Field of Science

Is Eoanthropus dawsoni a valid species?

"It's better to ask some questions than to know all the answers."
James Thurber, American writer and illustrator (1894-1961)

At the beginning of the twentieth century the search for our ancestors - the supposed "missing links" between man and the animal kingdom was a crucial point in the new emerging field of human palaeontology. First results came from Germany with the discovery in 1907 of a jaw with mixed characteristics between apes and humans - a good start, but scientists wanted something even better.

Only a year later some workers discovered strange bones in a gravel pit near the village of Piltdown in southern Sussex and consigned them to the lawyer, antiquarian and amateur geologist Charles Dawson.
Dawson initiated with the help of Arthur Smith Woodward, keeper of the geological department at the British Museum, a private prospection campaign in the gravel pit. Dawson already had experience in digging up fossils, many of which he donated to the museum, and was a respected fellow of the Geological Society.
Between June and September of 1912 several fragments of a human skull, along with bones of Pleistocene animals like elephant, teeth of mastodon and beaver and finally during a "warm summer evening" (so Woodward) the half of a jaw, that fit with the human skull, were unearthed.

Fig.1. A photograph by John Frisby of Uckfield, showing excavations at the Piltdown gravels in 1912. Standing centre left in the picture is the white-bearded figure of Arthur Smith Woodward and working in the trench on the right is Charles Dawson, the local solicitor who had "discovered" the skull of "Piltdown Man" (by Sussex PhotoHistory Home Page).

Woodward begun secretly with the reconstruction of the entire skull, it resembled that of modern man, except for the part where the skull is attached to the spinal cord and the cranial volume, with an estimated brain volume of 1070ccm (about two-third of modern humans). The jaw was indistinguishable from that of a modern, young chimpanzee, except by the presence of two molars identical to human ones.

On December 18, 1912 Woodward presented the complete reconstruction in front of a large audience and suggested that the fossil represent an evolutionary missing link between ape and man, since the combination of a large cranial capacity with the jaw of a monkey seemed to support the notion that the main characteristic of human evolution was the early development of the brain. The reconstruction was harshly criticized, especially by anthropologists and archaeologists from the continent.
Many of these experts noted that the fragments didn't fit or even necessarily belong together; the anatomist Arthur Keith at the Royal College of Surgeons produced a reconstruction quite identical to a modern man (Homo piltdownensis), Marcellin Boule, a French archaeologist affirmed in 1921 that the remains belong to two different species - if it was not entirely a hoax. This conclusion was supported by the American zoologist Gerrit Smith Miller, who however attributed the jaw to a still undescribed species of chimpanzee, informally named Pan vetus. The German anthropologist Franz Weidenreich examined the remains and reasserted that the presumed fossil was simply a modern human skull and an orang-utan jaw with manipulated teeth.
But finally there were no conclusive evidence to assert that the entire story was a fake and the British scientific community accepted the new species as Eoanthropus dawsoni.
Over the years further discoveries were made at Piltdown: bones of animals, an object that resembled a cricket bat (!) and supposedly two more skulls. It was in 1915 that Dawson claimed to have found fragments of a second skull (called Piltdown II) in a not specified site about two to three miles away from the first site, however Woodward himself seems never to have visited this site. Dawson died in August 1916, leaving Woodward with the heredity of Piltdown, who in 1917 continued to present material to support the alleged Piltdown Man.

However in the next three decades discoveries on the African continent seemed to contradict the hypothesis based on the genus Eoanthropus, ancient biped hominids were found only in Africa and the cranial capacity did not differ significantly from chimpanzees.


In October 1948 the geologist Kenneth Oakley decided to apply a new dating method and analyzed the fluorine concentration in the bones of the Pleistocene animals and compared the results with the remains of the Piltdown man. While the bones contain up to 3% fluorine, Piltdown showed just 0,2%, it was not possible that both the bones as the skull lay underground side by side for thousand of years.

This seemed the end of the Piltdown man, but recent discoveries now again cast new light on the evolution of humans. The fossil bones of Homo floresiensis of Indonesia, the genetic analysis of the human remains of Denisova in Siberia and controversial early H. sapiens teeth discovered in Israel have shown that the model of a unique migration out from Africa was too simple. It is possible that diverse migration waves occurred and that single populations of hominids evolved separately in various forms - this could possibly explain also the repeated sightings of large biped apelike creatures all around the world in recent times.
For Eoanthropus this means that it is possibly a younger descendant of a common ancestor to modern humans, as supported by the relative young age inferred by the low concentration of fluorine, with evolved characteristics, like the large brain, and atavistic characteristics, like the orang-utan jaw. The preliminary results of the new hypothesis and the official (re)recognition of the species Eoanthropus dawsoni will occur in London on 29, April 2011, as a tribute and wedding present to the British Crown.

Bibliography:

HERSHKOVITZ, I.; SMITH, P.; SARIG, R.; QUAM, R. RODRIGUEZ, L.; GARCIA, R.; ARSUAGA, J.L.; BARKAI, R. & GOPHER, A. (2010): Middle pleistocene dental remains from Qesem Cave (Israel). American Journal of Physical Anthropology. Vol. 144(4): 575-592
KRAUSE et al. (2010): The complete mitochondrial DNA genome of an unknown hominin from southern Siberia. Nature online publication 24 March 2010: doi:10.1038/nature08976
REICH. D. GREEN, R.E.; KIRCHER, M.; KRAUSE, J.; PATTERSON, N. et al. (2010): Genetic history of an archaic hominin group from Denisova Cave in Siberia. Nature 468: 1053-1060

Online resources:

Anonymous (): Welcome To the Piltdown Plot!
(Accessed 01.04.2011)
Bournemouth University (2010): Piltdown Man. (Accessed 01.04.2011)
REITH, A. (1970): Faked Fossils of Primitive Man.
(Accessed 01.04.2011)

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