Human Species Mystery

Scientists believe a 300,000-year-old fossilized jawbone found in a cave in eastern China might belong to an unidentified species of ancient humans. The recently published findings show the mandible—the lower part of the jaw—has both modern and archaic anatomical features, prompting questions about a possible new branch of the human family tree.

Scientists from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing excavated the cave in China's Anhui province and discovered the remains of 16 individuals as well as fragments of the skull of a 12- to 13-year-old juvenile. They eventually pieced together fragments of a mandible belonging to the same skull.

They found the mandible's thick jawline is a feature shared with early human species, such as Homo erectus, while the lack of a prominent chin is a feature shared with Homo sapiens. However, the Homo sapiens-like features of the mandible differ from those of other hominins from the Middle Pleistocene, from around 126,000 to 800,000 years ago, which palaeoanthropologists say could represent a previously unknown ancestor of early Homo sapiens.