Forbidden Archeology: The Hidden History of the Human Race

In Leakey’s opinion, the major problem with the standard view of human origins was that it resulted in a progression that appeared to violate evolutionary principles. “Australopithecinae or ‘near-men’ show a number of characters which very strongly suggest over-specialization in directions which did not lead towards man,” said Leakey (1960d, p. 184). “The very peculiar flattening of the face, the raising of the eye sockets high above the level of the root of the nose, and the shape of the external orbital angles are among such specializations, as is also the forward position of the root of the cheek-bone process.”

Leakey (1960c, p. 212) also stated: “there are those who still hold that Peking man and Java man should be listed as direct ancestors of Homo sapiens, with Neanderthal and Solo types as intermediate forms, but I cannot support this interpretation, which implies too great a measure of reversal of specialization.” Some of Leakey’s contemporaries assumed the earliest hominids would have features reminiscent of modern apes. According to this view, the path of human evolution, proceeding through the australopithecines and Homo erectus, involves a progressive diminution of these primitive apelike features. According to Leakey (1960d), this idea is incorrect.

Certain features of modern apes, such as large brow ridges, are not primitive, said Leakey, but are instead fairly recent specializations. Proconsul, an Early Miocene African ape thought to be at the very root of the human line, did not have large brow ridges. “There is no trace whatsoever of a ridge of bone over the eyes, separating the brain-case from the face,” wrote Leakey (1960d, p. 175).

Modern humans, with their small brow ridges, according to Leakey, preserve the primitive condition found in the Miocene apes. Australopithecus, Homo erectus, and the Neanderthals, with their large brow ridges, depart, like the modern apes, from this primitive condition. The now-dominant evolutionary progression thus involves an evolutionary reversal that Leakey thought unlikely. Miocene apes with no brow ridges give rise to early hominids with heavy brow ridges, and these hominids in turn give rise to modern humans, with small brow ridges. Furthermore, the Miocene apes like Proconsul have thin skulls, while the australopithecines, Homo erectus, and the Neanderthals have relatively thick skulls. Modern humans have thin skulls, implying another evolutionary reversal.

The advocates of punctuated equilibrium in evolution have a response to Leakey, namely that such reversals can be expected (Stanley 1981, p. 155). One of the great advantages of the punctuated equilibrium theory, which holds that speciation occurs not gradually over long periods of time but in rapid bursts, is that it allows advocates of evolution to easily explain away all kinds of contradictions found in the fossil record.

Apart from size, the physical structure of modern human brow ridges is different from that of other hominids. “The brow-ridge over each eye is made up of two component parts in Homo sapiens ,” wrote Leakey (1960d, p. 164). “One part in each case starts just above the nose and extends sideways and slightly upwards to overlap the second part, which, on either side, starts at the extreme edge to right and left of the eye-socket respectively, and extends inwards and slightly downwards. Thus, above the center of each eye-socket, there is an overlap of the two elements.” In Neanderthal, Homo erectus, and Australopithecus, the large brow ridges are most often composed of a single barlike mass of bone running horizontally over the eye sockets. To Leakey (1960d, p. 165), the presence of such barlike brow ridges “suggested not an ancestral stage in human evolution but a side branch that has become more specialized, in this respect, than any Homo sapiens type.”

In addition to features found in the earliest presumed human ancestors (the Miocene apes such as Proconsul ), modern humans also have, said Leakey, other specializations that distinguish them from Homo erectus and Australopithecus.

For example, the jaw of modern Homo sapiens has a chin eminence, which Leakey (1960d, p. 168) described as a “bony buttress on the front of the middle line of the jaw.” Living apes do not have a true chin eminence, and neither do Homo erectus and Australopithecus.