Search

The human foot serves a dual role during locomotion. It functions at times as a mobile structure and at times as a rigid lever. The human foot shows the hallmarks of an arboreal heritage wherein the foot was primarily a grasping organ. Over the course of the human career the human foot has evolved an elaborate plantar aponeurosis, strong plantar ligaments, longitudinal arches, an enlarged musculus flexor accessorius, an adducted (non-opposable) hallux, a remodeled calcaneocuboid joint, a long tarsus, and shortened toes (II to V). Comparisons of the chimpanzee and human foot allow us to reconstruct the pathway of foot evolution. Fossil foot bones of Homo habilis, dated at 1.76 million years, are remarkably like those of modern humans. Foot bones from Hadar, dated at around 3.5 million years, are remarkably chimpanzee-like, with only incipient human traits. The surprising chimpanzee-like qualities of the Hadar fossils strongly support the use of living apes as models of ancestral pongid-hominid morphotypes.

It was at Trinil, a small village in Central Java, that Eug?ne Dubois found at the end of last century the skullcap and thighbone of an early hominid, namely Pithecanthropus erectus. Today we know that this "ape-man" was much more advanced than Dubois ever supposed. Pithecanthropus is now included in the genus Homo. To be more precise, Pithecanthropus belongs to the species Homo erectus; and th? specimen from Trinil (the first Homo erectus to be found anywhere in the world) forms within it the subspecies Homo erectus erectus. This hominid of Trinil no longer stands in isolation. Also at other places in Java fossil hominid remains have been found, which either belong to this subspecies Homo erectus erectus, or are included in other subspecies (e.g. in Homo erectus soloensis). The most prolific site of fossil hominid remains at the moment is Sangiran, situated some ten kilometres to the north of Surakarta, in Central Java. Homo erectus evolved from Homo habilis on the grassy plains of Upper Pliocene and Basal Pleistocene East Africa some 2 million years ago, and from there he began his wanderings across the Old World. Java was in fact thus the end of a long trek for Homo erectus. But he obviously felt very much at home on Java. There he found a comfortable niche, in which he was able to survive for several hundred thousand years without undergoing many changes. The finds of hominid remains in Java have increased in recent years. This is due to the activities of the Indonesian archaeological service (Pusat Penelitian Arkeologi Nasional), as a result of which research on early man on Java is now proceeding in a coordinated and systematic

Estimation of cranial capacity for Olduvai Hominid (OH) 7 is de- termined from external parietal dimensions using multiple regressions calculated from an australopithecine grade sample. Capacity estimates for OH 7 (580-600 cc) are much lower than usually claimed. While differences in reconstruction may account for the varying estimates, a regression based only on undistorted and un- reconstructed values, as well as a direct comparison of dimensions with other Homo habilis specimens, supports the smaller capacity determination. It would be an understatement to say that times have changed since the discovery and initial interpretation (Leakey, 1961) of the ju- venile hominid specimen from Olduvai gorge, OH 7. Still, some issues concerning the com- parative morphology of the specimen have yet to be settled. Of these, the question of the cra- nial capacity of the vault represented by the two partial parietals has probably received the greatest attention. Holloway's most recent discussion of the OH 7 reconstruction (1980) is an important contribution as well as a useful clarification of some longstanding issues. He has helped clar- ify the question of whether there was substan- tial twisting in the reconstructed fit between the reconstructed parietals. However, other is- sues remain. It is clear, as Holloway states, that the condition of the parietals, the amount of bone preserved, and the accuracy of the re- construction renders them anything but use- less as a basis for volume estimations. Indeed, I know of no worker who has claimed that they were unsuitable for this purpose. How- ever, suitability is one thing, and the appropri- ateness of the estimation is quite another. It is in this area that much of the controversy has been focused. The fact is that the parietals were crushed flat and have been reconstructed, and that be- fore Holloway's most recent paper the volumet- ric estimates based on this reconstruction were determined from a biparietal partial en- docast procedure that has never been adequate- ly tested for accuracy (for details of the recon- struction and the biparietal partial endocast method, see Tobias, 1971). Holloway's most re- cent approach, using multiple regression tech- niques based on measurements taken from other endocasts appears to be more straight- forward. Yet, his results still depend on the accuracy of the reconstruction, as well as on the sample used to generate the regression. With all due respect for Holloway's experience

