For an animal that already looks assembled from spare parts, the platypus has added another twist to its history. Fossils from South Australia point to an ancient species, Obdurodon insignis, that looked a lot like the modern platypus but still carried a full set of crushing teeth. Living platypuses do not. Adults use tough grinding pads instead, one of the features that make them stand apart from nearly every other mammal on Earth. That contrast matters because the new remains do more than add another strange detail to an already strange animal. They suggest the platypus body plan had settled into something close to its modern form by the late Oligocene, around 25 million years ago, even before the living species lost its teeth. “Platypuses are extremely rare in the fossil record and are often restricted to teeth, so it’s exciting to find new material and learn more about these unique mammals,” said study co-author Dr. Aaron Camens of Flinders University. Palaeontologists found one fossil at the Billeroo Creek site in 2017. (CREDIT: Aaron Camens) …