for National Geographic News
Nearly 15 years ago Russell Ciochon shook our family tree when he announced that a fossil found in a Chinese cave was evidence of a new form of early human.
But that was then.
Today the anthropologist announced that the fossil, a partial jaw, is from an ape after all—a "mystery ape." And as controversial as the original theory was, Ciochon's reversal is also meeting with some criticism.
The fossil was found in the 1980s in south-central China's Longgupo cave. According to Ciochon, "the jaw was very perplexing. It didn't fit in any category of hominin [early human ancestor] that we knew of in Asia, and it also didn't fit into any ape category."
Ciochon and colleagues theorized that the fossil represented an unknown hominid who lived in Asia 1.9 million years ago—about a million years earlier than early humans are generally thought to have arrived in the region.
The ancient hominin, Ciochon's team suggested in 1995, was a more primitive species than Homo erectus, the human ancestor thought to have migrated from Africa and populated Asia (interactive map of prehistoric human migrations).
The 1995 theory implied that a line of H. erectus could have evolved independently in Asia.
Teeth Take Bite Out of Theory
As the years passed, Ciochon recounted, new evidence caused him to reconsider the disputed fossil.
First, in 2000 and 2001, scientists showed that the Longgupo jaw had teeth that had strong similarities to those of the older, extinct ape Lufengpithecus, a possible orangutan ancestor.
Then, in 2005, Ciochon examined the large collection of primate teeth from the Pleistocene epoch (about 1.8 million to 11,500 years ago) at the Guangxi Natural History Museum in Nanning, China.
The collection, from a well-documented cave site, included some unidentified primate teeth that strongly resembled those in the Longgupo jaw—and that's when Ciochon was convinced.
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