The proposal of the new australopithecine species Australopithecus afarensis has led to a multiplicity of hypotheses concerning the evolutionary relationships between the known Pliocene and Pleistocene hominid species. We use phylogenetic analysis to gain a new perspective on the subject. Using 69 traits, we construct a series of 12 complexes, each with a defining polarized morphocline. Four mutually exclusive cladograms are derived from these complexes, the most parsimonious of which implies that Homo habilis and A. robustus/boisei are more closely related to each other than either is to A. africanus and that these three species form a distinct evolutionary group relative to the more primitive A. afarensis. We advocate a phylogeny wherein A. afarensis is ancestral to A. africanus, which is in turn ancestral to A. robustus/boisei and H. habilis. We believe that the evolutionary transition from Australopithecus to Homo involved reduction in the size of the chewing teeth and associated traits leading to a u...

A selection of mandibles from recent higher primates, fossil hominids, and hominoids has been studied from photographs of skulls, reproductions, and material published by others, all viewed in the sagittal plane. Tracings of each mandible were constructed so that the dentitions were all scaled to the same length (d) and superimposed. The (scaled) positions of the articular surfaces of the condyles (J = joint point) were compared. The height of each J point above the scaled dentition (h = effective condyle height) and its distance behind the dentition (r = effective ramus width) were compared. With very few exceptions d greater than r greater than d/2. There was a poor correlation between r and the amount of prognathism. The position of the J point with respect to the occlusal plane was different for different groups within the material analysed and could prove to be a useful tool to help improve the reconstruction of fragmented fossil material. Some examples are given. A. afarensis and Homo habilis shared a low and anterior J point (r approximately d/2). The later australopithecines evolved a high and anterior J point, whereas that of Homo erectus was raised and displaced posteriorly (r approximately 3d/4). The value of r was increased to d in the Neanderthals, and recent man has moved the J point forward again. The effect of the position of the J point, the slope of the preglenoid plane, and the curve of Spee on the relationship between upper and lower postcanines when the jaw is opened and then closed to process food have been analysed. The results show that the position of the J point affects the way in which the mandible moves, and this may be related to changes in diet during evolution.

What can palaeontological science contribute to defining circumstances and conditions of the origin of speech abilities? Two ways are successively tried: anatomical and behavioural. o (1) The identification among fossil hominids of some anatomical features (both skeletal and neurological) provides negative evidence in so far as they manifest a potential openness to development of language among Australopithecines and contemporary Homo habilis , although no direct demonstration of its actual existence can be proposed. (2) The interpretation of hominid cooperative hunting behaviour as well as its tcol-making instrumentation and other requirements suggest that some primitive concrete symbolization was available beyond a close call-system, since the time of the first flaking industries, of the late Pliocene.

A bioclimatic model is evaluated as an explanation of variation in cranial capacity among 122 ethnic groups. Distribution of absolute and relative endocranial volume is mapped. Significant correlations occur with all nine climatic variables examined. Major foci of adaptation occur with solar radiation, vapor pressure, and winter temperature. Global mean trait increase is 2.5 cm per degree of equatorial distance. The interactive geometry between cranial size and shape is described, with encephalization and brachycephalization considered as functionally connected trends. Breadth is the most important structural component determining capacity. Relations between body size and brain size indicate that human populations under severe cold stress obtain large volumes more from rounder cranial shape than from differentiation by total body size. A computerized mapping program is developed and applied to anthropometric, climatic, and HRAF files. Its potential to produce clinal depictions through the Pleistocene ("ti...

The australopithecine anterior pillars defined by Rak (The Australopithecine Face, New York: Academic Press, 1983) were re-examined in the fossil hominids of southern Africa. The structure and extent of this buttressing pillar was found to be variable among Australopithecus africanus and A. robustus specimens. A reduced anterior pillar was observed in Homo habilis, and a morphological equivalent can be discerned in modern specimens of H. sapiens. The anterior pillars and associated features can be viewed as a response to the occlusal forces of the entire anterolateral dentition, with a special affinity to the canine but limited functional relationship to the "molarized premolars. Furthermore, a functional assessment of the hominid masticatory biomechanics implies that the adaptations ofA. africanus are well within our expectations of a viable ancestor to the genus Homo and are not irrevocably derived toward a "robust" type of adaptation. Morphological features of the craniofacial systems provide us with vital and distinctive information on which to base hypotheses concerning human evolution. In a thorough description of australopithecine facial topog- raphy, Rak (1983) was able to identify some key biomechanical features of the australo- pithecine masticatory morphology. These features have been used in interpretations of masticatory function and further applied to phylogenetic systematics (Rak, 1983, 1985a-c; White et al., 1981).

