Jaw fossils point to multiple origins of the most mammalian of features
Tom Rich has an eye for finding bits of skulls in unlikely places. In January, he and his team reported finding a slight groove in a half-inch–long jaw. Using a modified CT scanner, the researchers scrutinized the fossil they had unearthed in Australia a few years earlier. Reviewing the images of the jaw's structure, Rich and collaborators saw the groove and realized they held what remained of a duck-billed platypus out of place in the age of dinosaurs.