A study published this week in Nature’s Scientific Reports reveals the rare discovery of four frogs impressively well-preserved in amber, the oldest-known examples of frogs preserved in such a manner. More importantly, the fossil records provide evidence that frogs existed in forested regions at least 99 million years ago, giving scientists a better idea about when the amphibians could have begun their migration into tropical habitats.

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“It’s almost unheard of to get a fossil frog from this time period that is small, has preservation of small bones and is mostly three-dimensional. This is pretty special,” said in a statement David Blackburn, study co-author and the associate curator of herpetology at the Florida Museum of Natural History.

“But what’s most exciting about this animal is its context. These frogs were part of a tropical ecosystem that, in some ways, might not have been that different to what we find today – minus the dinosaurs," he added.

Electrorana limoae

The fossil records of the extinct species, that has now been named Electrorana limoae, were found in northern Myanmar in Southeast Asia. Frog fossils, due to the amphibian's delicate nature, do not preserve well in general and those preserved in amber are notoriously rare.

The only two previous specimens were found in the Dominican Republic and Mexico. Studies found they dated only approximately 40 million and 25 million years respectively, meaning the current discovery now consists of the earliest direct evidence of frogs living in tropical forests.