To estimate stature in fossil hominids, researchers generally use the Trotter & Gleser (1952, 1958) equations. These equations are based on a sample whose individuals are larger than the fossil sample to which they are customarily applied. This results in significant overestimates of early hominid statures. We offer here revised stature estimates for 15 reasonably well-preserved African Plio-Pleistocene hominid femora and tibiae (including AL 288-1 and WT 15000) based on least squares and major axis regression equations we developed for contemporary South African black tribal populations. By using this smaller and more homogeneous extant African sample, we predict that most of these hominids were smaller than McHenry's (and those subsequent) estimates have suggested. In the case of AL 288-1, our Model II estimate matches almost exactly Schmid's (1983; 1986; Geissmann 1986a) anatomical reconstruction, while it differs significantly from the estimates derived from analyses of Olivier's recommended pygmy population. Although there is some disproportionality in the AL 288-1 lower limb, evidence is provided here to indicate that its effect on our stature estimates is probably small. This permits greater confidence to be placed in our estimates of her stature. In the final analysis, we find that except for Homo erectus the various groups of early hominids have overlapping ranges and differ little from one another in stature.

Microscopic analysis reveals specific patterns of wear facets on dental crowns in early hominids from Laetoli, Hadar and Olduvai. The analysis of dental microwear patterns provides an important adjunct for determining Australopithecus afarensis and Homo habilis feeding behaviors and therefore provides an additional source of information for understanding human evolution.

The cranial capacity of Olduvai Hominid 7 is estimated to be 690 cc, with a standard uncertainty range of 538 to 868 cc. The estimate is derived from a systematic consideration of the relationships between Bregma-Asterion chords and cranial capacities obtained from a large sample of Homo sapiens and Pan troglodytes and from available fossil hominids. The estimation technique is applicable to other characters and specimens.

The faunas of three fossil sites in Africa that contain time successive groups of fossil Hominoidea have been analyzed to determine their paleoenvironments. The basis for the analysis is an assessment of the ecological diversity of the fauna, which is expressed in terms of four categories: taxonomic composition, body size, feeding habits and locomotor zonal adaptation. This method has shown that the community structures of the three fossil faunas are significantly different, and comparisons with the community structure of modern habitats suggest that the environment of the early Miocene fauna of Songhor, and the primitive apes associated with it, was probably a type of lowland forest; the habitat ofRamapithecusand the Fort Ternan middle Miocene fauna compares best with modern woodland-bushland habitats; and the habitat ofHomo habilisat Olduvai appears to have been intermediate between grassland and woodland-bushland. If man evolved from one of the early forest living apes, as seems likely on present evidence, an adaptive shift from forest to non-forest habitats must have occurred at some stage in his evolution. The evidence from Fort Ternan shows that in AfricaRamapithecusmade this adaptive shift, and it is also now becoming clear that several genera of Eurasian apes, includingRamapithecus, made a similar environmental change at the same time.

The question of whether there is a fundamental discontinuity between humans and other primates is discussed in relation to the predominantly human pattern of right-handedness and the left-cerebral representation of language. Both phenomena may go back at least to Homo habilis, 2-3 million years ago. However, a distinctively human mode of cognitive representation may not have emerged until later, beginning with H. erectus and the Acheulean tool culture about 1.5 million years ago and culminating with H. sapiens sapiens and rapid, flexible speech in the last 200,000 years. It is suggested that this mode is characterized by generativity, with multipart representations formed from elementary canonical parts (e.g., phonemes in speech, geons in visual perception). Generativity may be uniquely human and associated with the left-cerebral hemisphere. An alternative, analogue mode of representation, shared with other species, is associated with the right hemisphere in humans.

Craniofacial traits of two crania from Koobi Fora, Kenya, KNM-ER 1470 and KNM-ER 1813, are compared to determine the probability that they are from the same species, Homo habilis . It is argued that unless Homo habilis was significantly more sexually dimorphic than Gorilla gorilla , it is improbable that the two fossils can both be classified as Homo habilis . The creation of at least one new species is required to account for the morphological and metrical variation of Late Pliocene-Early Pleistocene Homo fossils in eastern Africa.

