Prehistoric frogs preserved in amber for 99 million years provide the earliest evidence that the amphibians once lived in tropical rainforests.
The frogs that were trapped in amber were not as massive as the so-called devil frog that lived in Madagascar 65 million to 70 million years ago. However, their discovery still holds significant importance in the quest to understand the ancient world.
Ancient Frogs Preserved In Amber
The discovery of four small frogs that have been preserved in amber for 99 million years is the focus of new research that was published on the Scientific Reports journal.
The study determined that frogs, which emerged about 200 million years ago, were living in soggy forested areas at least 100 million years ago. This discovery is important because of the rarity of finding fossils of forest amphibians, so scientists have not been sure on when frog populations started occupying tropical habitats.
According to study coauthor David Blackburn, Florida Museum of Natural History's associate curator of amphibians and reptiles, the frogs of today are common in wet tropical forests. In fact, over a third of the almost 7,000 frog species call tropical rainforests their home.
However, Blackburn noted that small animals living in tropical forests have a very low chance of leaving behind fossils, which makes it hard to study their ancient history.
Animals Trapped In Amber
The four frog fossils, discovered in Kachin State, Myanmar, have been preserved in amber since the end of the age of the dinosaurs. They were described by Lida Xing, from Beijing's China University of Geosciences, as a "miracle" find.
"In China, frogs, lizards and scorpions are called three treasures of amber," Xing said to BBC News, adding that the frog fossils preserved in amber provide evidence that the amphibians lived in tropical rainforests before dinosaurs died off at the end of the Cretaceous period.
The frogs have been named Electrorana limoae by the researchers, with the amphibians measuring less than an inch long when they were alive. However, they were not the only animals discovered in amber in Myanmar. Plants, spiders, and other insects have also been found, alongside marine mollusks that suggest the frogs lived in ecosystems that contained freshwater lakes.
The frog fossils came from the same amber deposits in Myanmar where fossils of a dinosaur tail, baby birds, bird wings, and insects have been found. The frogs preserved in amber were given by private Chinese collectors as donations to the Dexu Institute of Paleontologu in Chaozhou, China.