New clues from two million-year-old tooth enamel tell us more about an ancient relative of humans

For nearly a century, scientists have been puzzling over fossils from a strange and robust-looking distant relative of early humans: Paranthropus robustus. It walked upright, and was built for heavy chewing with relatively massive jaws, and huge teeth with thick dental enamel. It's thought to have lived between 2.25 million and 1.7 million years ago.