Fossil Men: Part III

By Jon Covey, B.A., MT(ASCP)
Edited by Anita Millen, M.D., M.P.H., M.A.

CORRECTION from Part II: The caption for the 2nd Frame in Fig. 5 is:

*"the comparison can also be made between female apes, australopithecines and late humans. This overemphasizes the similarity between australopithecines and apes."

In part two, we looked at some details concerning australopithecines, modern apes, and man. The upper palate of australopithecines most closely resembles the female chimpanzee, but there is not an exact correspondence. Australopithecines are not chimps. I remarked that evolutionists favor making a comparison between the male chimpanzee and the australopithecine to emphasize the differences between the two species and the australopithecine's similarity to humans. It is not certain if this is an attempted deception or an oversight by evolutionists. They might be assuming that the general public would arrive at the same conclusion Stephen Jay Gould did when he looked at the typical Frame 1 comparison and decided that "the palate of the Afar hominid [australopithecine] certainly says 'ape' to me." [Gould, p. 127] This tactic has not gone by unnoticed by other researchers.

Charles Oxnard, at the University of Western Australia, giving attention to the australopithecines, remarks that the investigations of Lord Zuckerman and his workers suggest that the australopithecines are merely fossil apes whose ape-like features had been de-emphasized by most investigators as they made their human-like assessments. [Oxnard, p. 123] He notes that in 1985 Wood presented a major paper indicating that his own new data show no australopithecine currently known could have been a human ancestor. [Wood, p. 41]

In 1975, just before the discovery of Lucy, Oxnard presented a paper based on multivariate statistical studies by himelf and others. He observed that most studies on australopithecines emphasized the similarities between them and modern man, ignoring the great dissimilarities. [Oxnard, p. 389, 1975] He noted that statements made by other investigators said that the australopithecines (A. africanus) were bipedal toolmakers; they walked upright and made tools.

In Fossils, Teeth, and Sex, after many more years of careful analyses, using multivariate statistical tools, he says that his new studies of teeth present a totally independent way of testing his conclusions and redefining certain controversies. The updated conclusions are:

"The first is that whenever we look at australopithecine post-cranial parts (Australopithecus africanus and A. robustus) using multivariate statistical tools, we conclude that they are not like humans in their structure. They are not even intermediate between humans and modern African apes. Indeed, they are more different from humans and African apes than humans and African apes are from each other.

"This conclusion was disputed for many years, it being generally asserted that the fragments were closest to humans in their form. There is now abundant evidence from many laboratories that this is not so. This first order conclusion is now generally accepted...

"The second order conclusion speaks to the functions implied by the structures of those fossil fragments. The earlier view was that bony structures similar to humans implied bipedality 'in the human manner'. Given that the bones are now recognized as being of a uniquely different structure than is found in either humans or African apes, it seems that these particular fossils may have possessed an equivalently unique set of functions. These may have included a form of bipedality biomechanically quite different from that of humans today, together with abilities for climbing trees different from those of any living ape....[see Phillips' remark below]

"The third order conclusion that comes from all this speaks to a phylogenetic position. Thus, a unique morphology implying a unique behaviour denies the view that has existed for many years: that the australopithecines were pre-human ancestors that were intermediate between us and some non-human, probably African ape-like ancestor. A unique morphology implying a unique behaviour may mean either (a) that the australopithecines were indeed on the human lineage, but as some unique mosaic form or (b), that the australopithecines were on some parallel lineage, a third branch in a radiation of forms that included also both humans and, separately, the African apes." [Oxnard, pp. x-xi, 1985]

Paleoanthropologist Dave Phillips says that A. afarensis has long upper limbs. The ratio of the arm length to the leg length is too large, approaching almost 85% of the leg length. The shape of the toe bones is ape-like. They are curved, having a divergence not seen in Homo, indicating that A. afarensis did not habitually walk upright. The legs are not like chimps'. To see these creatures in action would explain why the pelvis and lower limbs are the way they are.

High-resolution computed tomography, known as CT or Cat Scan, was used to scan the inner ear labyrinth of 53 humans, a few dozen apes consisting of pygmy chimps, chimps, gorillas, orangutans, and other species. They also scanned fossil humans (early Homo and H. erectus), Australopithecus and Paranthropus. Reporting in Nature, Wood and his coworkers made height and width measurements of the arc of each semicircular canal from the CT scans. From these measurements, they calculated the radius of the arc's curvature. Among the living specimens, they correlated the arc size of the three semicircular canals with the body mass. Taking body mass into account, modern humans have larger anterior and posterior canals and a smaller lateral canal than the great apes. According to Wood, Homo erectus is the earliest fossil hominid to demonstrate the modern human morphology of the inner ear. The dimensions of Australopithecus and Paranthropus inner ears resemble those of living great apes. Wood says,

"Modern human locomotor behaviour [walking] makes particular demands on the vestibular apparatus for it involves the maintenance of an upright body posture by balancing on very small areas of support."

In other words, humans have the correct inner ear configuration for obligatory upright walking, while apes, australopithecines, and Paranthropus do not.

