Science in Christian Perspective

 

 

Recent South Affrican Fossil Finds
Marie Fetzer
Instructor in Anthropology,
Wheaton College

From: JASA 3 (March 1951): 4-10.                                                            Comments

During the past three years there have been a number of newspaper reports and popular magazine write-ups of the "new missing linkn from South Africa, Two such articles may be' found in Life, March 21, 1949 and in the November 1949 issue of' Scientific American (Trooia, 1949).

The first discovery in this group of fossils goes back to 1925. A quarryman, blasting in a fossiliferous lime deposit near Taungs in West Transvaal, South Africa., came across a small skull which looked very human to him. The
skull was sent to Dr. Raymond Dart, an anatomist from the University of Witwatersrand in Johannesburg. Dart studied the skull$ reached the conclusion that it was that of an infant being intermediate between a higher ape and man, and early in 1925 published a paper describing this fossil,, which he names Australopithecus africanus. Eleven years later, in 1936, Dr. Robert Broom, who was working at the Transvaal Museum in Pretoria, resolved to look for an adult skull of this species. His search took him to some fossiliferous eaves at Sterkfontein in Central Transvaal., 40 miles from Johannesburg, where he found several fossil fragments that fitted together to form part of an adult skull. This he names Plestanthropus transvaalensis. During the next few years many other
skull fragments, isolated teet and parts of limb bones were found at this place and attributed to the Sterkfontein man. In 1938 Dr. Broom heard of a schoolboy from Kromdraai,, two miles east of Sterkfortein'. who had found some fossil bones and teeth at a weathered outcrop of fossil-bearing limestone. He located the youth and obtained some fragments of a palate bone, much of the left side of the face and the right side of the lower jaw with most of the teeth. On the basis of these bones, a new type was christened Paranthropus robustus, Collectively.,
these three have been known as the Australpithecinae. Fossil-hunting activity almost ceased in South Africa after tt4ss but at the close of the war it was resumed. Excavations during the past three years have added much material to this which has just been described.

Most of the recent work has been done at Sterkfontein., where many more bones attributed to Plealanthropus tranevaalensis have been Piund. In the early part of 1947 Dr. Broom described the crushed snout of apparently a young male with some beautiful teeth.." and "a fragment of the snout of a young child of about three years." Closely following this he described a nearly perfect adult skull of Plesianthropus tranevaalensis without the mandible and with the brain case broken across. About the middle of the year Dr. Broom described the nearly com
plete and fairly well-preserved lower jaw of a large middle-aged male and with it much of a humerus and scapula. In the fall he discovered a perfect pelvis, much of a femur, a tibia. some ribs and vertebrae, and parts of the skull very
badlycrushed and broken. In 1948,, another nearly complete, though broken., male mandible was found at Sterkfontein.

Finds attributed to the same genus as Australopithecus africanus., but given the new species name of prometheus, hence, Australopith prometheus, were found in the Makapansgat valley in Central Transvaal,
about 180 miles north of Sterkfontein, due to the searching of Professor Dart. The recovered bones of Australopithecus prometheus include a female occiput comprised of the major portion of the occipital bone, with most of the right margin of the foramen magnum., and the posterior third of each parietal, an adolescent male mandible with virtual ly perfect body and dentition, an almost complete left ilium, and the major portion of a right ischium of an adolescent, an isolated and warped right parietal bone of an infant,. and a craniofacial fragment of an adult.

Dr. Broom., in 1949, made further excavations in a cave on the farm Swartkrana one mile north of Swerkfontein, and found there what he terms remains of 8-10 individuals., including a practically complete but considerably crushed child skull of perhaps 7 years, two fairly complete but very badly crushed adult skulls, five lower jaws, four snouts, and a considerable number of isolated teeth. These individuals he calls Laranthropus crassidens.

A general survey of the South African material is given by Dr. Broom (Broom, 1950). It can be tabulated here as follows.

