The existence of fossils in sequential geological deposits poses serious problems for creationists who do not acknowledge evolutionary patterns in the paleontological record. Archaeopteryx, the transitional reptile-bird form, is one of the most outstanding examples of a major evolutionary transition, and the fossil sequences for horses (Monroe, 1985), elephants, and even horned dinosaurs (Edwords, 1982) are examples of well-documented evolutionary lineages. However, the fossil evidence pertaining to human evolution and the origin of the hominids in general presents special difficulties for creationists.
Australopithecine fossils provide an especially good example of two of the creationists' central concerns: the obvious biological similarity between humans and other organisms (particularly the apes) and the existence of creatures with a distinctive (perhaps disturbing or distressing to creationists) combination of apelike and human-like features. Creationist claims to the contrary, the hominid status of the australopithecines is quite justified, not seriously open to question today, and of special importance to the question of the evolutionary origin of humans.
Furthermore, even though I shall emphasize the physical similarities between the australopithecines and later hominid forms, it is important to understand that their taxonomic classification as hominids is based not merely upon physical similarities but upon their inferred evolutionary affinities with later hominids as well. Because of the evolutionary perspective of modern biology and systematics (Eckhardt, 1979; Wolpoff, 1980), the inclusion of the australopithecines in the family Hominidae is based upon the fact that they are in the right geographical place (Africa) at the right time (after the earlier Miocene dryopithecines and ramapithecines and before the later Homo erectus) as well as upon their degree of structural similarity to Homo erectus and Homo sapiens.
An objection may be raised that the inherent evolutionary perspective of modern taxonomic classification provides an a priori basis for creationists to criticize and reject outright the conclusion that the australopithecines are hominids and the evolutionary significance of this fact. After all, creationists might argue, since any such evolutionary-biased classification of these fossils is based upon the two fundamental errors that undermine all modern biology, if not most of science—namely, the great antiquity of the world and the evolutionary development of all the life forms on this planet—then the classification is meaningless. Furthermore, since modern geological dating methods are supposedly faulty, as "young-earthers" allege, and there is no compelling fossil data to support the claims of evolutionary kinship between any organisms (it's all those gaps, you know), then the australopithecines can hardly be considered convincing evidence of any long-past human evolutionary ancestors because no such ancestral forms can even exist. Thus, creationists could conclude that they need not even concern themselves with any discussion of the australopithecines; at best, it is all a big mistake, or, at worst, merely another effort to deny and obscure the real story of the origin of humans and the world.
Dismissing the evidence or misinterpreting it, however, does not answer the question of what the australopithecines are. Their geological antiquity aside, and simply from the perspective of comparative anatomy, the combination of features evident in the australopithecines would present significant problems for creationists even if there were no evolutionary interpretations of their status. We can only wonder how Carolus Linneaus, the eighteenth-century "father" of modern taxonomy and a believer in special creation, would have classified the australopithecines when he only reluctantly excluded the "ape" from the genus Homo, even though he acknowledged his inability to find a "character" to justify any separation of the two (Green, 1959:184-185).
Consider the creationists' dilemma: the more humanlike the australopithecines are, the more difficult it is to maintain the special uniqueness of "man." On the other hand, the more apelike the australopithecines are, the more apelike modern humans are (because of the array of attributes we share with the australopithecines) and, again, the less unique and less special is "man." From either perspective, the australopithecines make trouble for creationists.
Davis A. Young, an acknowledged biblically based scholar believing in the special creation of humans (in the form of Adam and Eve), has considered some of the problems posed by fossil evidence of human evolution for certain Christian beliefs (Young, 1977, 1982a, 1982b). His thoughtful discussion of the hominid fossil record is in sharp contrast to that of the three creationist authors considered here. (Two of Young's books, Creation and the Flood and Christianity and the Age of the Earth, also happen to be two of the most severe, scholarly, and insightful critiques of the young earth model of "scientific creationism" yet published.) The questions about the meaning of the human fossil evidence that he raises reveal some of the difficulties facing creationists:
What is the Bible-believing scientist to do with these [australopithecine to Neanderthal] fossils? Can he tell where in time among this group of fossils the creation of Adam took place? Can he tell which of these ancient manlike fossils represent genuine man?[1977:151]
In a May 1982 article in Eternity, Young acknowledges the possibility of a human evolutionary sequence extending back to the australopithecines but nevertheless concludes:
The biblical record clearly demands the special intervention of God in the origin of man. . . . Evolution cannot account for man as God's image-bearer, nor can it account for our sinful estate. It seems to me that the present scientific theory of evolution, apart from the question of the origin of man, is not necessarily anti-Christian or unbiblical.[1982b:19; emphasis added]
Although not the topic of this paper, the theological and biblical problems raised by the evidence for the evolutionary origin of humans is of the utmost importance for many thoughtful people.
