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No Business Like Bone Business

Paleoanthropology continues to impress with its willingness to draw the most far-reaching conclusions from the most pathetically minute evidence, in the form of shattered, nearly pulverized bone fragments. The news today tells an engaging story of a trio of hominid species (H. erectus, H. habilis, H. rudolfensis) living alongside each other in Africa less than 2 million years ago.

At the center of attention is a reconstructed skull, joining a newly recovered lower jaw with a cranium that was found in 1972.

MSNBC reports:

"Two species of the genus Homo, our own genus, lived alongside our direct ancestor, Homo erectus, nearly 2 million years ago," researcher Meave Leakey at the Turkana Basin Institute in Nairobi, Kenya, told LiveScience.

A skull known as KNM-ER 1470, found in 1972 in Kenya, was at the center of the debate over the number of species of early Homo living nearly 2 million years ago. It had a larger brain and a flatter face than H. habilis, leading some researchers to declare it a distinct species they dubbed Homo rudolfensis.

However, making comparisons between these fossils was difficult, because no single purported H. rudolfensis specimen contained both the face and the lower jaw, details needed to see if it was indeed separate from H. habilis. Any supposed differences between H. habilis and H. rudolfensis might, for instance, have been due to variations between the sexes of a single species.

The newly discovered face and lower-jaw fossils, uncovered within a radius of just more than 6 miles (10 kilometers) from where KNM-ER 1470 was unearthed, now suggest that KNM-ER 1470 and the novel finds are indeed members of a distinct species of early Homo that stands out from others with its uniquely built face.

Well, maybe or maybe not. Skull 1470 has long been notorious for its ability to assume different shapes depending on how it is reconstructed. Below is a relevant excerpt from Jonathan Wells's Icons of Evolution (2000).
One famous fossil skull, discovered in 1972 in northern Kenya, changed its appearance dramatically depending on how the upper jaw was connected to the rest of the cranium. Roger Lewin recounts an occasion when paleoanthropologists Alan Walker, Michael Day, and Richard Leakey were studying the two sections of "skull 1470." According to Lewin, Walker said: "You could hold the [upper jaw] forward, and give it a long face, or you could tuck it in, making the face short.... How you held it really depended on your preconceptions. It was very interesting watching what people did with it." Lewin reports that Leakey recalled the incident, too: Yes. If you held it one way, it looked like one thing; if you held it another, it looked like something else."1

Just recently, National Geographic magazine commissioned four artists to reconstruct a female figure from casts of seven fossil bones thought to be from the same species as skull 1470. One artist drew a creature whose forehead is missing and whose jaws look vaguely like those of a beaked dinosaur. Another artist drew a rather good-looking modern African-American woman with unusually long arms. A third drew a somewhat scrawny female with arms like a gorilla and a face like a Hollywood werewolf. And a fourth drew a figure covered with body hair and climbing a tree, with beady eyes that
glare out from under a heavy, gorilla-like brow.2

This remarkable set of drawings shows clearly how a single set of fossil bones can be reconstructed in a variety of ways.

References:

(1) On the variable appearance of skull 1470, see Roger Lewin, Bones of Contention, Second Edition (Chicago: The University of Chicago Press, 1997), p. 160; see also Ian Tattersall, The Fossil Trail: How We Know What We Think We Know About Human Evolution (New York: Oxford University Press, 1995), p. 133.

(2) The drawings of Homo habilis by four different artists are in "Behind the Scenes," National Geographic 197 (March, 2000): 140. The drawings are actually on an unnumbered page, buried among the advertisements at the end of the issue; the page number cited here was obtained by extrapolating from the last numbered page.