Finally, Wood concludes his report by saying,

"This study demonstrates that the morphology of the bony labyrinth has the potential to provide information about both the locomotor behaviour and the phylogenetic relationships of early hominids." [Wood, 1994]

Last September, Randall Susman published a report in Science saying that scientists have generally assumed that at any one time the hominid with the largest brain was the toolmaker. From his study, he has proposed a test for humanlike precision grasping ("the enhanced ability to manipulate tools") and has applied it to australopithecines and early humans (Homo habilis, H. erectus, etc.). Susman's study was an analysis of the hand's functional morphology (shape) in humans, apes, and australopithecines. [Susman, p. 1570, 1994] There are anatomical features related to apes' power grasping and humans' precision grasping. Susman explains that J.R. Napier studied the functional morphology of primate hands and the relationship between the structure and the function of hands. Certain features of human hands are essential for the enhanced precision grasp. Partly, this has to do with the size and shape of the thumb bones, especially the pollical (thumb) metacarpal and partly it has to do with the associated muscles. Susman says that the apes have characteristically long, curved fingers with narrow fingertips, diminutive thumbs, and elongate pisiform (pea-shaped) bones in the palm. Humans have relatively short, straight fingers with broad fingertips and relatively long, stout thumbs with broad, fleshy tips. [Susman, p. 1571, 1994]

In his report, Susman made measurements of the thumb bones from 41 humans, 12 pigmy chimps, 49 common chimps, Homo sapiens neanderthalensis, Homo erectus, and Paranthropus robustus (Australopithecus). When they plotted the head width of the thumb bone (Metacarpal I) against the bone's length for humans and chimps, two clusters of data points developed. In further study, they calculated the ratio of these measurements for modern humans, Homo sapiens neanderthalensis, Homo erectus (SK-84), Paranthropus robustus (SKX 5020), and modern apes and noticed that two distinct categories developed: tool users and non-tool users. The measurements of A. afarensis clustered with the chimps, their ratios being about 25 percent. The two bones from H. erectus and P. robustus were in the human cluster.

This clearly puts Lucy and her ancestor, A. ramidus in the non-tool using, ape category. The announcement of A. ramidus' discovery appeared in the LA Times a few months ago. We now have the problem of P. robustus, previously classified as an australopithecine, possibly being a tool-using hominid. In his book Bones of Contention, Marvin Lubenow classes SKX-5020 with SK-84 as H. erectus but indicates that this is controversial among evolutionary authorities. [Lubenow, p. 123, 171] Both of these fossils are thumb bones from Swartkrans, South Africa. Trinkaus and Long examine Susman's reasoning and evidence, and then respond by saying that Susman's nonmorphological reasons for assigning these specimens to either species, including his suggestion that "simple statistical probability" indicates they should be assigned as indicated, are not adequate. Susman thought that because the site at which SKX 5020 was found contained more than 95% A. robustus remains and less than 5% Homo erectus remains, the bones were likelier to be A. robustus. Trinkaus and Long further state that Susman's morphological arguments fail to note any significant differences between the two specimens and conclude:

"The overall morphologies of both SK 84 and SKX 5020 largely conform to the pattern evident in modern and late archaic human MC-1s (MetacarpalI's—ed.)." [Trinkaus, p.420, 1989]

Water transported the specimens into a limestone cave in Swartkrans, resulting in a helter skelter deposition. It appears that no one can state conclusively to which species the thumb bones belong. However, Susman's findings on the thumbs and those of Wood on the inner ear further disqualify the australopithecines from human ancestral status. These studies refute the claim by Owen Lovejoy and Tim White that A. ramidus is our earliest ancestor and close to the "missing link" between humans and apes. [LA Times for 9/22/94]

In his 1975 paper, Oxnard made a revealing observation. He spoke about an ankle bone (talus) from East Rudolf found by Richard Leakey lying between layers that were dated at between 1.5 and 2.6 Myr, making it as old or older than the australopithecine ankle he studied for the paper. The important point he made is that this specimen seems to be much more like that of man as far as can be judged from photograph and descriptions, and further description and examination using multivariate statistical methods confirms that it is indeed similar to modern man and unlike the australopithecine specimens. [ Oxnard, p..394, 1975, Wood, p. 447, 1974]

Leakey found a skull dated at almost 3 Myr. The capacity of this skull was 800 cm3, possibly more. [Leakey] The capacity of some Homo erectus skulls are 900 cm3. This also is at the lower end of the modern Homo sapiens range which goes from 700 cm3 to 2200 cm3. [Molnar, p. 57] Skull capacity size does not correlate with intelligence; highly intelligent people have brain sizes at both extremes. Australopithecine skull capacity is in the range of 450 cm3 [Oxnard, p. 394, 1975] to about 650 cm3 shown on the chart displayed at the American Museum of Natural History in New York.

Oxnard cites the discovery of a four or more million years old human arm bone fragment from Kanapoi very similar to that of modern man [Patterson, 1967] and says that some of his demonstrations support that contention. [Oxnard, p. 394, 1975]

The above three items were fairly shocking news 20 years ago, but they fit in well with the tabulated pattern Lubenow establishes in his book. In it he shows that dates of fossils according to evolutionary reckoning, make H. erectus, H. habilis, and archaic H. sapiens contemporaneous with one another. If they lived at the same time, can one be the ancestor of the others?