Scientists have uncovered the oldest-known fossil of a tadpole that wriggled around 160 million years ago. Found in Argentina, the new fossil surpasses the previous record holder by about 20 million years. Researchers know frogs were hopping around as far back as 217 million years ago. But how and when they evolved to begin as tadpoles remains unclear. This new discovery adds some clarity to that timeline. The ancient fossil is strikingly similar to the tadpoles of today. The research was published Wednesday in the journal Nature.
