By Tanya Lewis, Staff Writer | March 04, 2014 03:13pm ET
A fossil bed in China that contains some of the world's most exquisitely preserved feathered dinosaurs, early birds, reptiles and mammals may also be home to an equally rich set of older fossils from the Middle Jurassic, a new study finds.
These older fossils, dating back about 160 million years, contain theearliest known gliding mammal, earliest swimming mammal, a flying reptile and the earliest feathered dinosaurs. Now, a new study classifies these fossils as belonging to a distinct ecological group, or biota.
The new biota was found in layers of rock beneath the so-called Jehol Biota, a famous collection of 130-million-year-old fossils from China's western Liaoning Province and nearby northeastern China; the Jihol organisms are now thought to have been killed and preserved in aPompeii-style eruption. In recent years, fossils that are 30 million years older have surfaced from beneath the Jehol Biota, but have not been definitively linked to the same time period.