Nonspecialists may easily be confused by the way such names as australopithecine, Australopithecus, hominid, Hominidae, pongid, Pongidae, Homo, and even human are used by various authors. It is necessary to have some understanding of what these terms mean and how they are formally used (and misused) before considering some specific creationist writings on the australopithecines.
Since first introduced by Carolus Linnaeus in the 1700s, standard taxonomic practice has assigned a genus and a species designation to each distinctive organism studied. Examples are Homo sapiens for modern humans, Pan troglodytes for the common chimpanzee, Pan paniscus for the pygmy chimpanzee, Gorilla gorilla for the gorilla, and Pongo pygmaeus for the orangutan. Genus-level names are capitalized, species-level names are not, and both names are italicized or underlined in print.
Biological species are generally conceptualized as "groups of interbreeding natural populations that are reproductively isolated from other such groups" (Mayr, 1970:12). Occasional interbreeding between members of related, but different, species—such as lions with tigers or horses with zebras—does not invalidate the species concept in general nor the legitimacy of taxonomically distinguishing between the particular forms involved. This is because such infrequent mating is in contrast to the usual pattern of members of the same species mating only with others of the same species and because the "hybrid" almost never constitutes a natural population.
Species are also usually distinctive in terms of their anatomy, physiology, habitat, reproductive patterns, diet, geographical range, and other features. Physical differences are especially useful in classifying the millions of extinct species. Reproductive incompatibility is not always ascertainable, since dead specimens are no longer reproductively active!
Species that share more features in common with one another than they do with other species are grouped collectively into a common genus (for example, Pan troglodytes and Pan paniscus or Homo sapiens, Homo erectus, and Homo habilis). Genera (plural of genus) sharing features that serve to distinguish them from other genera are grouped into still broader categories such as families (for example, Pan, Gorilla, and Pongo in the family Pongidae; Homo and Australopithecus in the family Hominidae). The common terms pongid and hominid are used extensively to distinguish between characteristics of the great apes and those of modern humans and their fossil antecedents. For example, in an evolutionary perspective, hominid features of earlier forms (either genera or species) may be manifested more often in different or primitive fashion than they are in later forms. But it is the distinctive pattern of these features that is the basis for making the taxonomic distinctions between hominids and other organisms.
It is sometimes difficult to make decisions about taxonomic placement of living forms, and it can be even more difficult when dealing with fossil specimens. But problems in applying the principles of taxonomy no more invalidate the endeavor than do problems in accurately translating ancient Hebrew, Aramaic, and Greek documents invalidate the efforts of scholars to understand biblical texts. Scholarly disputes among specialists in both endeavors are to be expected and constitute a natural part of the process of achieving consensus judgments about particular problems.
Problems in Taxonomic and Nontaxonomic Usage
Neither ape nor human are formal taxonomic terms. While human traditionally refers to living and recent members of Homo sapiens, it becomes increasingly difficult to apply this term unequivocally to such forms as Neandertal, Homo erectus, Homo habilis, and the australopithecines. Human does not necessarily mean the same thing as Homo or hominid. In formal discussions of fossil specimens, it is probably best to minimize one's usage of this term in order to avoid leaving unjustified impressions in the reader's mind. A good example is the use of the term human when describing all of the different australopithecine forms, because this may well leave the reader with the idea that all of these forms are ancestral to modern humans when this is clearly not the case.
The genus name Australopithecus does not necessarily mean the same thing as the informal term australopithecine, frequently used in a collective sense to refer to all of the non-Homo erectus African hominid fossils of Pliocene and early Pleistocene age. When used in such a fashion, to some authors australopithecine actually refers to an evolutionary "grade" of features shared because of a common level of organization (Wolpoff, 1980:34, 131, and 180) or to a "clade" or groups of species having a single common ancestor (Jolly and Plog, 1982:83 and 193-194). In recent years, a new convention has emerged that simply entails using some variation of the phrase Pliocene-Pleistocene hominids to refer to these fossil forms (Eckhardt, 1979; Kennedy, 1980; Nelson and Jurmain, 1982; Poirier, 1981; Wolpoff, 1980).
