Excavations in the region of Gona, Ethiopia, unearthed the first and almost complete pelvic fossil belonging to a Homo erectus female who lived 1.2 million years ago. The discovery is of extreme importance in establishing a new element in the evolutionary chain of the human brain.

Paleontologist Scott Simpson, from the Case Western Reserve University School of Medicine, lead author of the study to appear in the journal Science, made comparisons with the Australopithecus afarensis specimen known as Lucy, which is about 2 million years older than the H. erectus female, and discovered that the pelvis evolved toward delivering offspring with larger brains.

Up until this point, the information scientists had on hominids living in the Pleistocene era were based on the 1.53 million year old Turkana boy. Prior data suggested that the evolution of the pelvis was connected to endurance in an arid environment. However now, it appears to have been connected to adaptation to birth. Furthermore, the H. erectus female, who was approximately 4.5 feet tall - the Turkana boy was 6 feet tall - had a diamond-shaped body.

Simpson explained that the brain of the H. erectus was probably somewhere around 315 cubic centimeters at birth, compared to approximately 380 for newly-born babies in modern humans. “H. erectus had one foot in the past and another foot in the future,” he said.

The pelvis was dug out from crumbling and eroding soil, in a swamp area located close to a permanent river. The female was in her 20s, researchers said, and is believed to have given birth shortly before death. The cause of death has not been established, but the scientists excluded the possibility of being attacked by a carnivore. Since the burial of the dead was not practiced, the H. erectus female probably died in a sudden flood.

Simpson said he will return to the digging site in the coming weeks for two months of field work, hoping to find other skeletal material from the same period.