A veritable Jurassic paradise is providing an exceptional window on life approximately 160 million years ago.

The fossil assemblage, called the Daohugou Biota, is described in the latest issue of the Journal of Vertebrate Paleontology. The fossils, all found in and around what is now Inner Mongolia, China, date from a time when many important animal groups, including our own (mammals), were undergoing noteworthy evolutionary changes.

Photos: Living Fossils: Animals from Another Time

The collection features such memorable creatures as the oldest known gliding mammal, another early mammal that may have swum with a beaver-like tail, the oldest dinosaurs preserved with feathers and a pterosaur that represents an important transitional form among these now extinct, warm-blooded flying reptiles.

“The Daohugou Biota gives us a look at a rarely glimpsed side of the Middle to Late Jurassic — not a parade of galumphing giants, but an assemblage of quirky little creatures like feathered dinosaurs, pterosaurs with advanced heads on primitive bodies, and the Mesozoic equivalent of a flying squirrel,” lead author Corwin Sullivan, an associate professor at the Institute of Vertebrate Paleontology and Paleoanthropology, was quoted as saying in a press release.

The collection also includes complete, or nearly complete, skeletons associated with preserved soft tissues such as feathers, fur, skin or even, in some of the salamanders, external gills. Preserved anatomy like that, according to co-author Yuan Wang, helps to reveal how very early amphibians and other animal groups evolved, spread out, and diverged into additional species.

Paul Barrett, a dinosaur researcher at the Natural History Museum, London, said, “Daohugou is proving to be one of the key sites for understanding the evolution of feathered dinosaurs, early mammals and flying reptiles, due largely to the fantastic levels of preservation. Many of the fossils are stunning and offer vast amounts of information.”

Fossil Shows Pre-Dino Reptile Giving Birth

The treasure trove of fossils, all from approximately the same time period and region, date to 30 million years before yet another fossil collection, known as the Jehol Biota. The latter consists of feathered dinosaurs, early birds and mammals that were collected from the western Liaoning Province and adjacent parts of northeastern China. It has shed incredible light on what animal life was like during the Cretaceous Period.

But this newly identified Jurassic collection appears to be just as fossil-rich and important.

Although the two collections are separated by millions of years, comparing and contrasting the finds reveals how dinosaurs, mammals, amphibians and other animal groups from basically the same area changed over time. The feathered dino finds alone are remarkable.

As Sullivan said, “The Cretaceous feathered dinosaurs of northeastern China have been astonishing paleontologists and the public for almost two decades now, and the Daohugou Biota preserves their Jurassic counterparts in the same region. As prequels go, it’s pretty exciting.”

(Image: Julia Molnar)