How Many Fossils?
If knowledge of the number and nature of australopithecine fossil remains were based solely on creationist sources, then one might well be left with the impression that there are only a handful of fossils that have been discovered and that even these are not especially informative. Henry M. Morris exemplifies this impression succinctly: "In many cases (e.g., Ramapithecus, Australopithecus [sic], etc.) the very fragmentary evidence is quite consistent with the view that such creatures were merely extinct species of apes" (1978:46). Use of the term fragmentary here conveys the double impression that the fossils themselves are in broken condition (frequently, but not entirely, true) and that there are hardly even enough specimens to bother considering, let alone use as a basis for some wild and imaginary evolutionary schemes (not nearly the true state of affairs). Morris and Gary Parker reemphasize the plausibility of these fossil forms being apes: "The name Australopithecus means `southern ape,' and there's a good chance that's just what they are" (1982:119).
Just how many of these fossils have been recovered to date? Let's look at the evidence.
In their 1982 physical anthropology textbook, Harry Nelson and Robert Jurmain tabulate the number of specimens. For the five South African sites alone there are some 175 cranial remains, 769 teeth, and 78 postcranial (from the neck down) remains for a total collection of 1,022 items representing some 121 to 157 individuals (1982:393). Elsewhere in their text, they tally data from the East African fossil localities in Tanzania, Ethiopia, and Kenya—a minimum of 475 specimens (teeth and bones) representing at least 100 to 200 individuals (1982: 430-431). Similar data can be found in Eckhardt (1979:460-467) and Kennedy (1980: chapter 7) and can be obtained from the numerous original scientific reports of field investigators. More specimens are always desirable (and, in fact, are being unearthed regularly), but it is evident that we are not dealing with a mere handful of fossils.
Pongid or Hominid?
To put it as bluntly as possible, exhaustive study and analysis of these hundreds of fossil specimens have resulted in one unequivocal conclusion: the australopithecines are not apes; they are hominids. But what exactly is the basis for this conclusion? What features does one examine in order to ascertain whether a given specimen (fossil or not) is a pongid or a hominid? Studies of present-day forms reveal some obvious, and not so obvious, differences between living representatives of these two groups. These differences can conveniently be grouped into three broad complexes: locomotion; face, teeth, and jaws; and brain size and function.
In terms of locomotion, pongids possess the anatomy for brachiation—swinging or hanging in the trees in a vertical position with the arms extended over the head. This anatomy is modifiable for extensive terrestrial locomotion (at least in the case of Pan and Gorilla) into the "knuckle-walking" pattern of semi-erectness. The occasional bipedalism exhibited by these forms does not contradict their fundamental brachiating anatomical attributes. Among these are longer arms than legs, naturally curved fingers with a short thumb, a narrow pelvis, and an opposable big toe to facilitate the grasping of branches. This brachiating anatomy and pattern of locomotion is in stark contrast to the fully erect bipedalism of modern Homo who possess longer legs than arms, a precision grip using effective opposable thumbs, a wide and shallow pelvis with broad iliac blades, expanded sacral and lumbar vertebral attachments to help support the erect upper body, a strong and supportive yet fully extendable knee joint, and a foot with strong arches and a nonopposable big toe for both powerful striding push-off and support of the entire body. Also, the more forward position of the foramen magnum, or large hole in the base of the skull, reflects the fully erect posture of humans in contrast to the more rearward position of this opening in pongid skulls; hominid skulls rest atop the vertebral column.
With regard to the second complex—face, teeth, and jaws—living pongids have an obviously protruding lower face while human faces are essentially flat. The front teeth of the pongids are notable for having broad, forward-slanting incisors and fairly long, projecting canines. Modern humans have narrow, vertically implanted incisors and short canines. Whereas the back teeth of pongids are comparatively large and seldom worn down flat in a side-to-side fashion, smaller and flat-worn molars are characteristic of most pre-agricultural humans. The jaws of pongids are heavy and possess powerful chewing muscles frequently associated with prominent bony attachment sites such as the sagittal crest along the top of the skull. Humans have less powerful muscles and lack such powerful bony protrusions.
