Ancient Ethiopian Teeth Reveal New Human Ancestor Species

A groundbreaking discovery in Ethiopia has unearthed fossilized teeth belonging to a previously unknown species within the human evolutionary tree, offering fresh insights into a pivotal era of our ancestry. The findings, detailed in this week’s issue of Nature, reveal the remains of two individuals representing a seventh known species of Australopithecus, an early hominin group exhibiting a blend of ape-like and human characteristics.

The fossils were recovered from the Ledi-Geraru region of Ethiopia’s Afar Region, dating back approximately 2.65 million years. Researchers identified ten teeth – including molars, incisors, a premolar, and a canine – that definitively distinguished them as belonging to this novel Australopithecus species. Remarkably, these fossils were unearthed in the same area and timeframe as evidence of the earliest recognized member of the genus Homo, the lineage to which modern humans (Homo sapiens) belong.

While names have yet to be assigned to either the new Australopithecus or Homo species due to the fragmentary nature of the finds, the research sheds light on a period of human evolution that has remained largely obscure. The close chronological proximity suggests these two distinct hominin groups coexisted, prompting questions about potential competition for resources in their shared environment.

The discovery pushes the known number of contemporaneous hominins inhabiting East Africa at the time to four. Alongside the newly identified Australopithecus and early Homo, fossils indicate the presence of another Australopithecus species and a Paranthropus species—characterized by specialized skulls adapted for robust chewing—inhabited this region. A separate Australopithecus species also lived in southern Africa, bringing the total number of hominin species on the continent to five at that time.

“This underscores the complexity of human evolution,” explained Brian Villmoare, a paleoanthropologist at the University of Nevada, Las Vegas and lead author of the study. “Rather than a linear progression, our ancestry appears marked by repeated branching events, with multiple hominin species coexisting throughout history.”

Researchers are now focusing on analyzing dental wear patterns to ascertain if there was dietary overlap between the two species, which could have fueled interspecies conflict. Previous discoveries of rudimentary stone tools in the area – likely crafted by the early Homo—further reinforce this possibility. The age of the teeth was determined using radiometric dating techniques applied to feldspar crystals within volcanic ash layers surrounding the fossil finds.

The Afar Region, once a lush landscape supporting diverse fauna including giraffes, horses, pigs, elephants, hippos, and antelopes, now presents a starkly arid environment. Nevertheless, it continues to yield crucial evidence illuminating the intricate tapestry of human origins.