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The secondary literature on Trần Đức Thảo has practically never taken into account his linguistic-philosophical writings of the 1980s. In the following paper, we will give the reader an overall overview of this work, from the publication of Investigations into the Origins of Language and Consciousness through Trần Đức Thảo’s return to Paris in 1991. In the 1980s, two solutions to the puzzle of the origin of language and consciousness can be observed in his published and unpublished texts. Both radically differ from what Thảo suggested in the 1960s and 1970s. In the following paper, we will also highlight the political commitment that provides context for Thảo’s research.

South Africa and East Africa each have a rich palaeoanthropological heritage, but the taxonomy of fossil hominins from these regions is controversial. In this study, two morphometric methods related to the quantification of variability in morphology have been applied to pairwise comparisons of linear measurements of hominoid crania and mandibles. The log-transformed standard error of the m-coefficient (‘log sem’) is calculated from linear regressions. Like Procrustes Distances (PD), log sem statistics can serve to quantify variation in the shape of a cranium or mandible in the context of a constellation of landmarks. In this study, PD and log sem statistics are integrated and standardised using Z-scores, and applied probabilistically to Plio-Pleistocene hominins. As a test case, OH 7 and OH 24 as reference specimens of Homo habilis are compared to fossils representing other taxa. There is a wide spectrum of variation in Z-scores for specimens attributed to early Homo dated within the period between circa 1.8 Ma and 2 Ma. In terms of morphometric variation predating 1.8 Ma, Z-scores (Z

The earliest South African hominids (humans and their ancestral kin) belong to the genera Australopithecus, Paranthropus, and Homo, with the oldest being a ca. 3.67 million-year-old nearly complete skeleton of Australopithecus (StW 573) from Sterkfontein Caves. This skeleton has provided, for the first time in almost a century of research, the full anatomy of an Australopithecus individual with indisputably associated skull and postcranial bones that give complete limb lengths. The three genera are also found in East Africa, but scholars have disagreed on the taxonomic assignment for some fossils owing to historical preconceptions. Here we focus on the South African representatives to help clarify these debates. The uncovering of the StW 573 skeleton in situ revealed significant clues concerning events that had affected it over time and demonstrated that the associated stalagmite flowstones cannot provide direct dating of the fossil, as they are infillings of voids caused by postdepositional collapse. [ABSTRACT FROM AUTHOR]

The human trophic level (HTL) during the Pleistocene and its degree of variability serve, explicitly or tacitly, as the basis of many explanations for human evolution, behavior, and culture. Previous attempts to reconstruct the HTL have relied heavily on an analogy with recent hunter‐gatherer groups' diets. In addition to technological differences, recent findings of substantial ecological differences between the Pleistocene and the Anthropocene cast doubt regarding that analogy's validity. Surprisingly little systematic evolution‐guided evidence served to reconstruct HTL. Here, we reconstruct the HTL during the Pleistocene by reviewing evidence for the impact of the HTL on the biological, ecological, and behavioral systems derived from various existing studies. We adapt a paleobiological and paleoecological approach, including evidence from human physiology and genetics, archaeology, paleontology, and zoology, and identified 25 sources of evidence in total. The evidence shows that the trophic level of the Homo lineage that most probably led to modern humans evolved from a low base to a high, carnivorous position during the Pleistocene, beginning with Homo habilis and peaking in Homo erectus. A reversal of that trend appears in the Upper Paleolithic, strengthening in the Mesolithic/Epipaleolithic and Neolithic, and culminating with the advent of agriculture. We conclude that it is possible to reach a credible reconstruction of the HTL without relying on a simple analogy with recent hunter‐gatherers' diets. The memory of an adaptation to a trophic level that is embedded in modern humans' biology in the form of genetics, metabolism, and morphology is a fruitful line of investigation of past HTLs, whose potential we have only started to explore. [ABSTRACT FROM AUTHOR]

Objectives: The taxonomic status of isolated hominoid teeth from the Asian Pleistocene has long been controversial due to difficulties distinguishing between pongine and hominin molars given their high degree of morphometrical variation and overlap. Here, we combine nonmetric and geometric morphometric data to document a dental pattern that appears to be taxonomically diagnostic among Pongo. We focus on the protoconule, a cuspule of well‐documented evolutionary history, as well as on shape differences of the mesial fovea of the upper molars. Materials and methods: We examined 469 upper molars of eight hominid genera (Australopithecus, Paranthropus, Homo, Meganthropus, Sivapithecus, Pan, Gorilla, and Pongo), including representatives of Homo erectus and extinct and recent Pongo. Analyses were conducted at the enamel‐dentine junction to overcome the limitations introduced by dental wear. Results: We found that a moderate or large protoconule is present in ~80% of Pleistocene and extant Pongo. Conversely, a moderate to pronounced protoconule in hominins, Meganthropus, and African great apes occurs in low frequencies (~0–20%). Canonical variate analyses for the mesial fovea show that Pleistocene and extant Pongo cluster together and are clearly differentiated from all other groups, except for Sivapithecus. Discussion: This study suggests that the protoconule and the shape of the mesial fovea in upper molars are useful features for the taxonomic identification of isolated hominid teeth. By identifying these new features, our results can contribute to the better understanding of hominoid evolutionary history and biogeography during the Asian Pleistocene. However, we emphasize that the reported features should be used in combination with other diagnostic variables for the most accurate taxonomic assessments. [ABSTRACT FROM AUTHOR]