New postcranial fossils of Paranthropus robustus and Homo cf. erectus were recovered from Swartkrans from 1979 through 1986. These fossils are from Members 1, 2, and 3. The new fossils are described here along with their morphological affinities. Fossils that are assigned to Paranthropus indicate that the South African "robust" australopithecines engaged in tool behavior and were essentially terrestrial bipeds at around 1.8 Myr BP. The manual dexterity and bipedal locomotion of Paranthropus may have equaled that of Homo habilis in East Africa at approximately the same time.

Since 1936 the site of Sterkfontein has been best known for its fossils attributed to Australopithecus africanus. From 1966 a continuous excavation programme at Sterkfontein has uncovered not only numerous fossils of that species but also a small number of Homo habilis remains associated with stone tools, including handaxes and cleavers of the Early Acheulean. Vertical plots have shown a clear separation between Australopithecus fossils in a talus cone to the east and Homo habilis fossils with stone tools to the west. The Australopithecus bones which were probably dropped through a slot in the original cavern roof by big cats are here argued to represent two species which have erroneously been grouped as one. The first with smaller teeth is Australopithecus africanus and was the probable direct ancestor to Homo. The second species has large teeth and a cranial morphology trending toward Paranthropus.

Understanding of the early stages of hominid evolution prior to 1925 was based primarily on comparative morphological evidence derived from extant primates. With the publication of Australopithecus by Dart in 1925 and subsequent research in South Africa, new possibilities for empirical assessment of early hominid evolutionary history were opened. It was Gregory's work, with Hellman, reported at the first meeting of the AAPA in 1930, that convinced many workers of the hominid status of Australopithecus. The debunking of Eoanthropus as a Pliocene hominid, far from having a totally negative effect, showed that cranial expansion had occurred after bipedalism in hominid evolution, demonstrated that chemical dating had come of age, and in a broader sense, had underlined that phylogenetic hypotheses are falsifiable by recourse to the evidence. The input of biological sciences into early hominid studies, as exemplified by Washburn's “new physical anthropology,” reduced taxonomic diversity and focused attention on paleoecology and behavior. The development of the multidisciplinary approach to field research, pioneered by L. Leakey and brought to fruition by Howell, was of fundamental importance in accurately dating and understanding the context of early hominids. Archaeology, primatology, comparative and functional morphology, and morphometrics have contributed substantially in recent years to a fuller understanding of early hominid evolution. American granting agencies have heavily supported early hominid research but patterns of funding have not kept pace with the change from research based largely on individualistic enterprise to multidisciplinary research projects. Future early hominid research, if funding is available, will likely be directed toward investigating temporal and geographic gaps now known in the fossil record and in more rigorous and multidisciplinary investigations of early hominid behavior.

Using the PAUP (phylogenetic analysis using parsimony) program, nine different hominid groups allocated to the genus Homo have been included in a numerical cladistic analysis. Eleven (essentially continuous) characters, mainly cranial, have been used for the analysis, and the most parsimonious trees generated by PAUP have been compared with a “conventional” tree provided by the author. PAUP's three best trees all assign the early archaic H. sapiens group to a clade containing early African H. erectus and Asian H. erectus, rather than to the clade containing Neanderthals, African late archaic H. sapiens, Skhūl-Qafzeh and modern H. sapiens. Relationships within the latter clade could not be resolved elearly by PAUP, although the Skhūl-Qafzeh and modern H. sapiens groups were consistently linked through synapomorphies. As long as ordered characters were used, the two subsets of H. habilis were treated as plesiomorphous, while modern H. sapiens was highly derived, suggesting that characters in common were homoplasies.

A new complete hallucal metatarsal (SKX 5017) was recovered from the "lower bank" of Member 1 at Swartkrans (ca. 1.8 m.y. BP). The new metatarsal is attributed to Paranthropus robustus, the predominant hominid found in Member 1 (greater than 95% of hominid individuals). SKX 5017 is similar to Olduvai Hominid 8-H from bed I, Olduvai (ca. 1.76 m.y. BP), and both resemble humans most closely among extant hominoids. The base, shaft, and head of SKX 5017 suggest human-like foot posture and a human-like range of extension (= dorsiflexion) at the hallucal metatarsophalangeal joint, while at the same time the distal articular surface indicates that a human-like toe-off mechanism was absent in Paranthropus. The fossil evidence suggests that Homo habilis and Paranthropus may have attained a similar grade of bipedality at roughly 1.8 m.y. BP.