Australopithecus Africanus

Taungs                                     1925         Dart     front half of skull, top well preserved, brain cast, almost          complete facial skeleton, milk and permanent teeth

Plesianthromo tranavaalensis

Sterkfoutein                              1936        Broom   2/3 of a brain cast tape of skull 2 maxillae fragments of a brain case, which when restored yielded most of skull

                                                1936        Broom    other skull fragments isolated teeth parts of limb bones
                                                1947            "          2 snouts, isolated adolescent teeth ,adult skull, nearly complete mandible, humerus, scapula, pelvis, tibia, ribs, vertebrae, femur, mandible, with most of teeth


Paranthrpus robustus 

   Kromdraae                          1938         Broom    fragments of palate bone, much of left side of face, left side of skull base, fragments of am, band, and foot bones distal end of humerus

Australgithecus promethus

      Makapanpgat                   1947          Dart        female occiput, adolescent male mandible, left ilium, right parieal of an infant, adult cranio-facial fragment

Paranthropus crassidens

  Swartkrans            1947   Broom   skull of child
                                       5 mandibles
                                       4 snouts
                                       many isolated teeth

Detailed descriptions of the metric measurements and observations of anatomical landmarks characterizing each recovered bone are found in the literature cited in the bibliography of this paper. As this material is of a very technical nature, a series of quotations which will present general interpretation$ of these measurements and observations will be given.

Dr. Dart says concerning the Taungs material that because of the shape and pattern of the teeth, the size and proportions of the brain,, and shape of the forehead region2 Australopithecus africanus is midway between ape and man. Dr. Broom says of the Sterkrontein material thatthe brain is like that of a modern Ape, while the face bones are human in type and some of the limb bones suggest an upright posture. The Sterkfontein humerus, according to Broom,, is human in its size and structure. The scapula is not quite human., but also not anthropoid. The femur agrees in most characters with the femur of a small human being., and indicates thAt the creature walked erect. The Australopltheaus prometheus occiput has many human characteristics., and the pelvic Bones are similar to those of modern Bushmen. Dr. Dart (Dart,, 1949) says 11.... (they are) more closely related to man than****to apes. They are proto-human beings; and they are the most primitive hominids of whom we have knowledge." He quotes Dr. LeGros Clark, an English anatomist "They ' were hominids of small stature (probably similar in this respect to the pygmy races of present-day mankind), with brains not much larger relatively than those of the gorilla and chimpanzee, massive jaws showing many human features., a dentition fundamentally of human type, and limbs approximating in ,their structure and proportions to those of the Hominidae. They were evidently capable of standing and walking with an almost erect posture, and the hands and feet were relatively small and delicately built."

Dr.W. M. Krogmanj physical anthropologist from the University of Pennsylvania) has written his interpretation of the South African fossil material (Krogman, (1948). "What does our evidence on the Australopithecines add up to? It is this: that in the Pliocene periodabout seven million years ago, there lived a form that was intermediate between anthropoid and man. He had a brain near the anthropoid, a dentition practically human., and a general skeletal build well-adapted to the human upright position and locomotion. The Australopithecines fulfill almost every requirement of a real connecting form. Moreover they show that the rate of evolution differs in various parts of the body: thus dentition is ahead of long bones$ and long bones are ahead of brain.

"We are, certainly not sure of the precise evolutionary position of the ManApes. The problem is: were they A link in the direct line to man, or were they abortive offshoots of an attempt by an ape to make the grade to man's estate? The first alternative seems to me the more likely."

Dr. Broom (Broom, 1949) says "As the case stands at present, we have conclusive evidence that a family of higher primates which were practically human, but with relatively small brains,, lived in South Africa for probably hundreds of thousands of years ... But I personally do not think that the ape-men are arstbropoids. I believe that the human line split off from the anthropoids at least as early as the Lower Oligocene, perhaps 25 million years Ago, and that the nearest known type to mants remote Ancestor, is not A chimpanzeelike ape but the little foissil ape Propliopithems of Egypt. I suggest that the ape-men of South Africa came on a different line from the higher apes, and that one of them became the ancestor of Homo sapiens."

What then? Is this conclusive evidence concerning the origin of Homosapiens? Let us turn to other articles, to see what at least one other person has observed from this same material. Dr. William L. Straus, Jr. of Johns Hopkins University, has written several articles which have appeared in the American Journal of Physical Anthropology. In describing the humerus of Paranthropus robustus, Straus writes; (Kern and Straus, 1948) t "Both of these writers" (Broom and Dirt) have stated that this humeral fragment is basically human in morphology rather than anthropoid-ape.. and Broom has used it as a main prop in his argument that the Australopithecine forelimb was essentially similar to that of man and was not supported by the requisite comparisons, metric and otherwise, with other primates. Nor have adequate illustrations of the bone been published (strangely) no photographs have been made available). For this reason, particularly in view of the far-reaching and important claims that have been made respecting the signicance of this fragment., its careful re-study has been indicated."