Finally, pongid brains are absolutely smaller than brains of modern humans (on the order of about one-third to just less than one-half) as well as being relatively smaller compared to overall body size.
Relying upon these (and many other) criteria to assess the taxonomic and evolutionary status of the australopithecines, scholars have reached the consensus view that they were definitely hominids, although not identical to modern humans. To quote Wolpoff:
What is typically hominid is not necessarily the same as what is typically human today. Some features that have characterized most of hominid evolution do not appear in living people. . . . The first members of our lineage may be more hominid-like than their pongid contemporaries without necessarily being more like living humans.
The significant point to emphasize with regard to the australopithecines is that, while they are distinctive in certain respects, they exhibit the combination of features that distinguishes them from any known living or extinct pongid and that conforms to the fundamental pattern of features that is seen in later hominid forms.
Thus, despite some pongidlike features—such as molar tooth size, small absolute brain size (compared to Homo erectus and Homo sapiens), powerful chewing complex with occasional slight sagittal crests, and relatively large protruding faces—the australopithecines are still classified as hominids (but not as Homo sapiens or even Homo erectus) since they manifest the overall pattern characteristic of this taxonomic group.
Among the more important hominid attributes of the australopithecines are a large brain relative to overall body size, reduced canine size, flat-worn molars, and numerous indications of the adoption of fully erect posture and bipedalism (although not necessarily in a fashion identical to modern Homo). In addition to these characteristics, australopithecines share with other hominids a strengthened lower back, a pelvis with a broad ilium, and virtually all of the other pelvic, hip, knee, ankle, and foot modifications associated with erect bipedalism. These features and others are described and discussed in any number of anthropological works (for example, Howell, 1978; Jolly and Plog, 1982; Kennedy, 1980; Poirier, 1981; Wolpoff, 1980). The hominid status of the australopithecines has been so thoroughly substantiated by this time that a statement like that of Morris that they can be considered "merely extinct species of apes" (1978:46) suggests a profound ignorance of the wealth of data now available.
How Many Forms?
Paleoanthropologists today agree that more than one form of Pliocene-early Pleistocene hominid existed. While there is not universal agreement about the number of species (or even genera) recognized, there is widespread consensus that two basic forms are involved: the gracile and the robust, based upon overall size and degree of body and chewing musculature (see Figures 1 and 2, center book). The robust forms are considered to be somewhat more specialized and less likely to be directly ancestral to later hominids like Homo erectus. The robust forms also appear to have consisted of an earlier and a later species. They are usually placed in the genus Australopithecus but may still occasionally be referred to as Paranthropus. The most common species designations are Australopithecus robustus and Australopithecus boisei. The fossil evidence for these robust species dates from about 2.6 to 1 million years ago (Boaz, 1979:76; Johanson and Edey, 1981:284; Shipman, 1986). Some of the earlier robust forms may or may not have been contemporaries with some of the gracile forms (usually designated Australopithecus africanus) depending upon one's assessment of the possible age of some specimens and sites, as well as the classification of some specimens. At least one interpretation considers the gracile forms as being ancestral to the robust forms (Wolpoff, 1980).
It does appear, however, that there existed a distinctly earlier, more primitive australopithecine form (more nearly gracile than robust in appearance) which is quite possibly ancestral to both the later gracile and robust species regardless of whether the later graciles are, in turn, ancestral to the robust forms. This earlier, more primitive australopithecine dates from approximately 4 to 3 million years ago and has been classified as Australopithecus afarensis by Donald Johanson and Timothy White (1979). This species includes fossils recovered from Hadar in Ethiopia and Laetoli in Tanzania. At least one dissenter does not think that all of the fossils Johanson and White have assigned to Australopithecus afarensis should be so assigned (Leakey, 1981:70). Australopithecus afarensis is characterized by its erect and bipedal form of knee and pelvis and a distinctly pongidlike skull.
