Forbidden Archeology: The Hidden History of the Human Race

The H. habilis-H. erectus transition proposed by Johanson involves some rather extreme morphological changes, including a big change in size. Richard Leakey, applying normal human growth patterns, said that the Homo erectus boy, who was 5.6 feet tall, would probably have grown to over 6 feet tall as an adult. The female OH 62, on the other hand, was only about 3.25 feet tall, smaller than Lucy, who was about 3.5 feet tall.

How tall were the OH 62-type males? That is hard to say. Some presumably male Australopithecus afarensis individuals from the same Hadar, Ethiopia, site as Lucy may have been as much as 5 feet tall. On this basis, one might propose that an OH 62-type male might have been almost 5 feet tall. But, as we have seen, some workers say the size difference between the large and small Hadar specimens is too great to be accommodated within a single sexually dimorphic species. It seems likely, therefore, that the male companion to the 3.25-foot-tall OH 62 adult female was not much more than 4 feet tall. Altogether, an evolutionary leap from small, apelike OH 62 to big, humanlike KNM-WT 15000 in less than 200,000 years seems implausible.

Advocates of the much-debated punctuational model of evolution, however, can easily accept the transition. Unlike the traditional gradualists, punctuationalists assert that evolution proceeds by rapid episodes of change interrupted by long periods of stasis. The periods of change are so brief, say the punctuationalists, that intermediate forms are rarely preserved in the fossil record. Punctuationalism can, therefore, accommodate a variety of troublesome evolutionary anomalies, such as the habilis to erectus transition proposed by Johanson.

“The very small body size of the OH 62 individual,” said its discoverers, “suggests that views of human evolution positing incremental body size increase through time may be rooted in gradualistic preconceptions rather than fact” (Johanson et al. 1987, p. 209). But punctuational views may also be rooted in preconception rather than fact. The paleontological facts, considered in their entirety, suggest that various ape-man-like and humanlike beings, including some resembling modern humans, coexisted throughout the Pleistocene, and earlier.

In summary, the OH 62 specimen, seen as Homo habilis, delivers a triple blow to conventional ideas about human evolution. (1) OH 62 shatters the prevailing humanlike portrayal of Homo habilis, as presented in book and magazine illustrations, television shows, and museum exhibits. (2) The primitive morphology of OH 62 raises questions about the taxonomic status of very humanlike postcranial bones, such as the ER 1481 femur, which have been attributed to Homo habilis. To what kind of hominid should they now be assigned? It is possible they belonged to an anatomically modern human species that coexisted with Homo habilis, the australopithecines, and Homo erectus around 2 million years ago in Africa. (3) The size and geological age of OH 62 make the conventionally accepted evolutionary transition from Homo habilis to Homo erectus less plausible. Of course, if one were to classify OH 62 as an australopithecine that would resolve some of these difficulties.

11.7.3 Conflicting Assessments of Other Homo Habilis Fossils

It was not only new evidence such as OH 62 that challenged the long-accepted picture of Homo habilis. Previously discovered fossil evidence relating to Homo habilis, originally interpreted by some authorities as very humanlike, was later characterized by others as quite apelike.

11.7.3.1 The OH 8 Foot

As mentioned earlier (Section 11.4.2), a fairly complete foot skeleton, labeled OH 8, was found in Bed I at Olduvai Gorge. Dated at 1.7 million years, the OH 8 foot was associated with other fossils classified by L. Leakey as Homo habilis (OH 7) and was also attributed to this species (Lewis 1980, pp. 275, 290).

M. H. Day and J. R. Napier (1964) said the OH 8 foot very much resembled that of Homo sapiens, thus contributing to the overall humanlike picture of Homo habilis. According to Day and Napier, the OH 8 foot showed that Homo habilis walked upright.

But O. J. Lewis (1980, p. 291), anatomist at St. Bartholomew’s Hospital Medical College in London, wrote: “The attribution of these remains to the taxon Homo has been a source of controversy.” He showed the functional morphology of the OH 8 foot was more like that of chimpanzees and gorillas (Table 11.4).

TABLE 11.4

 

1. Articulations between the metatarsals “are like the chimpanzee” ( p. 294).

2. Ankle joint surfaces “retain the apelike form” ( p. 291).