A story out of Indiana University is likely to overturn some cherished ideas in Palaeoanthropology. Sileshi Semaw of IU has excavated the remains of a Homo erectus pelvis that came with a few surprises:
Reconstructing pelvis bone fragments from the 1.2 million-year-old adult female, Semaw and his co-workers determined the early ancestor's birth canal was more than 30 percent larger than earlier estimates based on a 1.5-million-year-old juvenile male pelvis found in Kenya. The new female fragments were discovered in the Gona Study Area in Afar, Ethiopia, in 2001 and excavation was completed in 2003.
This is contrary to what was previously thought and represents a sharp break with preceding hominids, suggesting that there was rapid evolution for larger brains and the corresponding evolution of the pelvis to accomodate them. This find is estimated to be c. 1.3 million years old.