Relative fibular/tibial strength has been demonstrated to vary with locomotor behavior among anthropoid primates. In this study fibular/tibial strength was determined in KNM-WT 15000, a juvenile Homo erectus individual (1.5 Ma), and in OH 35, a Homo habilis (or possibly Paranthropus boisei) individual (1.8 Ma), and compared to that of adult modern humans (n = 79), chimpanzees (n = 16), gorillas (n = 16) and orangutans (n = 11). Ontogenetic changes in fibular/tibial strength were also analyzed due to KNM-WT 15000's juvenile status. Cross-sectional properties at midshaft were derived from multi-plane radiography and external contours, or CT scanning. Comparisons of log-transformed fibular/tibial polar second moment of area and anteroposterior (A-P) and mediolateral (M-L) second moments of area were carried out between extant species. Fossil deviations from each extant taxon's mean proportion were calculated in standard deviation (SD) units for that taxon. Great apes differ significantly from modern humans, with relatively stronger fibulae, particularly in the M-L plane. KNM-WT 15000 is more than 2 SD from all great apes (≥3 SD in the M-L plane) and within 1 SD of modern humans for almost all variables. This is not a result of its age, as fibular/tibial strength slightly decreases with age (i.e., becomes less like that of great apes) in humans. OH 35 falls within 1 SD of chimpanzees and orangutans for the majority of cross-sectional proportions, but more than 1 SD from humans. KNM-WT 15000 is demonstrated to be fully modern, complimenting other indications of complete terrestrial bipedality and possibly showing adaptations for endurance running. OH 35 has some human-like features; however, the relative strength of the two bones aligns the specimen with great apes, consistent with a significant degree of arboreality, in particular, vertical climbing. [ABSTRACT FROM AUTHOR]

Fossil bird data (community composition and taphonomic profiles) are used here to infer the environmental context of the Oldowan-Acheulean transitional period at Olduvai Gorge, Tanzania. This is the first comprehensive report on the Middle Bed II avifauna and includes fossils excavated by the Olduvai Geochronology and Archaeology Project (OGAP) and recently rediscovered fossils collected by Mary Leakey. Crane, ibis, darter, owl, raptor, crow, and vulture are reported from Bed II for the first time. The presence of these taxa, absent earlier in this Bed, point to a general opening and drying of the landscape with grassland and open woodland expansion. Taxa associated with dense, emergent wetland vegetation, such as dabbling ducks and rails, are uncommon and less diverse than earlier in Bed II. This suggests more mature wetlands with clearer waters. Cormorants continue to be common, but are less diverse. Cormorants and other roosting taxa provide evidence of trees in the area. Compared to lowermost Bed II, the Middle to Upper Bed II landscape is interpreted here as more open and drier (but not necessarily more arid), with matured wetlands, scattered trees, and a greater expansion of grasslands. [ABSTRACT FROM AUTHOR]

