The oldest recorded fossils of adult frogs date back to around 217 million years ago, in the Late Triassic Period, but the oldest preserved tadpoles had been from roughly 140 million years ago, in the Cretaceous. The remains, uncovered in January 2020 and described in the journal Nature on Wednesday, shed light on the history of frog metamorphosis.

Scientists have discovered the oldest-known fossil of a tadpole, which lived among the Jurassic dinosaurs 160 million years ago.