China's Jurassic Park is slowly revealing its paleontological secrets and rewriting what we know about dinosaur evolution, early mammals and their shared ecosystem.
In the past decade, many of the more exciting finds in paleontology have been taking place in the Far East - in areas like the Jehol region of northeast China, which has come to be known as the country's "Jurassic Park." That's where a volcanic explosion similar to the legendary Pompeii eruption took place in the distant past, engulfing the entire landscape in a lake of fire and ash, but preserving everything underneath. Many of the animals - from carnivorous dinosaurs to prehistoric minnows - died from suffocation before being buried.
"How could you possibly know anything about an extinct ecosystem?" goes the line from the recently released Jurassic World blockbuster film. Now, that may no longer be the case thanks to the discovery in Jehol of layer upon layer of extinct animals, many of which have been previously unknown to science.
As a result, we have a well-crafted mural of what life was like in the Jurassic period, 160 million years ago - a biota record of the animals, plants, and even bacteria. These days we take for granted the notion that "dinosaurs evolved into birds," but the evidence that officially sealed the deal was found here.
Dinosaur fossils buried in fine grain sediments in Jehol had feather imprints surrounding their remains, which tested positive for beta-keratin, one of the most prominent proteins in bird feathers. These discoveries have lead to the widely accepted belief that most dinosaurs had feathers at one point in their lives, perhaps for use as insulation or for attracting mates. At some time in the Jurassic period, birds and dinosaurs diverged, with the former surviving until today. This evidence too is hidden in the rocks at Jehol, where preserved soft tissue from meat-eating dinosaurs like Anchiornis huxleyi suggests a fast metabolism similar to birds.
What's most astonishing about the Jehol biota are the fossils that make us rethink the world the dinosaurs inhabited. We tend to imagine them all living in lush jungles; in reality, flowering plants only came about shortly before their extinction, and grass only began to evolve during the Jurassic period - evidenced by blades of grass preserved in amber. Instead, the Jehol was full of conifers, the perfect hiding spot for small mammals that lived alongside predacious dinosaurs.
Mammals were much more diverse at this time than originally thought. Now, evidence from Jehol suggests that by the Jurassic period, they were swimming - like Castorocauda lutrasimilis. This beaver-like creature had webbed feet, a scaly tail and sharp teeth, as well as multiple layers of fur for navigating cold water. Swimming was an evolutionary achievement that scientists previously thought took place just 55 million years ago. Meanwhile, Volaticotherium antiquus, a prehistoric glider squirrel, suggests mammals may have taken to the air even before birds did.
Paleontologist David Hone, of Queen Mary University in London, is confident bird remains will be found at Jehol within the next 10 years, giving us the chance to examine an incredible evolutionary roadmap - from theropod dinosaurs to present-day birds.