Prehistoric Fossil Teeth Spark Heated Debate Over Human Evolution

Different views of an upper right molar tooth excavated near Eppelsheim, Germany

In a paper shared at the social networking site ResearchGate, Herbert Lutz and his team say they discovered “a new great ape with startling resemblances to African members of the hominin tribe.” The "plausible age” of the fossils — an upper left canine tooth and an upper right first molar — is 9.7 million years, they say.

If confirmed, that would make the teeth around 6 million years older than fossils for the early human African ancestor Australopithecus afarensis, aka Lucy, and emerged over 9 million years before anatomically modern humans were thought to have migrated out of Africa.

The fossil teeth potentially provide evidence that a human lineage evolved outside of Africa, and before major African human lineages first emerged.

Michael Ebling, the mayor of Mainz, added to the intrigue by telling the German media site Merkurist, “I would suggest that we must start rewriting the history of mankind after today.” 

Co-author Axel von Berg, an archaeologist in the state of Rhineland-Palatinate, echoed the excitement when he told Allgemeine Zeitung, “This will amaze experts.”

Lutz, von Berg, and their colleagues report that the teeth exhibit characteristics similar, not only to Lucy, but also to other early hominins such as Ardipithecus ramidus and Ardipithecus kadabba. They estimate that the teeth belonged to an individual who weighed about 33 pounds. In contrast, Lucy is thought to have weighed between 45–110 pounds.

The site where the teeth were unearthed, Germany’s Eppelsheim formation, has previously yielded other important fossils. A femur excavated there in the early 19th century is believed by many to be the world’s first known primate fossil. Excavations between 1934 and 1935 that were directed by scientist Otto Schmidtgen unearthed still more primate fossils with hominoid features. These fossils, all teeth, were somehow lost during World War II, however.

The newly unearthed teeth were found at practically the same spot after 20 years of “painstaking excavations,” the researchers write, adding that, “Both teeth represent a hitherto unknown great ape with startling hominin resemblances.”

The teeth differ from all other known human ancestral remains found in Europe and Asia so far, according to the researchers. The date of the fossils was determined by the geological layer within which they were found and by surrounding microfossils. Radiometric or other more precise methods of dating have not yet been conducted.

Artist’s reconstruction of the face of Australopithecus afarensis

Despite the lofty claims about the teeth, human evolution experts have been largely underwhelmed by the new discovery.

“The possible findings of more evidence of hominids outside of Africa is interesting, especially for deep hominin history, but I don’t think the overall picture of hominid evolution will change much,” Carina Schlebusch, an assistant professor in the Department of Organismal Biology at Uppsala University, told Seeker. “Genetics still point to a relatively recent African origin of the variation in all living humans.”

Anthropologist Monte McCrossin of New Mexico State University offered even more harsh words.

“Sadly, this discovery isn’t at all what it claims to be; it’s fool’s gold,” he wrote in a comment posted on ResearchGate. “This site in Germany has nothing whatsoever to do with human evolution.”

Paleoanthropologist David Begun of the University of Toronto and other scientists suspect that one or more of the fossils found at Eppelsheim could have belonged to a genus of extinct primates known as Pliopithecus, and not hominids.

Skull of the fossil primate Epipliopithecus vindobonensis on display at the Field Museum of Natural History

Begun told Seeker that he and his colleagues theorize that the African ape and human lineages arose from a European or Western Asian ancestor that migrated to Africa about 7–9 million years ago. Some human ancestors are then thought to have migrated back to Europe and Asia, while others continued to evolve in Africa.

The complex back and forth migrations might at first seem “unnecessarily complicated,” he said, but he said similar theories help to explain the evolution of other animals, such as aardvarks and hippos.

Evidence for possible early human presence outside of Africa also goes beyond debates over the Eppelsheim teeth.

In August, it was reported that fossil footprints possibly belonging to a hominin were found on the island of Crete. They date to 5.7 million years ago. According to the authors of the paper, published in the Proceedings of the Geologists’ Association, the individual who left the prints was bipedal, walked on the soles of its feet, and exhibited other human-like characteristics.

This year, it was also reported that a human-resembling primate, Graecopithecus freybergi, lived in the Eastern Mediterranean around 7.2 million years ago. Madelaine Böhme of the Senckengberg Center for Human Evolution and Paleoenvironment at the University of Tübingen, Begun, and their team analyzed fossils for the primate, nicknamed El Graeco.

The oldest higher primates are known from Asia more than 40 million years ago,” Böhme told Seeker. “But hominids have surely evolved from African hominids. After 14 million years, they first enter Eurasia and diversified into Ponginae — orangutan — and Homininae.”

It is possible that the Eppelsheim individual descended from one of these early migrations. On the other hand, it could belong to a lineage that remained in Asia and Europe.

Various views of the upper left canine tooth found at Eppelsheim

While experts debated the many possibilities, Lutz’s voice and that of his team was notably absent.

“Our paper provoked contradiction, which we take very seriously,” Lutz told Seeker. “We will now first reexamine the finds to see which of the proposed relationships is the most plausible one.”

Relationships refers to how the teeth should be classified.

“Under these circumstances,” he added, “we want to postpone any further comment until we have cleared the situation.”

The initial controversy over the Eppelsheim discovery has fizzled out — for now. But it’s clear that many important questions remain about human evolution, which could significantly impact our lives.

Differences in genetics, for example, can affect medical treatments. Neanderthal heritage, for example, can influence a person’s appearance, behavior, health, and even habits, such as smoking.

Read more at Seeker