The final form to be considered is Homo habilis. Generally accepted specimens assigned to this earliest species of our own genus date from around 2.1 to 1.5 million years ago. Our understanding of the evolutionary relationship existing between Homo habilis and both the gracile and robust australopithecines is incomplete. While all of the most widely accepted Homo habilis fossils are contemporaneous with many earlier robust australopithecines (and, thus, evolutionary "cousins"), the relationship between Homo habilis and the gracile form is less clear. While Homo habilis resembles the gracile form somewhat in terms of overall body size and musculature, it tends to have a larger braincase and may have had a slightly different form of bipedal locomotion (Jolly and Plog, 1982:220; Kennedy 1980:243). Homo habilis is usually considered descended from some earlier australopithecine form, most likely Australopithecus afarensis ultimately but from Australopithecus africanus as an intermediate link (Johanson and Edey, 1981:284; Jolly and Plog, 1982:189, 207, 209; Wolpoff, 1980:155, 165, 181-182). Homo habilis, in turn, is considered the most likely ancestor of Homo erectus who appears around 1.5 million years ago near Lake Turkana in Kenya. Homo erectus coexisted with the last of the surviving robust australopithecines, which disappear from the fossil record at around 1 million years ago. There is no apparent evidence of either Homo habilis or gracile Australopithecus coexisting with Homo erectus.
Creationist Criticisms of the Australopithecines
With this brief background, let us now turn to some additional creationist writings dealing with the australopithecines. The claims of Morris (1978) and Morris and Parker (1982) that the australopithecines may be nothing more than apes have already been discussed. Consider now this statement from Robert Kofahl's Handy Dandy Evolution Refuter: "Australopithecus has now gone completely down the drain as far as human ancestry is concerned" (1980:78).
The first difficulty the reader should have with this assertion, of course, is that it is not at all clear to which forms Kofahl is referring. If he is referring to the robust and later gracile forms, he is in technical agreement with the majority of paleoanthropologists, at least in the sense of either of these forms being directly ancestral to the genus Homo. But what Kofahl does not say is that many (if not most) paleoanthropologists think that the earliest species of the genus Homo now usually recognized, Homo habilis, is quite likely descended from some form of gracile Australopithecus earlier than 2.5 million years ago. The most likely candidate, as already mentioned, is Australopithecus afarensis. Thus, Kofahl is, at best, premature and probably quite incorrect in dismissing Australopithecus from the ancestry of the genus Homo and, subsequently, modern humans. He falls into the "missing link" trap, assuming that an individual fossil is the transitional form; such reasoning would require one to rule oneself out of the hominid line if a great-grandparent were unknown despite a clear family tree filled with great-aunts, great-uncles, grandparents, parents, uncles, aunts, and cousins.
Presumably to show that the allegedly older and ancestral Australopithecus is actually younger than its supposed descendants, Kofahl makes reference to both "a find which was more human and . . . dated a million years older" than Australopithecus and "evidence of a human living area [at Olduvai Gorge] at a lower level than the Australopithecus remains" (1980:77). The first reference is to the KNM-ER-1470 cranium found by Richard Leakey's team near Lake Turkana and classified as Homo habilis. The second reference is to the Leakeys' Olduvai Gorge discovery of site DK1, an apparent campsite with evidence of artificially placed heavy stones similar to stones used until recent times by hunter-gatherers to weigh down the edges of animal skin shelter tents or windbreaks. The structure and tools there have been attributed to Homo habilis, bones of which have been found at sites in the gorge nearby. Kofahl does not mention or discuss the Homo habilis taxon, so one can only wonder if his use of the term human here refers to this early species of Homo. (In any case, the "million years older" age assigned to the 1470 specimen has been revised downward to approximately 2 million years, contemporaneous with the Olduvai Gorge specimens of this species.)
Given that Homo habilis had already been rather extensively documented by the time Kofahl wrote (1977 and 1980), his failure to include any formal discussion of it in his treatment of the australopithecines is surprising, to say the least. By ignoring it, of course, he need not inform his readers that this form is usually considered ancestral to later species of Homo. Consequently, his rhetorical question, "Now who will step up to be the next candidate [for human ancestry]?" (1980:78) rings hollow. His less than technical reference to Australopithecus raving "gone completely down the drain as far as human ancestry is concerned," implying the total irrelevance of this genus or grade for our understanding of human evolutionary origins, is disingenuous. Our understanding of the origin of the genus Homo in particular and the family Hominidae in general would not have been possible without knowledge of the nature and variation in the genus Australopithecus.
