Scientists in Argentina unearth oldest tadpole, from dinosaur times

Scientists in Argentina have discovered excellently preserved fossil remains of the oldest-known tadpole, the larval stage of a large frog species that lived alongside dinosaurs about 161 million years ago during the Jurassic Period.

The researchers said the fossil, measuring 16 centimeters (6.3 inches) long, sheds light on the evolution of frogs and toads, showing that tadpoles today are largely unchanged from their forerunners in the Jurassic. The oldest-known frog fossils date to even earlier...