Around 80,000-120,000 years ago, the first modern humans left Africa for the first time and settled in the jungles of prehistoric China.

For centuries, we thought our ancestors were the only human species who populated China. To the west of China lived the Neanderthals, our extinct hominin cousins. The Neanderthals thrived in Europe and West Asia until their mysterious demise around 40,000 years ago (which, coincidentally, is the same time that modern humans arrived in Europe).

Another archaic species, Denisovans, lived in Siberia. They, too, were erased from existence around the same time as the Neanderthals. Alas, we were the last remaining human species. Or so we thought.

It turns out, we weren’t alone in China. According to a new PLOS One study shared by Reddit user jupiter_orbiter in the Reddit science community, a 14,000-year-old partial thigh bone found in southwestern China may belong to a distinct species of humans dubbed the “Red Deer Cave People.”

The femur bone was originally found in 1989 along with other fossils in the Red Deer Cave in Yunnan Province. The bones remained unstudied until years later.

Some scientists suspected that the bones found in the cave may be from another species—but they were unsure since some of the fossils found had features similar to modern humans. All in all, the science community was divided since the results were inconclusive. Whether they were modern humans or not, scientists called them the “Red Deer Cave People” since they hunted extinct red deer.

New evidence, however, points to the Red Deer Cave People being a distinct species of their own.

Scientists discovered that the femur bone is actually similar to the bones of early Homo erectus, which is strange because Homo erectus lived 1.5 million years ago in Africa.

“[Red Deer Cave People] anatomy was nothing like we’d seen before in modern humans, whether they lived 200,000 or 200 years ago: they were truly unique and a real mystery to us and many of our colleagues,” writes one of the team’s researchers, Darren Curnoe, in the Conversation.

The findings, of course, are controversial since it means a new species intermingled and possibly bred with anatomically modern humans for millennia.

“Despite the progress we’re making about these and other ancient humans in Southwest China, we’re left with many riddles still about the Red Deer Cave people. Just who exactly were these mysterious Stone Age people? Why did they survive so late? Why are they found only in tropical Southwest China? We hope to be able to answer more of these questions soon,” says Curnoe.