Straus re-studied the humeral fragment., and concludes: "In. general however, Paranthropus ' bears a greater resemblance to the average chimpanzee than to the average man for in 14 of the 19 indices its value is closer to the mean of the anthropoid ape..,.In no circumstance can the fossil fragment be regarded as intermediate or !transitional! between the humeri of the anthropoida and that of man.

"The lower and of the humerus is basically so similar in man and the anthro.poid apes that this region is of extremely limited value in taxonomic and phylogenetic studies. It thus gives no real clue to general humeral structure~ much less to the structure sad usage of the rorellmb as 4 whole. There is no justification for the claims of Broom that the arms of the Australopithecines were not used for "walkng or climbing.

"We still lack the evidence necessary to conclude whether the forelimb of the AVetraldpithecines was that of a bipeds or a quadruped$ or a brachiator."

The same author writes the following concerning the femur of Plesianthropus transvaalensis,(Straus., 1949):

"Both Broom and Le Gros Clark have stressed the essentially manlike nature of this femoral fragment., which is quite small for that of a man yet within the size range of the Bushman femur (Le Gros Clark, 147b). Largely because of its presumed peculiarly hominid characters., both of these investigators have concluded that this bone belonged to an animal that was capable of standing and walking in the erect posture....

"That the fragmentary femur of Plesianthroeis in general strongly resembles the correspondixg part of that bone Un-man and differs markedly from those of the anthropoid apes, is not to be contested. The descriptions'and illustrations of Broom and Le Gros Clark amply affirm this conclusion. But It remains to be proven that the characters that it displays are peculiarly and exclusively hominid., and that such characters are necessarily indicative of ability to assume and maintain an erect, bipedal posture. While engaged in a comparative study of the femur., we have noted that in A number of points the Plesianthropus fragment is remarkably similar to the femora of Old World monkeys, an observation which has caused us to question the validity of the conclusions of Broom and Le Gros Clark. Neither of these workers seems to have included the monllceys within the scope of his investigations but rather to have limited Ids comparative studies to man and the anthropoids, particularly the great apes. A careful reconsideration of the nature of the Sterldmtein femur is therefore indicated. Unfortunately, no cast of this specimen is available to us for study. In Le Gros Clark's second paper (1947b), however,, there are sufficient data on several important points to enable us to make comparisons with our own observations on series of extant catarrhines-_ including man, anthropoid apes and monkeys--and thereby to assess the taxonomic and functional significance,of the major features of the fossil bone. Le Gros Clark deals especially with 5 femoral characteristics which will be discussed below.

"Both Broom and Le Gros Clark have claimed that the characters of the Plesianthroes femur are peculiarly hominid and definitely indicate that the anU%l was capable of assuming the erect, bipedal posture. In view of its equally close resemblance to.the femur of man and those of cercopithecid monkeys, however, it cannot be said to be more hominid than cercopithecid, nor to be more indicative of an erect, bipedal posture than of a pronogrades quadrupedal posture."

The age of this material is unknown from a quantitative point of view. There has been no adequate study of the sites by geologists~ which has appeared in print so far as this author has been able to determine. Dr.. Broom (Broom$ 1949) makes the following statements concerning his use of a field geologist:

"... our Historical Monuments Commission, which believes it has dictatorial rights to decide who is to be allowed to hunt for fossils, and how the work to to be done., intervened and warned me I would not be allowed to excavate except under conditions which I regarded as insulting. I was to be allowed to work only in collaboration with a competent, field geologist who was to be consulted whenever a blast was contemplated. To continue on such terms was impossible..,"

He stopped work at Sterkfontein for a short while, but later resumed it, working without the necessary permit from the Historical Monuments Commission. A valuable ' discovery was made, and concerning this Broom writes, (Broom. loc. cit.) "Of course the discovery was much too important to please the Historica1 Monuments Commission., especially as it had been made by defying them and by breaking the law, They sent a deputation to General Smuts protesting that in my excavations I paid no attention to stratigrapby and was destroying valuable historical evidence required for dating the specimens. Though there was no truth in the allegation, I was temporarily stopped# However, B. V. Loitdaard, professor of geology at Pretoria University, was invited to look into the matter and reported that there was no stratigraphy whatever where I had been working, and that I was doing no harm. So they had to allow me to continue,, though still under absurd conditions to which I pay no attention."

It should be noted that field work in human paleontology is not generally carried out in this fashion. Most of the human fossil material has been carefully documented both morphologically and chronologically. The sites of the Sirianthropus fossils, the Pithecanthropus fossils$ the Heidelberg fossil., and the Swancombe fossil, to mention A few, have been studied carefully by trained field geologists., and the findings are available in the literature.

