Tiny fossils reveal backstory of the most mysterious amphibian alive

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Researchers have determined that the fossils of an extinct species from the Triassic Period are the long-missing link that connects Kermit the Frog's amphibian brethren to wormlike creatures with a backbone and two rows of sharp teeth.

Named Chinlestegophis jenkinsi, the newfound fossil is the oldest relative of the most mysterious group of amphibians: caecilians. Today, these limbless, colorful serpentine carnivores live underground and range in size from 6 inches to 5 feet.

The study, published in Proceedings of the National Academy of Sciences on June 19, expands the known history of frogs, toads and salamanders by at least 15 million years and closes a major gap in early caecilian evolution by connecting them to stereospondyls, animals with toilet-seat heads that were the most diverse amphibian group during the Triassic era more than 200 million years ago.