A jawbone that is 2.6 million years old alters the course of human history.

Scientists' mapping of the early human family is changing as a result of a recently discovered Paranthropus jawbone fossil. In the Afar area of Ethiopia, researchers discovered a partial lower jaw, which they dated to roughly 2.6 million years ago.

The discovery suggests that Paranthropus was far more mobile and adaptive than previously thought, pushing the genus' known range more than 600 miles north.

Paranthropus was present in Afar during a crucial period of early human evolution, according to study headed by Dr. Zeresenay Alemseged of the University of Chicago. Its absence from the area currently seems to represent gaps in the fossil record rather than a real border.

Long-held beliefs about the locations of early human cousins and their responses to shifting environments are called into question by this local discovery, which connects to more general environmental and evolutionary patterns.

Locating the relative who went missing

Extremely large molars and a strong chewing mechanism are characteristics of the extinct Paranthropus branch of the human family. The fossil, which is thought to be around 2.6 million years old, adds nearly 620 miles to the species' known range to the north.

Although many fossils from other lineages had been found in Afar, Paranthropus had never been found there, at least not in collections that were known to exist. Claims that the genus remained farther south due to weak competition or dietary restrictions were fuelled by that empty region.

The pieces originated from the Mille-Logya study area, where a unique window of deep time is preserved by sediments. On January 19, 2019, field workers discovered fragments of the lower jaw and screened the ground to find more.

The delicate pieces were carefully transported to Addis Ababa, where museum staff safeguarded them, according to permissions from Ethiopian cultural officials. Each new bone can anchor a time that was previously absent since the basin contains layers that span several million years.

Diet is shown by the Paranthropus jaw

Researchers can see inside the fossil, all the way down to the roots that previously held hefty teeth in place, thanks to high-resolution X-ray images. These interior geometries made it possible for software to recreate the jaw in detail without harming the delicate pieces because dense bone blocks X-rays.

Even though the specimen lacked enough markers to be definitively assigned to a single species, comparisons with other fossils revealed a broad, robust jaw body and massive molar roots—traits associated with powerful chewing forces.

Large muscular attachment locations around the cheek and jaw would have boosted bite force by pushing harder on bone, whereas those big roots indicate substantial chewing loads during daily meals. But as seen by the pitting and scratches on Paranthropus teeth, meals were not always constructed around hard items.

The Afar jaw cannot be interpreted as evidence of a highly specialised eater because the architecture and wear patterns together point to a robust yet adaptable feeding system.

Chemical traces

Chemical traces locked in tooth enamel offered another angle on what Paranthropus ate across different habitats. Long after death, food retains chemical traces. The scientists looked at stable isotopes and minute variations in carbon atoms.

Although the jaws appeared to be designed for hard materials, carbon analysis of Paranthropus teeth clearly suggested grass and sedge diets. The assumption that the genus was not restricted to a particular food source is supported by this wider diet, which is consistent with the Afar fossil.

Additionally, the site's evidence put the jaw in a region where early Homo, the genus that includes humans, had already visited. Overlap is important because local conditions might favour certain features over others and shared habitats can lead to competition.

Alemseged stated, "We must comprehend the environmental, ecological, and competitive factors that shaped our evolution if we are to understand our own evolutionary trajectory as a genus and species."

The new discovery transforms competition from a straightforward narrative into a testable inquiry that requires further fossils.

The fossil record's gaps

Whole areas may appear uninhabited since fossils only show up after bodies are buried, conserved, and then uncovered once again. What survives is determined by erosion, river cuttings, and tiny search areas, which can conceal a species for decades.

Old explanations can fall apart in a season when a discovery bridges the divide, leaving new questions in their wake. It also implies that new findings may disprove existing maps, particularly in areas that have not yet been thoroughly investigated.

Human history and the Paranthropus jaw

The first stages of numerous human lineages can be traced back to the critical period between three and 2.5 million years ago. It took place during a time of fluctuating vegetation and rainfall, which altered the nutrients that were accessible and would have rewarded new bodies and behaviours.

However, there aren't many well-dated fossils from this era, so scientists must reconstruct family trees from fragments and argue over the number of relatives that lived in the same area.

A tougher, more mobile Paranthropus coexisting with early humans is suggested by the new jaw, its thorough scans, and previous dietary findings.

When taken as a whole, they highlight the significance of eastern Africa, where the majority of human origins myths are still anchored by a small number of places.

In order to verify long-held theories and create a more comprehensive, trustworthy map of early human variety, scientists now require additional fossils from these crucial levels in order to advance past those anchors.