Large carnivores structure the character of scavenging opportunities in any environment. In Pliocene and early Pleistocene Africa there were three large sabertooth cats sympatric with the ancestors of the modern felid community, and scavenging opportunities were presumably different from those in modern Africa. An understanding of a possible scavenging niche for early hominids must articulate knowledge gained from actualistic research with detailed reconstructions of extinct carnivore paleoecology. Contrasting skeletal and dental anatomy suggest that sabertooths and modern felids were ecologically distinct. Evidence from functional morphology and fossil associations elucidates the distinctions. Sabertooth incisor and carnassial morphology indicates extreme flesh specialisation and lack of bone-crushing ability. Sabertooth cranial morphology and fossil associations suggest a specialisation upon very large prey. The post-cranial morphology of sabertooths indicates a dense woodland and forest habitat preference. This implies that two distinct large carnivore communities existed in the Pliocene and early Pleistocene: a mixed and open habitat community composed of the ancestors of the extant carnivore community plus Chasmaporthetes, and a closed habitat community dominated by the sabertooths. Scavenging opportunities in the closed habitat community would have been much better than in more open habitats. Homo habilis with its inferred arboreal abilities could have passively scavenged very effectively in dense woodlands and forests. Paleoenvironmental and paleontological data indicate that these closed habitats shrunk after 1·7 million years ago and the sabertooths probably went extinct in sub-Saharan Africa. Homo habilis perhaps increasingly utilised more open habitats and would have been forced to confront large predators to gain adequate scavenging returns. Archaeological data of stone tool raw materials and site placement suggests that early hominids switched from an emphasis on dense woodland habitats to increased usage of more open habitats after 1·6 million years ago. Confrontational scavenging along with increased predation pressure may have contributed to the morphological changes associated with the shift to Homo erectus.

Analysis of prehistoric stone artifacts from Lower Pleistocene sites at Koobi Fora, Kenya, and Middle Pleistocene horizons at Ambrona, Spain reveals a preferential, clockwise rotation of stone cores during flaking. Experimental studies of early stone artifact manufacture show that this non-random pattern is consistent with that produced by right-handed toolmakers. This suggests that there was a genetic basis for right-handedness by 1·4 to 1·9 million years ago, and that there may have already been a profound lateralization in the hominid brain with the two hemispheres becoming more specialized for different functions.

New studies have been made on endocranial casts of Olduvai specimens of Homo habilis. The results have been compared with those on other East African H. habilis and other hominoids. The mean absolute endocranial capacity of H. habilis is appreciably larger than the mean for australopithecine species: on the new estimates, the H. habilis mean is 45·1% greater than the A. africanus mean and 24·8% greater than that of A. boisei. New data for relative brain size, expressed by Jerison's Nc and EQ and Hemmer's CC, strongly confirm that it was with H. habilis that there appeared the remarkable autapomorphy of Homo, disproportionate expansion of the brain. Encephalometric studies reveal marked transverse expansion of the cerebrum, especially the frontal and parieto-occipital parts, in H. habilis and increased bulk of the frontal and parietal lobes, a derived feature of Homo. There is moderate cerebral heightening, but little or no cerebral lengthening. The sulcal and gyral pattern of the lateral part of the frontal lobe of H. habilis differs from those of Australopithecus and resembles the derived pattern of Homo. The inferior parietal lobule is prominently developed—an autapomorphy of Homo. The two major cerebral areas governing spoken language in modern man are well represented in the endocasts of H. habilis, a functionally important autapomorphy of Homo. The pattern of middle meningeal vessels is more complex with more anastomoses than in australopithecines: H. habilis shares this derived feature with later forms of Homo. In all these features, the brain of H. habilis had made major advances, beyond the more ape-like australopithecine brain. With H. habilis, cerebral evolution had progressed beyond the stage of “animal hominids” (Australopithecus spp.) to that of “human hominids” (Homo spp.). In functional capacity, in particular, its possession of a structural marker of the neurological basis of spoken language, H. habilis had attained a new evolutionary level of organization.