From this survey of the literature we find that the excavations in South Africa have not been carried out in the strictest scientific procedure. We also find that there is disagreement by at least one other competent anatomist concern ing the diagnostic features used by Broom and Dart$ thus making definite decisions concerning the relation of these fossils to other higher primate fossils impossible at present. Further study must be made of these fossils from both a morphological and a chronological aspect, in order t4at their correct relation to other fossils may be ascertained.

Bibliography

Broom., R. (1949) "The Ape-Men.," Scientific American) November, p. 20.
Broom., R. (195o) "The Genera and species "of _the-South African Fossil Ape-Men," American Journal of Physical Anthropology Vol. 8 #1, March, P. 1.
Broom R. and Robinson, J. T. (1947a-"Jaw of the Male Sterkfontein Ape-Man,"
Broom Nature, Vol. 1169., p. 153.
Broom and Robinsonn, J.T. (1947b) "Further Remains of the Sterkfontein Ape-Man", Plesianthropus transvaalensis," Nature Vol. 160, P. 4309
Broom, R. and Robinson, J. T. (1949) "A new Mandible of the Ape-Man., Plestanthropus,
tranmalensiss" American Journal of Physical Anthropology, Vol. 7, #l March, p. 123..
Dart Raymond A., (1948a) "The Makapansgat Proto-human Australopithecus prometheuss" American Journal of Physical Anthropology, Vol. 6. #3 September, p.'259.
Dart Raymond A.,  (1948b) "The Adolescent Mandible of Australopecus prometheus." American Journal of Physical Anthropology Vol. 6, #4; Dec. p. 391.
Dart Raymond A., (1949a), "The Predatory Implement4l Technique of Australopithecus," American Journal of Physical Anthropology, Vol. 7., #1 March p. 1.
Dart Raymond A., (1949b), The Cranio~faoial Fragment of Auatralopithecus prometheus, American Journal of Physical Anthropology Vol. 7, #2s June, p. 187.
Dart Raymond A.,  (1949c) "The First Pelvic Bones of Australopithecus prometheus American Journal of Physical Anthropoloas Vol. 7, #2, June, P. 255.
Kerns Howardj M., Jr. and Straus, William L... Jr. (1~49) "The Femur of Plenianthropus tranavaalensisp" American Journal of Physical Anthropology, Vol 7, #1, March, p. 53.
Krogman, W. A. (1949) "Man-apes of South Africa: Recent Fossil Finds Named Plesianthropuss" Scientific American, Vol. 178,  May, P, 16,
Straus, William L. Jr. (l948), "The Humerus of Paranthropus  robustus," American Journal of Physical Anthropology, Vol. 6, #3, September, p. 285.

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Comments on RECENT SOUTH AFRICAN FOSSIL FINDS

Dr. Cowperthwaite

I would like to ask a question regarding the possibility of plastic deformation of bones throughout long periods of time. noticed that in the data you gave, the teeth which were small structures., were quite human in type, but that the long and thin bones-showed variations. I was wondering if it was possible for plastic
deformation to operate so that it would be difficult to determine the actual original shape of these bones.

Miss Fetzer

I am afraid I couldn't give you very much information on that because I don't know much about plastic deformation. I don't think so. Perhaps Dr. Maxwell might answer that more fully.

Dr. Maxwell

I can't answer.

Mr. Uuras Saarnivaara

As I remembers the profile of the ape is sometimes so similar to man that many times is almost impossible to distinguish them from one another so that the fact that some of the teeth of these South African Apes are somewhat hman does not necessarily mean anything because apes sometimes have teeth which look very much-like human teeth.

Dr. Bullock

Straus has produced a review article which was published in September 1949p in the Quarterly Review of Biology. It summarizes the situation that we have. The title of his article is "The Riddle of Man's Ancestry". It ends up with the conclusion that man's ancestry must remain for some time yet a riddle. In his paper he attempts to prove that man has not developed from the anthropoid line. You might be familiar with the branch family trees that are usually put up - man coming from an ape then man coming from a man ape and that Junction is retreating. Man has not even developed from a monkey., but man has developed from a prosimian. His arguments are not so much based on his recognition that man has come from an earlier monkey but that he has not come from the anthropoid ape.

Dr. Kulp

There certainly has been a lot of sloppy thinking in anthropology, Part of It has been due to the fact that in the modem scientific world a person in one field does not know anything in another field. Broom evidently has no knowledge or appreciation whatsoever for what geological data holds on these findings.