An earlier installation of this column discussed the fierce controversy among paleoanthropologists (scientists who study ancient human origins) over two famous recent fossils: Orrorin tugenensis, found in Kenya in 2000, and Ardipithecus ramidus, dug up in Ethiopia from 1994 to 1996. According to the September 24, 2004, issue of the prestigious journal Science,
Tempers flared last week in a sweltering salon at the French Academy of Sciences here [at a conference on Prehistoric Climates, Cultures, and Societies] as scientists hotly debated the attributes of anthropology’s most famous thighbone, the 6-million-year-old femur of an ancient Kenyan hominid called Orrorin tugenensis (Gibbons 2004: 1885).
Orrorin’s discoverers claim that this creature, based on the remains of its thighbone, was bipedal (that is, it walked upright), a characteristic that marks an ancient primate as a genuine human ancestor. According to Science, “Bipedalism is a traditional hallmark of membership in the human family rather than being an ancestor of chimpanzees, gorillas, or quadrupedal apes [apes that walk on all fours]” (Ibid.).
At the conference, Brigitte Senut of the National Museum of Natural History in Paris, the co-discoverer of Orrorin, presented a computed tomography (CT) scan of Orrorin’s incomplete thighbone. She asserted that certain aspects of this bone “suggest that the hips were stabilized in a manner similar to those of modern humans. In fact, Senut proposed that Orrorin’s gait was more humanlike than that of the 2- to 4-million-year-old australopithecines [the family that includes the famous ‘Lucy’]. If so, australopithecines would be bumped off the direct line to humans—a dramatic revision of our prehistory” (Ibid.).
But Tim White of the University of California at Berkeley, co-discoverer of ramidus and a major contributor to the discovery of “Lucy,” disagreed strongly. According to Science, White “immediately attacked this view of Orrorin,” saying that the resolution of Senut’s CT scan was so poor that it was impossible to examine the pattern of bone thickness with any accuracy. CT scan expert James Ohman of Liverpool John Moores University “agreed that the published scans were taken at the wrong angle” (Ibid.). The prestigious journal then reported:
White accepts that Orrorin walked upright and so is one of the first members of the hominid family. But he says Senut has offered little evidence as to Orrorin’s gait. ‘Was it human, an Australopithecus pattern, or something different?’ he asked. Even standard x-rays would help answer that question. As the discussion grew more heated, White called Senut’s displacement of australopithecines ‘une position créationniste,’ because it suggests that Orrorin’s femur was quite modern 6 million years ago, rather than evolving in stages (Ibid. [all italics original]).
Senut responded by asking White to provide evidence that ramidus was what he claimed it to be. White reacted by displaying CT images of the ramidus skull that he had dug up back in the 1990’s. As Science reported, “The CT scans were startling: The skull was so crushed that the top of the vault was smashed almost to the base, forming a slab of hundreds of chalky pieces. White described it as ‘road kill’” (Ibid.).
Both sides of this controversy are equally adamant, and furious, in trying to prove that their particular discovery is THE true human ancestor. This shows that the search for human origins is not a purely scientific endeavor, but is fraught with personal animosity and the desire to be the first paleontologist to prove that humans evolved from lower animals.
Gibbons, A. 2004. “Oldest Human Femur Wades into Controversy.” Science 305, no. 5692.