Wushan Man
Wushan Man is a set of fossilised remains of an extinct, undetermined non-hominin ape found in central China in 1985. The remains are dated to around 2 million years ago and were originally considered to represent a subspecies of Homo erectus.
The remains that have become known as "Wushan Man" were found in 1985 in Longgupo, Zhenlongping Village, Miaoyu Town of Wushan County, Chongqing in the Three Gorges area of China south of the Yangtze River.
History of find
The cave at Longgupo is called "Dragon Bone Slope", due to the way the collapse of the cave's roof and walls shaped the above land.fig. 1 It was discovered as a site containing fossils in 1984 and then initially excavated by a team of Chinese scientists, led by Huang Wanpo of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing and the Chongqing National Museum from 1985 to 1988. The deposits on the cave floor are over 22 m deep, with the 10 m containing fossils overlain by 12 m that do not.fig. 2In 1986, three fore-teeth and a left mandible with two molars were unearthed together with the animal fossils including teeth from an extinct type of large ape Gigantopithecus and an extinct pygmy giant panda Ailuropoda microta. Excavations carried between 1997 and 1999 and then between 2003 and 2006 have found additional stone tools and animal fossils including remains of 120 species of vertebrates, of which 116 are mammals. This suggests the fossils existed originally in a subtropical forest environment.
The presence of Sinomastodon, Nestoritherium, Equus yunnanensis, Ailuropoda microta remains in the level containing the jaw suggested that its remains belonged to the earliest part of the Pleistocene or late Pliocene. Dating of the layers containing the fossil remains was initially done using archaeomagnetic dating of traces of the Earth's ancient magnetic field. These confirmed a Pleistocene age linking the fossil jaw to around 1.78 million to 1.96 million years ago and so the same time as the human fossils that appeared in Africa's Olduvai Gorge. Later in 1992, a joint Chinese-American-Canadian research team using electron spin resonance dating and a deer tooth from one of the cave's upper levels three meters above that containing the jaw dated this level to a minimum age of 750,000 years and a most likely age of 1 million making the layers below at least and probably much older in date than this. More recent dating techniques suggest the layer containing the fossils are 2 million to 2.04 million years old.
Early reports of the excavation were in Chinese journals and did not gather attention from outside China. In 1992, Russell Ciochon was invited to Longgupo to examine and provide a reliable age for the jaw. This led to the published in 1995 by Ciochon and Chinese paleoanthropologist of the findings in the journal Nature.
Importance
According to the Nature paper:
The new evidence suggests that hominids entered Asia before 2 Myr, coincident with the earliest diversification of genus Homo in Africa. Clearly, the first hominid to arrive in Asia was a species other than true H. erectus, and one that possessed a stone-based technology. A pre-erectus hominid in China as early as 1.9 Myr provides the most likely antecedents for the in situ evolution of Homo erectus in Asia.p. 278
This makes its status as a Homo fossil critically important to the study of human origins as it suggests that H. erectus was not the first human species to leave Africa and supports the argument made by some that H. erectus evolved in Asia and not Africa.
The discovery of Homo floresiensis also makes evidence of a pre-erectus hominin in Asia important. Recent research finds its wrist and foot bones to be anatomically like those of H. habilis or Australopithecus. Evidence for pre-erectus Homo in Asia would be consistent with such a possible origin.
Reflecting its status, a middle school textbook, The Chinese History, has been planned that includes the discovery of "Wushan Man".
Early doubts
In a Science report in 1995 upon the finding several doubts were raised including one by Milford Wolpoff
Milford Wolpoff of the University of Michigan, who saw the specimens on a trip to China several years ago, isn't even convinced that the partial jaw is a hominid. "I believe it is a piece of an orangutan or other Pongo," he says. He bases that conclusion on a wear facet on the preserved premolar, which to him suggests that the missing neighboring tooth is shaped more like an orang's than a human's.p. 1117
Jeffrey Schwartz and Ian Tattersall published a claim in Nature that the teeth found in Longgupo were those of an orangutan. But the teeth are outside the range of variation of those found in orangutans ruling out this possibility.
More recently, the jaw fragment has been argued to be indistinguishable from Late Miocene-Pliocene Chinese apes of the genus Lufengpithecus. The incisor has also been argued to be consistent with that of an East Asian person that accidentally entered the deposit: "brought in by flowing water or other forces into the fissure of the comparatively old Longgupo Cave deposits".
Retraction
In the 18 June 2009 issue of Nature, Russell Ciochon who first reported the jaw fragment from Longgupo as human announced that he now had changed his mind and considers that it belongs to an unknown extinct ape.
I am now convinced that the Longgupo fossil and others like it do not represent a pre-erectus human, but rather one or more mystery apes indigenous to southeast Asia’s Pleistocene primal forest. In contrast, H. erectus arrived in Asia about 1.6 million years ago, but steered clear of the forest in pursuit of grassland game. There was no pre-erectus species in southeast Asia after all.
Russell Ciochon changed his mind since he no longer believes as he did earlier that Gigantopithecus and H. erectus coexisted in the same environment—an argument he had made book in 1990 Other Origins: The Search for the Giant Ape in Human Prehistory.
Without the assumption that Gigantopithecus and H. erectus lived together, everything changed: if early humans were not part of the Stegodon–Ailuropoda fauna, I had to envision a chimpanzee-sized ape in its place — either a descendant of Lufengpithecus, or a previously unknown ape genus.p. 911A key factor in changing his opinion was a visit in 2005 to the Guangxi Natural History Museum in Nanning where he examined a large number of primate teeth from the Pleistocene. He also feels that early humans did not live in subtropic forests that existed at Longgupo at that period.
Homo erectus, it seems from this perspective, hunted grazing mammals on open grasslands, and did not or could not penetrate the dense subtropical forest.
While Russell Ciochon no longer believes the jaw to belong to a human, he still claims the two stone tools found with them were made by humans. But according to him, "They must have been more recent additions to the site."p. 911
Jeffrey Schwartz, one of the critics of the original claim that the jaw was human, has been quoted as noting about Ciochon's retraction that it is "really astonishing. It is not often that a scientist says he changes his mind. This openness is good."