Two-million-year-old baby jaws are reshaping what we thought we knew about early human evolution. A new study published in Nature Communications and co-authored by paleoanthropologist Dr. José Braga, introduces evidence that different early human species had distinct facial and jaw traits from infancy, suggesting that the genus Homo was already more diverse and complex than we once believed.

The research examined three rare fossilized Homo infant skull fragments, one from Ethiopia attributed to Homo habilus and two from South Africa, from a species closely related to Homo erectus. Though tiny, these fossils fragments carry big implications. They show that different human species already followed separate developmental paths from birth, rather than just shaped by environment or lifestyle as they grew older. These early differences in skeletal and dental traits point to a common ancestor to all human species that likely predates the Quaternary Period. It also indicates that our evolutionary family tree is probabaly both older and has more branches than previously understood.