A skull belonging to Australopithecus anamensis was found in Ethiopia in 2016, marking the first time the remains of this early human ancestor had been discovered. In an analysis published in the journal Nature on Wednesday of this week, researchers detailed the discovery as well as the information they were able to glean about the species and how they lived, reported CNN.
The research is part of the Woranso-Mille Paleoanthropological Research Project study in the Afar Regional State of Ethiopia and has been going on for 15 years.
Yohannes Haile-Selassie, study author and curator of physical anthropology at the Cleveland Museum of Natural History, spoke about the excitement of finding the cranium of Australopithecus anamensis.
“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.”
The skull is referred to as MRD and belongs to an early human ancestor that lived between 3.9 and 4.2 million years ago. Australopithecus anamensis is also the ancestor of Australopithecus afarensis, which lived between 3 and 3.8 million years ago and is believed to have given rise to our genus, Homo. The well-known skeleton, known as Lucy, belongs to Australopithecus afarensis and was found just 34 miles south of where researchers uncovered the MRD skull.
"Stunning ancient skull shakes up human family tree" - Article in @aaas on a recent publication including @MPI_EVA_Leipzig researcher Stephanie Melillo. #Australopithecus #evolution https://t.co/ObNzE8AYMm— MPI-EVA Leipzig (@MPI_EVA_Leipzig) August 29, 2019
Study co-author Naomi Levin, from the University of Michigan, spoke about MRD being found near a river and how anxious the researchers are to discover how the species lived.
“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.”
The skull discovery also debunks a previous theory that anamensis died off completely before giving rise to afarensis. The age of the cranium shows that the two species overlapped for at least 100,000 years. This finding also challenges the theory that human evolution occurred in a linear fashion.
Through studying and reconstructing the likely facial features of the MRD skull, researchers discovered that anamensis had a protruding face with the cheekbones projecting forward. The massive size of the jaw was also likely due to the species’ diet, which would have included hard, tough-to-chew foods.
Stephanie Melillo, study co-author and postdoctoral researcher at the Max Planck Institute for Evolutionary Anthropology, commented on how the discovery bridges the gap between the earliest-known human ancestors, which are about 6-million-years-old, and species like “Lucy,” which are only 2- to 3-million-years-old.
“One of the most exciting aspects of this discovery is how it bridges the morphological space between these two groups.”