SHENYANG -- Two well-preserved pieces of Jurassic animal fossil were discovered in north China's Hebei Province, according to the journal Nature.

The discovery of the two gliding Euharamiyidan mammal fossils, dating back to the Jurassic Period at 164 million and 159 million years ago respectively, was published in Nature on Nov. 14.

The fossils were discovered at the beginning of 2014, and October 2015 successively in Nanshimen village of Qinglong county by scientists from Chinese and American institutions.

The scientists have been restoring and analyzing the fossils over the past few years, and concluded that the discovery has proved the diversity of the ancient mammal species, which is of great value to the study of the evolution of the mammalian middle ear.

The species' middle ear preserved in the fossils, with five auditory bones, is different from that of other known mammals, both in the number and morphology of auditory bones.

One of the fossils also show the details of the species' gliding membrane, offering important information to scientific studies.

Euharamiyidan mammals are an extinct species that lived in forests from the late Triassic to late Jurassic Period. Their fossils were first discovered in Europe in 1847.

In 2005, Chinese cultural workers first discovered fossils of the animal in Xinjiang Uygur Autonomous Region.