KUNMING -- Chinese palaeobiologists have identified a new mammal ancestor and indicating that marsupials may not have originated in Asia.

Well-preserved skeletons of Ambolestes zhoui from 126 million years ago were found in Yixian county in North China's Inner Mongolia autonomous region, said Professor Bi Shundong of Yunnan University palaeobiology lab, who led the research.

Over the past 20 years, fossils of 120 vertebrate species, generally known as the Jehol biota, have been found in the Mesozoic site.

The skeletons show details unknown in contemporaneous mammals after researchers used CT and 3D technology to reconstruct the structure of every bones, said Bi.

"Ambolestes zhoui is an early member of the placental lineage. It also carries mixed features both placentals and marsupials," he said.

"Our conclusion means that Asia may not be the place of origin for marsupials," he said. The oldest known marsupials are from 110 million years ago from west North America.

On the basis of the research, researchers have also established a database on the lineage of early mammals.

The research findings are published in the Nature science journal.