o (1) At Bossou in Guinea, and at Beatty's site in Liberia, chimpanzees use stone hammers and anvils to crack cultivated oil palm nuts in order to eat the kernel. They do so in the human manner and do not crack wild fruit. Elsewhere in the geographical range of the species, in most areas where oil palms commonly occur, chimpanzees swallow the whole fruit, digest the outer layer, and defaecate the nuts undamaged. Evidence from Bossou suggests that the habit of cracking oil palm nuts by means of stone tools has been copied by the chimpanzee community from the local human population as a result of observational learning under pressure of habitat deterioration. This community and Beatty's may represent the first identifiable cases of direct cultural transmission of technology from man to animal in the wild. (ii) At several sites in a region that ranges from the SE tip of Sierra Leone to the SW part of the Ivory Coast, chimpanzees use much heavier hammer stones in more varied ways than at Bossou to crack the very hard nuts of certain wild fruit species, while they do swallow oil palm fruit but do not crack these nuts. At two sites (at least) they also use wooden clubs as hammers, and roots and branches of trees as anvils. The manipulation techniques require a degree of arboreal competence, manual dexterity and integration of skills that far exceeds that currently observed among chimpanzees elsewhere in Africa. A possible explanation might be that this region is covered by the most humid type of evergreen lowland rain forest, and has been the most important lowland rain forest refuge of West Africa during dry epochs in the Pleistocene. Consequently the apes in this area may have been genetically selected for, and culturally adapted to, a highly specialized way of life in such habitats for hundreds of thousands, or perhaps millions, of years. (iii) With chimpanzees, the direction of the blow of the hammer on the nut follows the perpendicular to a flat surface of the hammer through its gravity centre. No similar use of stone tools has been inferred from the earliest hominid artefacts. On the contrary, nearly all early hominid stone tools were used as cutting, cleaving and chopping devices over the entire lengths of their edges. A cause of this difference might be that chimpanzees (in the trees) often have only one hand free both for positioning the nut and for subsequently wielding the hammer, while hominids (on the ground) could simultaneously use one hand to hold the object and the other hand to manipulate the tool. Moreover, “Nutcracker Man” may have cracked edible nuts with his teeth while Homo habilis may have developed the use of stone tools primarily for butchering prey or carrion. In conclusion, the use of stone tools by chimpanzees and earliest hominids shows no indications of homology, functional equivalence, similarity of motor patterns or identity of motivation.

A fragmentary hominid cranium with teeth, specimen L.894-1, dating from 1.84 m.y. BP in the Shungura Formation at Omo, is described. From its dental and cranial morphology and because of similarities to Olduvai Hominids 24 and 13 and Sangiran 4, among others, it is concluded that the specimen represents a member of an early species of the genus Homo (Homo habilis or Homo modjokertensis). The specimen shows approximal grooving on the premolars, pre-mortem chipping of the molar enamel, foramina ovale and spinosum divided by the sphenosquamosal suture, limited pneumatization of the mastoid region, and a possible interparietal bone. Sedimentological, ostracod, pollen, macrofloral, and taphonomic data indicate that the paleo-environmental context was a savanna/grassland or savanna woodland on the margin of a saline lake.

The nature of stone artifact concentrations at early Plio-Pleistocene sites in East Africa is evaluated with regard to hominid transport behaviors responsible for their formation. These archaeological occurrences indicate ranging behaviors involving deliberate and repeated transport of flaked stone artifacts. The stone transported to archaeological sites within the time range of Homo habilis indicates planned transport of tools or material for tool manufacture to an extent far beyond transport behaviors reported among living apes, even stone hammer-using chimpanzees. Analysis of technological evidence in a lithic assemblage at a Plio-Pleistocene site at Koobi Fora (c. 1·5 ya) indicates on-site manufacturing activities and transport of flaked stone both to and from the site locale. Possible explanations for transport of stone artifacts are discussed in view of hominid strategies of environmental exploitation and resource utilization. A model is proposed for planned, habitual transport of artifacts by hominids positively correlated with distance of planned foraging range. In this model, larger-scale sites tended to develop at locales favorably located near abundant resources, where stone imports were high but export was relaxed due to the proximity of resources to be processed.

