Ancient human ancestor emerges in China.

A collapsed cave in south central China has yielded evidence that human ancestors inhabited the far reaches of Asia as early as 1.9 million years ago, according to a report in the Nov. 16 Nature.

Finds at the site support the theory that the genus Homo spread from Africa to Asia more than 2 million years ago, an international research team asserts. Moreover, they add, those ancient travelers belonged to a species that arose before H. erectus, long considered the first human ancestor to settle in Asia.

"The concept of hominids prior to erectus living outside Africa will be hard for some [researchers] to accept," contends Russell L. Ciochon, an anthropologist at the University of Iowa in Iowa City. "The new findings will shake up theories of Homo evolution."

His contention rests on discoveries made at Longgupo Cave, excavated between 1985 and 1988 by Chinese paleontologists. Huang Wanpo of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing directed the project. Investigators found the remains of numerous fossil mammals, including the extinct ape Gigantopithecus. A partial jaw and an isolated tooth of what they initially classed as H. erectus also turned up, as well as two volcanic rocks that had been intentionally battered along their edges.

In 1990, Ciochon assembled a group of researchers to join the Chinese effort at Longgupo Cave. Animal bones found near the hominid remains, such as those of an ancestor of the giant panda, suggested an age of 1.5 million to 2 million years. Magnetic reversals in the cave's soil layers further indicated that the hominid material ranged from 1.78 million to 1.96 million years old.

A separate dating technique called electron spin resonance (ESR), based on the accumulation of radioactive elements in bone, placed a deer tooth found 10 feet above the hominid remains at 1.02 million years old. This matches the age estimate for the same sediment reached through magnetic analysis, Ciochon says. Specimens from the hominid-bearing layer have yet to undergo ESR dating.

Ciochon and his coworkers now assign the Chinese hominid fossils to an as yet undetermined species that lived before H. erectus. In particular, they argue, the Longgupo finds resemble two East African hominids, H. habilis and H. ergaster, which date to around 2 million years ago. A Longgupo premolar  tooth, for instance, features two cusps at the front and a basin in the middle, as in H. habilis, and two roots, as in H. ergaster. A Longgupo molar has five cusps, as in both African species. None of these dental traits appears in available H. erectus specimens from China and Java, Ciochon holds.

Several Homo species began to evolve around 2.6 million years ago in Africa, and one of those groups may have trekked across Asia not long afterwards. H. erectus may have evolved in Asia from the species found at Longgupo, the Iowa scientist theorizes.

The Chinese fossils offer "meager pickings" but so far support Ciochon's analysis, write Bernard Wood and Alan Turner of the University of Liverpool in an accompanying comment.

However, the Longgupo teeth show as many similarities to H. erectus teeth from Java as they do to teeth of African hominids, asserts G. Philip Rightmire of the State University of New York at Binghamton. If H. erectus specimens in Java indeed date to 1.8 million years ago, as recently proposed (SN: 3/5/94, p.150), the Longgupo hominid may represent an early member of the same species, says Rightmire.