But Kofahl is not done with his discussion of Pliocene hominids. Elsewhere he writes: "Both [Richard] Leaky [sic] and the Taieb-Joranson team have claimed that their fossil finds make all previous theories of human evolution obsolete, but they have little to offer as substitute theories" (1980:78-79). Such a statement not only does gross injustice to the work of these scholars, it also indicates a profound misunderstanding or misreading of their writings. The fact that this 1980 edition of Kofahl's 1977 work includes references only to 1971 and 1973 articles by Leakey and two news accounts of Taieb's and Johanson's work published in 1974 and 1976 reinforces the conclusion that Kofahl was, at best, ignorant of the numerous published materials that already dealt with these discoveries even by 1977, let alone 1980. Kofahl's claim that evolutionists have "little to offer as substitute theories" is ludicrous. Competing interpretations are numerous—a sign of a healthy science—but even the most skeptical analysts of the swarm of australopithecine-habiline fossils grant that directly or indirectly these fossils represent the first hominids.
But what is Kofahl's basis for claiming that Australopithecus has disappeared down the drain of human ancestry in the first place? In the writings of Kofahl and in Morris and Parker (1982:121-124), the work of Charles E. Oxnard is cited. Let's examine what Oxnard has said and then consider how, in particular, Morris and Parker seriously misquote him.
Charles Oxnard is an anatomist who has utilized various statistical techniques to analyze and compare the form and function of bones from both fossil and living species. The results of his work that are pertinent to this discussion are those regarding the evolutionary status of the australopithecines. Succinctly put, he does not think that the australopithecines are in the evolutionary lineage leading directly to the appearance of Homo erectus and Homo sapiens. (He also does not think that Homo habilis is a valid taxonomic category.) His analyses were based upon selected fossil specimens, including a pelvis and scapula from Sterkfontein, a talus (large ankle bone) from Kromdraai, and four specimens from Olduvai Gorge: a clavicle, talus, proximal hand phalanx, and terminal toe phalanx.
His studies suggest to him that most of these australopithecine specimens are uniquely different from both living apes (and in some cases the Miocene-age ape form Proconsul) and modern humans (Oxnard, 1973:165, 168; 1979:273-274). After concluding that "both of these regions [hindlimb and forelimb] present clear evidence of functions that differ from those of modern man" (1973:168), Oxnard goes on to state that "we may now be able to search for the actual nature of morphologies and functions relating to a species that is becoming somewhat similar to man, but that is clearly not there yet" (1973:168). In his 1979 article, cited by Morris and Parker, Oxnard writes, "It is far more likely that the genus Homo is much older than currently believed and that the australopithecines of Olduvai and Sterkfontein represent only parallel evolutionary remnants" (1979:274). Both this quote and the second one, cited from his 1973 work, clearly reveal Oxnard's acceptance of the reality of human evolution, but Morris and Parker are not interested in Oxnard's evolutionary perspective; they emphasize instead his rejection of the australopithecines from the mainstream of modern human ancestry. They write about Oxnard's findings:
Viewed one way, for example, the pelvic bones of australopithecines seem to be intermediate between man and ape. But merely viewing the bones from a different angle makes the specimen seem as far distant from man as the apes are. "Yet another view," says Oxnard, "might suggest that the fossil arose from the African apes via modern humans!"—in other words, that humans were the missing link between the australopithecines and the apes!
Not only do these authors erroneously reference the word fossil to the phrase "the pelvic bones of australopithecines" when Oxnard's own reference is to the single Olduvai toe bone, but they omit a crucial part of Oxnard's original statement, which read: "Yet another view if assessed naively might suggest that the fossil arose from the African apes via modern humans!" (1979:268; emphasis added). The words if assessed naively were not quoted by Morris and Parker, and this omission leaves the unwary reader with the idea that Oxnard actually thinks such a view is tenable when he clearly does not.
Furthermore, before too much is made of the fact that Oxnard also found that the australopithecine fossils he studied occasionally show more similarities to the orangutan than to other pongid or hominid forms, be assured that he does not conclude that these fossils represent orangutan ancestors! To quote: "This does not mean, of course, that the fossils are related in any genetic way to the orangutan" (1979:273-274). Oxnard's basic position is that the australopithecines were in certain ways unique in their locomotor functions. He thinks that they were bipedal (or, at least, partly so) in a distinctly nonpongid way (1973:165).
