03/15/2012 11:15 EDT | Updated 05/15/2012 05:12 EDT

Fossils in China reveal new Stone Age people

Four sets of mysterious human-like fossils found in China may offer insight into a previously unknown Stone Age people, according to an international team of scientists.

The remains were found in two caves in southwest China. They're the earliest discovery of their kind and thought to be at least 11,000 years old.

The scientists, however, are cautious about making firm judgments about the fossils as they have a mix of modern and archaic features.

“These new fossils might be of a previously unknown species, one that survived until the very end of the Ice Age around 11,000 years ago,” said Darren Cunroe in a press release from the University of New South Wales, Australia.

Cunroe, an associate professor at the university, is leading the study, working with Prof. Ji Xueping from the Yunnan Institute of Cultural Relics and Archeology.

“Alternatively, they might represent a very early and previously unknown migration of modern humans out of Africa, a population who may not have contributed genetically to living people,” Cunroe said.

The fossils were first found decades ago, and stored until the late 2000s, when the team of scientists from five Australian and six Chinese institutions began examining them.

In 1979, a partial skeleton was discovered encased in rock by a Chinese geologist in Guangxi Zhuang Autonomous Region. It was removed from the rock and reconstructed in 2009 by the team.

Three other fossils were found in 1989 nearby in Yuannan Province at Maludong, also called Red Deer Cave. It is believed that these people hunted and cooked the now-extinct red deer. Studies on these fossils started in 2008.

The team’s results have been published in the journal PLoS One from the Public Library of Science.