In a ground-breaking archaeological finding, scientists working on the Woranso-Mille Paleoanthropological Research Project study in the Afar Regional State of Ethiopia have discovered a “remarkably complete” skull said to belong to an early pre-human that lived some 3.8 million years ago.

The discovery of the skull belonging to Australopithecus anamensis brings so much insight into the evolutionary history of mankind’s ancestors.

Researches, who has been working on the project for 15 years discovered an upper jaw of the prehistoric man on February 16, 2016. This led to a 16-hour area-wide search, uncovering dozens of other fossilized pieces of the rest of the skull.

A well detailed and comprehensive analysis of the skull and the location it was unearth has since been published in the journal Nature.

Describing his initial reaction upon unearthing the rare remains, Yohannes Haile-Selassie, study author and curator of physical anthropology at the Cleveland Museum of Natural History, had this to say: "I couldn't believe my eyes when I spotted the rest of the cranium. It was a eureka moment and a dream come true. This is one of the most significant specimens we've found so far from the site".

Referred to as MRD, the prehistoric skull symbolises the early human ancestor commonly known as Australopithecus anamensis, believed to have walked the earth between 3.9 and 4.2 million years ago. They preceded Australopithecus afarensis, to which the well-known Lucy skeleton belonged, and is believed to have given rise to our genus, Homo.

Just 34 miles north of where the Lucy skeleton were discovered in 1974, MRD was found by a team of international geologists, paleobotanists and paleoanthropologists. Its age was determined by a study of the surrounding habitat where it was found.

The skull was washed down a river after death and was buried by sedimentary soil in a delta. Scientists are of the opinion that the discovered skull likely belonged to a male and was most likely living along the river, surrounded by dense trees. The wider area farther afield was open shrubland.

According to University of Michigan lecturer and co-author on the study, Naomi Levin, "MRD lived near a large lake in a region that was dry. We're eager to conduct more work in these deposits to understand the environment of the MRD specimen, the relationship to climate change, and how it affected human evolution, if at all".

Contrary to previous belief that anamensis died off and gave rise to afarensis, the skull discovery indicated that the two species likely overlapped and lived side by side for at least 100,000 years. This is direct challenge to the established notion that human ancestors evolved in a straight linear fashion.

More Knowledge about Anamensis

Stunned by this rare discovery, the stunned researchers found themselves starring down at a face they have never seen before. They carefully cataloged the features of the skull so that it could be compared with other known human species from eastern and southern Africa.

According to Stephanie Melillo, study co-author and post-doctoral researcher at the Max Planck Institute for Evolutionary Anthropology, Australopiths were largely known for their massive physiognomy. However, an evolution towards a more modern human facial feature started with the origin of our own genus, Homo. That started when early man was using basic rudimentary tools and feeding on processed food.

Considered the oldest known member of the Australopithecus genus, anamensis is made up of a motley collection of intriguing features.  For one, it has a protruding face where the cheekbones project forward. This, scientists believe, was borne out of its need to process really tough diets and chew hard food. Thus, the facial bones evolved to withstand stress.

The braincase s long and narrow, just like those of other early human ancestors, and scientists are still trying to unravel what caused an increase in brain capacity with the genus Homo came into the scene. A likely reason, according to Haile-Selassie is that Homo used more tools, ate more meat and went around in the open more, leading to more decision-making.

A Key Evolutionary Insight

Identifying anamensis is key to allowing researchers to understand how early man evolved. Y comparing the features of the MRD skull to a 3.9million year old skull fragment that had not be assigned to any known species, the researchers are able to build a profile of what anamensis really looked like. This makes it easy to identify the Belohdelie frontal as afarensis, which belongs to the Lucy’s species. This confirms that the two species actually lived side by side for at least 100,000 years.

It’s now up for debate whether the population actually did mix up. But in the meantime, the researchers are eager to focus on learning more about how early man evolved.