fragmented molar that once belonged to a long extinct ungulate; a large, hoofed mammal. Jay Kelley at the Institute of Human Origins at Arizona State University, the other commenter on Lutz’s paper, agrees. He believes that Lutz's supposed canine appears to have been a broken molar, rolled or digested, resulting in the rounding of all its broken edges and making it easy to confuse. Kelley was part of another team who identified a nine-million-year old pliopithecoid in India earlier this year.

McCrossin believes the supposed canine most likely is a broken molar from a Dorcatherium, an extinct deer-like creature that lived during the Miocene. Image: Wikipedia

McCrossin and Kelley are just two voices in a conversation across anthropology departments and Natural History museums around the world, from Sofia, Bulgaria to Toronto, Canada and Frankfurt, Germany. All experts agree with the two commenters on the non-hominoid origin of the teeth.

So how could this happen? Lutz himself has written many papers about fossilized insects, but not specifically about monkeys. Critics point out that Lutz didn’t consult a specialist on monkey teeth before he spoke with the media. One of the specialists that Lutz lists in his paper’s acknowledgement section is Ottmar Kullmer. But Kullmer, who focuses on the evolution and function of teeth and bones in mammals at the Senckenberg Museum in Frankfurt, Germany, also only learned about the results after they were published. In fact, he didn’t know that he was listed in the acknowledgements before we inquired. He had participated in the dig in the early 2000s but says he hasn’t been involved in the project since.

Kullmer regrets that Lutz didn’t speak with him or another dental anatomist earlier. He also admits that it can be tricky to be 100 percent sure about the origin of these million-year-old fossilized teeth: “We make huge scientific efforts to do research in a field that – in the end – is historical, because it’s about reconstructing something that’s long gone. It’s all about the details, and there are specialists who have been dealing with these details for decades. They can tell apart the many different monkey species.”

Perhaps Lutz didn’t ask his peers prior to publication because he was afraid that they could steal the show. In a story by the German newswire Deutsche Presse Agentur, Lutz mentioned that he didn’t want to just be mentioned in the fine print. He wanted it to be clear who made the discovery – also for the politicians in the provincial government, who he adds, invested 800.000 Euros into the dig over the past few years. He didn’t want them to question what the scientists had been up to all that time.

Maybe Lutz also wasn’t aware of his options. He published his findings as a preprint – a draft that’s handed into a journal but hasn’t gone through the normal peer-review process yet, where the text is sent other scientists to check it. He could have, however, uploaded a preprint to a preprint server, or to ResearchGate as he did, and asked for feedback from peers himself, prior to going to the media and having his results distributed widely.

“There’s increasing pressure to publish results,” Kullmer says and warns that this pressure could lead to howlers like this. He thinks this is a risky development. “As a scientist you then have to ask yourself: will I still be able to sleep at night if I publish this?”

Lutz himself hasn’t responded upon inquiry. A press officer at the provincial capital city of Mainz, speaking on behalf of the Natural History Museum and Lutz, confirmed that Lutz and his team are taking the other scientists’ criticism seriously, and that more topic experts will be consulted as the process of ascertaining the teeth’s origin continues.

Kullmer and the other experts wish this had happened much sooner.

Feature image: Naturhistorisches Museum Mainz.