A publication of the Archaeological Institute of America
A one-million-year-old skull bearing traits associated with both Homo erectus and Homo sapiens has been found in the Afar region of Eritrea, pushing back the development of modern human morphology by some 300,000 years. Excavated between 1995 and 1997 by Ernesto Abbate of the Università di Firenze (Florence, Italy) and an international team of paleoanthropologists, the nearly complete cranium of an adult, along with two pelvic fragments and two incisors, was recovered from ancient lake and river sediments deposited within the primarily volcanic Northern Danakil Formation.
According to Abbate and his team, the skull's long ovoid braincase, wide cheekbones, and massive browridge resemble African H. erectus and H. ergaster. The cranium is widest (measured side to side) relatively high on the vault, clearly a modern trait. The skull, which has yet to be fully analyzed, has an estimated cranial capacity of 750 to 800 cubic centimeters.
Until this discovery the earliest known fossils bearing comparatively modern human traits were those of a 600,000-year-old H. heidelbergensis from Bodo, Ethiopia (see "A New Species?," September/October 1997). Exactly when the transition from H. erectus to archaic H. sapiens occurred has been the subject of much debate with scholars proposing several plausible scenarios, all of which depend on species classification. Given the date of the skull between 1.4 to 0.6 million years ago, a period for which few cranial specimens exist, the discovery is sure to shed light on a time poorly understood in the paleontological record. The bone-bearing layers also included the remains of hippopotamus, rhinoceros, horse, hyena, and crocodile. The fossils were dated by paleomagnetic dating--a method by which the age of deposits can be determined by the magnetic orientation of particles in the surrounding volcanic tuffs in relation to Earth's magnetic field.