Archaeological excavations at EF-HR and HWK EE allow reassessment of Bed II stratigraphy within the Junction Area and eastern Olduvai Gorge. Application of Sequence Stratigraphic methods provides a time-stratigraphic framework enabling correlation of sedimentary units across facies boundaries, applicable even in those areas where conventional timelines, such as tephrostratigraphic markers, are absent, eroded, or reworked. Sequence Stratigraphically, Bed II subdivides into five major Sequences 1 to 5, all floored by major disconformities that incise deeply into the underlying succession, proving that simple "layer cake" stratigraphy is inappropriate. Previous establishment of the Lemuta Member has invalidated the use of Tuff IIA as the boundary between Lower and Middle Bed II, now redefined at the disconformity between Sequences 2 and 3, a lithostratigraphic contact underlying the succession containing the Lower, Middle, and Upper Augitic Sandstones. HWK EE site records Oldowan technology in the Lower Augitic Sandstone at the base of Sequence 3, within Middle Bed II. We suggest placement of recently reported Acheulean levels at FLK W within the Middle Augitic Sandstone, thus emphasizing that handaxes are yet to be found in earlier stratigraphic units of the Olduvai sequence. This would place a boundary between the Oldowan and Acheulean technologies at Olduvai in the Tuff IIB zone or earliest Middle Augitic Sandstone. A major disconformity between Sequences 3 and 4 at and near EF-HR cuts through the level of Tuff IIC, placing the main Acheulean EF-HR assemblage at the base of Sequence 4, within Upper rather than Middle Bed II. Sequence stratigraphic methods also yield a more highly resolved Bed II stratigraphic framework. Backwall and sidewall surveying of archaeological trenches at EF-HR and HWK EE permits definition of “Lake-parasequences” nested within the major Sequences that record downcutting of disconformities associated with lake regression, then sedimentation associated with lake transgression, capped finally by another erosional disconformity or hiatal paraconformity caused by the next lake withdrawal. On a relative time-scale rather than a vertical metre scale, the resulting Wheeler diagram framework provides a basis for recognizing time-equivalent depositional episodes and the position of time gaps at various scales. Relative timing of archaeological assemblage levels can then be differentiated at a millennial scale within this framework. [ABSTRACT FROM AUTHOR]

The regular consumption of large mammal carcasses, as evidenced by butchery marks on fossils recovered from Early Stone Age archaeological sites, roughly coincides with the appearance of Homo habilis . However, the significance of this niche expansion cannot be appreciated without an understanding of hominin feeding behavior and their ecological interactions with mammalian carnivores. The Olduvai Geochronology and Archaeology Project (OGAP) has recovered a large and well-preserved fossil assemblage from the HWK EE site, which was deposited just prior to the first appearance of Acheulean technology at Olduvai Gorge and likely represents one of the last H. habilis sites at Olduvai. This taphonomic analysis of the larger mammal fossil assemblage excavated from HWK EE shows evidence of multiple occupations over a long period of time, suggesting the site offered resources that were attractive to hominins. There was a water source indicated by the presence of fish, crocodiles, and hippos, and there was possible tree cover in an otherwise open habitat. The site preserves several stratigraphic intervals with large fossil and artifact assemblages within two of these intervals. Feeding traces on bone surfaces suggest hominins at the site obtained substantial amounts of flesh and marrow, particularly from smaller size group 1–2 carcasses, and exploited a wide range of taxa, including megafauna. A strong carnivore signal suggests hominins scavenged much of their animal foods during the two main stratigraphic intervals. In the later interval, lower carnivore tooth mark and hammerstone percussion mark frequencies, in addition to high epiphyseal to shaft fragment ratios, suggest hominins and carnivores did not fully exploit bone marrow and grease, which may have been acquired from nutritionally-stressed animals that died during a dry period at Olduvai. The diversity of fauna that preserve evidence of butchery suggests that the HWK EE hominins were opportunistic in their acquisition of carcass foods. [ABSTRACT FROM AUTHOR]

HWK EE is a little-known archaeological site from the top of Lower Bed II and the basal part of Middle Bed II, Olduvai Gorge, Tanzania. The site was originally excavated in the early 1970s by Mary Leakey, but the excavations and resulting lithic and fossil assemblages were never described. Here we report for the first time on the lithic and fossil assemblages that were recovered by Mary Leakey from the site. The lithic assemblage is one of the largest of any Oldowan site and is characterized by a core-and-flake technology with simple flaking techniques and minimal reduction of cores. Retouched flake frequencies and battered tools are higher than those reported for Olduvai Bed I and Lower Bed II assemblages, but flaking schemes are poorly organized. The fossil assemblage is well-preserved, taxonomically-rich, but dominated by bovids, and includes abundant feeding traces of both hominins and carnivores. Hominins are inferred to have broken the majority of limb bones at the site for access to marrow, while both carnivores and hominins likely had access to at least some flesh. HWK EE may represent one of the last Homo habilis sites at Olduvai Gorge, and is important to understanding the behavioral and cultural mechanisms that led to the emergence of the Acheulean and Homo erectus in the region. [ABSTRACT FROM AUTHOR]

Hominins and carnivores have shared similar habitats in Africa, evolving as direct competitors for the same prey and spaces. The overlap of their ecological niches has raised an important debate on the role that carnivores played in archaeological site formation. Different analytical techniques differentiate the action of carnivores and humans and identify the type of carnivore involved of which tooth mark analyses are prominent. However, available taphonomic studies present some limitations given the great overlap among tooth mark sizes from different carnivores, enabling only the distinction of size groups, not specific carnivores. In this work, we use a new technique combining three-dimensional (3D) reconstruction and geometric morphometrics (GMM) of tooth pits on equid and bovid bone created by different carnivores (including crocodiles, hyenas, jaguars, lions and wolves) in controlled settings. The 3D methodology we present isolates and differentiates tooth marks generated by different carnivores. We also test the applicability of the technique to ascribe tooth pits recorded on some hominin specimens from FLK Zinj and FLKNN 3 (Bed I, Olduvai Gorge). The tooth marks on the Olduvai OH8 and OH35 hominin fossils, previously assigned to crocodiles show that while OH8 tooth pit morphology falls in the range created by crocodiles, the pits on OH35 can not be interpreted as crocodile-inflicted marks. [ABSTRACT FROM AUTHOR]

