This new discovery of frogs frozen in amber along with plants, insects, and other organisms is an incredibly important resource to learn more about the plants and animals living in these forests. "Electrum" is Latin for "amber", "rana" Latin for "frog", and "limoae" likely refers to the researcher who either found them or identified them, in keeping with the scientific tradition of naming new species after either their discoverer, identifier, or someone the scientist admires.
"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. Prior to this fossil discovery, the oldest known fossilized frog was only 25 million years old, illustrating the difficulty of learning about these animals' history.
"Whilst Electrorana doesn't preserve much soft tissue, unlike some fantastic lizard specimens from the same deposits, its well-preserved skeleton represents the oldest record of a frog from a tropical forest, which is a very important modern habitat for frogs", says Michael Pittman, a paleontologist at the University of Hong Kong.
An illustration shows how the ancient frog may have become trapped in tree resin that went on to create the amber fossil. Unfortunately, in the recently discovered fossils, those crucial parts were either missing or had not yet fully developed in the young frog. "But surprisingly, we have nearly nothing from the fossil record to say that's a longstanding association". Frogs are thought to be at least as old as 200 million years old, but it's almost impossible to learn much about the early amphibians - due to their small size and biology, they don't fossilize easily and most of the extinct frog remains are long gone.
"Lizards and frogs in amber are certainly not unheard of, but ones this old are exceptional", says Marc Jones, an expert on fossil frogs based at the Natural History Museum in London, U.K. The yellow and vibrant shaped amber is visible and in which one could see the skeletal system with the limbs and the skull distinctively. He said his role in the project was to scan and describe the fossils.
Photographs of four fossil frog specimens referred to Electrorana, including the holotype (A) and three additional specimens (B-D); specimens in (B) and (D) are presented with two views of the amber specimen and the oval in (D) indicates the presence of the frog specimen.
The species could have lived in ponds near the Hukawng Valley and fed on mosquitoes, beetles, spiders and other creatures that didn't have a backbone. These include the wrist bones, the pelvis and hip bones, the inner ear, and the top of the spine.
Or, "early" in the sense that it's early for us, less so for the frogs.
But Electrorana raises more questions than it answers, Blackburn says. It seems extremely unlikely that there's only one. The findings were just published in Nature.