The discovery of Australopithecus afarensis has led to new interpretations of hominid phylogeny, some of which reject A. africanus as an ancestor of Homo. Analysis of buccolingual tooth crown dimensions in australopithecines and Homo species by Johanson and White (Science 202:321-330, 1979) revealed that the South African gracile australopithecines are intermediate in size between Laetoli/hadar hominids and South African robust hominids. Homo, on the other hand, displays dimensions similar to those of A. afarensis and smaller than those of other australopithecines. These authors conclude, therefore, that A. africanus is derived in the direction of A. robustus and is not an ancestor of the Homo clade. However, there is a considerable time gap (ca. 800,000 years) between the Laetoli/Hadar specimens and the earliest Homo specimens; "gracile" hominids from Omo fit into this chronological gap and are from the same geographic area. Because the early specimens at Omo have been designated A. afarensis and the later specimens classified as Homo habilis, Omo offers a unique opportunity to test hypotheses concerning hominid evolution, especially regarding the phylogenetic status of A. africanus. Comparisons of mean cheek teeth breadths disclosed the significant (P less than or equal to 0.05) differences between the Omo sample and the Laetoli/Hadar fossils (P4, M2, and M3), the Homo fossils (P3, P4, M1, M2, and M1), and A. africanus (M3). Of the several possible interpretations of these data, it appears that the high degree of similarity between the Omo sample and the South African gracile australopithecine material warrants considering the two as geographical variants of A. africanus. The geographic, chronologic, and metric attributes of the Omo sample argue for its lineal affinity with A. afarensis and Homo. In conclusion, a consideration of hominid postcanine dental metrics provides no basis for removing A. africanus from the ancestry of the Homo lineage.

As early as 1963, Richard Evans Schultes wrote (1): "It is of interest that the New World is very much richer in narcotic plants than the Old and that the New World boasts at least 40 species of hallucinogenic or phantastica narcotics (2) as opposed to half a dozen species native to the Old World." The reason for this marked discrepancy is by no means immediately apparent. In point of fact, one might reasonably suppose that the reverse would be the case. That is, the Old World has a far greater land mass than the New and certainly as varied climates, and hence the apparent possibility of a greater number and variety of plants. Furthermore, men and proto-men who might have discovered the properties of those plants that are narcotic have existed for an incomparably longer period (from the Australopithecines and Homo habilis onward) in the Old World than in the New (only from the Late Paleolithic and Mesolithic onward). Thus, on geographicecological and botanical and also on anthropological grounds, the Old World prima facie should hold more psychotropic plant species than the New-which is quite contrary to the apparent facts. On returning to the problem in 1966, Schultes (3) cited the statistics again but cautioned: ". . . the foregoing statistics relate merely to those plants the narcotic properties of which man has discovered in his trial and error experimentation during human history. Is there any reason to presume that man in a primitive state of culture possesses any peculiar intuition enabling him to uncover more efficiently than his more civilized counterpart those plants that Nature has endowed with physiologically active principles?" There is, I think, an answer in this. But

Volumetric data are presented for 16 of the early hominids from both South and East Africa. Although the sample sizes are small, the statistical data support the conclusion that at least three taxa are represented; Australopithecus africanus, A. robustus , and Homo habilis . These data, plus certain morphological attributes, indicate that the brains of early hominids were reorganized to a human pattern, regardless of their small endocranial capacities. Some speculative suggestions are made regarding the possible relationship between brain and body weights, as well as Stephan's (1972) “progression indices”. If the speculations are correct, they provide additional support for the idea that brain reorganization occurred early in human evolution, and that concepts which regard the brain as having a more terminal role in human mosaic evolution are incorrect, as all of the fossil encephalization or “progression indices” are in the range of modern Homo sapiens .

Changes in the hallucial tarsometatarsal joint, which forms the fulcrum for the grasping hallux, have played a significant role in primate evolution. Comparative studies suggest that one of the morphological novelties heralding the attainment of a monkey grade of structure was the incorporation of the prehallux within this joint. Such a joint is found in the extant Ceboidea and, paradoxically, the Hylobatidae. Hallux and prehallux then form a composite distal articular surface; the proximal surface on the medial cuneiform is completed inferomedially by a convex facet for the prehallux. Divergence of the hallux into the attitude of opposition is accompanied by conjunct rotation, screwing these joint components into a stable, close-packed position. Suppression of the prehallux is accompanied by clear osteological indicators — the absence of prehallux facets on the first metatarsal and medial cuneiform. This modification of the joint is a feature of cercopithecoid evolution, and has also occurred in the hominoid line, after divergence of the ancestral gibbons and apparently after the Dryopithecus (Proconsul) stage. The cladistic relationships indicated by these morphological changes are in striking accord with recent results on primate evolution at the molecular level.