What are we to make of Oxnard's 1973 studies? His conclusion that the australopithecines were different from modern humans does not contradict the view held by paleoanthropologists. After all, given an evolutionary perspective, it is to be expected that some of the earliest representatives of the Hominidae were different from the only surviving form today. Keep in mind that he certainly does not conclude that the australopithecines were pongids; rather, he thinks that they were a parallel line of hominid evolution with an earlier common ancestor. It is also important to realize that Oxnard's work has not gone uncritiqued. In the first place, he used only a handful of the fossil materials available for his study. He did not (and to my knowledge still has not) studied any of the specimens from Lake Turkana, Hadar, or Laetoli from which we now have several postcranial specimens that should be considered. One reviewer of his 1973 book noted, among other things, the small sample size Oxnard employed, the "unusual way" that some pelvic measurements were taken that appeared to bias the results, the incompleteness of the Sterkfontein scapula used, and the fact that Oxnard does not mention that the Olduvai talus he did use comes from a virtually complete fossil foot: "This is unfortunate because many claim that this foot is the best evidence there is proving the human affinities of the australopithecines" (McHenry, 1975:988). It should be stressed that Oxnard disagreed with a particular interpretation of australopithecines—not with basic evolutionary views of australopiths (Godfrey in Cole, 1981).
There have also been numerous other studies whose conclusions are at variance with those of Oxnard. One of the principal investigators of australopithecine locomotor patterns is C. Owen Lovejoy. His conclusions about the nature of their bipedalism are especially interesting to contrast to Oxnard's. For example: "It is my opinion that not only are these capabilities [of bipedal walking] clearly in evidence, but that there are, in fact, significant indications that this extinct biped might have been superior to modern man" (1974:151). Lovejoy thinks that the australopithecines were indeed different from modern humans, just as Oxnard concluded, but in an unexpected fashion. On the other hand, Lovejoy writes:
More often than not, the form of the pelvis in Australopithecus has been considered unique—clearly differentiated from that of H. sapiens. This is not necessarily the case, as pelvic form in modern man is highly variable, especially with regard to those features which appear to separate H. sapiens and Australopithecus.
As in Oxnard's case, Lovejoy's conclusions were based upon a sample that did not include specimens from Lake Turkana, Hadar, or Laetoli. But subsequent analysis of several postcranial specimens from Hadar have only reinforced Lovejoy's opinion about the efficiency of the australopithecine pattern of erect bipedalism (Johanson and Edey, 1981:329). Other investigators in this area do not necessarily agree with Lovejoy about the superior efficiency of australopithecine bipedalism, but there is essentially universal agreement that these hominids were clearly erect bipeds (see, for example, the 1979 review article by McHenry and Termerin on the fossil evidence for hominid bipedalism and Gomberg et al., 1984, for divergent views).
There is no doubt about how australopithecines are perceived by paleoanthropologists and evolutionary biologists today. Recognized as early, if not the earliest, hominids, they exhibit some novel adaptations that subsequently led to the evolutionary appearance of the genus Homo and eventually our own species Homo sapiens. Given this view, it might be natural to regard these creatures as the popular "missing link" in the human evolutionary sequence. Such a conclusion, however, is not really consistent with our modern conception of the nature of organic evolution. The notion of a "missing link" frequently connotes the erroneous idea that earlier forms existed almost solely to evolve into some later form. This idea, in turn, is related to the idea of orthogenesis or the notion that evolutionary developments are inevitable and the result of some preestablished goal or aim. Modern evolutionary biological thinking does not accept such an idea as valid.
With specific reference to the australopithecines, Jolly and Plog reflect our current efforts to better understand these creatures:
The features that Australopithecus shares with Homo sapiens are important in that they show us that the genus is hominid, a close relative of Homo sapiens. But they are important for another reason as well. They are part of the total adaptive pattern of Australopithecus—the features that these early hominids developed as they became distinct from their apelike ancestors.
How creationists will continue to deny and reject the taxonomic and evolutionary status of these forms remains to be seen, but surely they will continue to do so. There will be misunderstandings and distortions of both the fossil evidence and the opinions of evolutionary scholars. If the pattern of recent years is any indication of the future, new discoveries will undoubtedly answer some of our current questions, clarify our present understanding, and provide us with new puzzles about the australopithecines.
One question that will surely continue unanswered for quite some time, however, is the one posed by Davis A. Young: "Could Adam have been a creature like Australopithecus?" (1977:153). Now, that is some question!