New fossil discoveries and new analyses increasingly blur the lines between Australopithecus and Homo, changing scientific ideas about the transition between the two genera. The concept of the genus itself remains an unsettled issue, though recent fossil discoveries and theoretical advances, alongside developments in phylogenetic reconstruction and hypothesis testing, are helping us approach a resolution. A review of the latest discoveries and research reveals that ( a) despite the recent recovery of key fossil specimens, the antiquity of the genus Homo remains uncertain; ( b) although there exist several australopith candidate ancestors for the genus Homo, there is little consensus about which of these, if any, represents the actual ancestor; and ( c) potential convergent evolution (homoplasy) in adaptively significant features in late australopiths and basal members of the Homo clade, combined with probable reticulate evolution, makes it currently impossible to identify the direct ancestor of Homo erectus. [ABSTRACT FROM AUTHOR]

Although the diminutive Homo floresiensis has been known for a decade, its phylogenetic status remains highly contentious. A broad range of potential explanations for the evolution of this species has been explored. One view is that H. floresiensis is derived from Asian Homo erectus that arrived on Flores and subsequently evolved a smaller body size, perhaps to survive the constrained resources they faced in a new island environment. Fossil remains of H. erectus , well known from Java, have not yet been discovered on Flores. The second hypothesis is that H. floresiensis is directly descended from an early Homo lineage with roots in Africa, such as Homo habilis ; the third is that it is Homo sapiens with pathology. We use parsimony and Bayesian phylogenetic methods to test these hypotheses. Our phylogenetic data build upon those characters previously presented in support of these hypotheses by broadening the range of traits to include the crania, mandibles, dentition, and postcrania of Homo and Australopithecus . The new data and analyses support the hypothesis that H. floresiensis is an early Homo lineage: H. floresiensis is sister either to H. habilis alone or to a clade consisting of at least H. habilis, H. erectus, Homo ergaster, and H. sapiens. A close phylogenetic relationship between H. floresiensis and H. erectus or H. sapiens can be rejected; furthermore, most of the traits separating H. floresiensis from H. sapiens are not readily attributable to pathology (e.g., Down syndrome). The results suggest H. floresiensis is a long-surviving relict of an early (>1.75 Ma) hominin lineage and a hitherto unknown migration out of Africa, and not a recent derivative of either H. erectus or H. sapiens . [ABSTRACT FROM AUTHOR]

In celebration of the 50th anniversary of the Journal of Human Evolution, we re-evaluate the fossil record for early Homo (principally Homo erectus , Homo habilis , and Homo rudolfensis) from early diversification and dispersal in the Early Pleistocene to the ultimate demise of H. erectus in the early Middle Pleistocene. The mid-1990s marked an important historical turning point in our understanding of early Homo with the redating of key H. erectus localities, the discovery of small H. erectus in Asia, and the recovery of an even earlier presence of early Homo in Africa. As such, we compare our understanding of early Homo before and after this time and discuss how the order of fossil discovery and a focus on anchor specimens has shaped, and in many ways biased, our interpretations of early Homo species and the fossils allocated to them. Fragmentary specimens may counter conventional wisdom but are often overlooked in broad narratives. We recognize at least three different cranial and two or three pelvic morphotypes of early Homo. Just one postcranial morph aligns with any certainty to a cranial species, highlighting the importance of explicitly identifying how we link specimens together and to species; we offer two ways of visualizing these connections. Chronologically and morphologically H. erectus is a member of early Homo , not a temporally more recent species necessarily evolved from either H. habilis or H. rudolfensis. Nonetheless, an ancestral–descendant notion of their evolution influences expectations around the anatomy of missing elements, especially the foot. Weak support for long-held notions of postcranial modernity in H. erectus raises the possibility of alternative drivers of dispersal. New observations suggest that the dearth of faces in later H. erectus may mask taxonomic diversity in Asia and suggest various later mid-Pleistocene populations could derive from either Asia or Africa. Future advances will rest on the development of nuanced ways to affiliate fossils, greater transparency of implicit assumptions, and attention to detailed life history information for comparative collections; all critical pursuits for future research given the great potential they have to enrich our evolutionary reconstructions for the next fifty years and beyond. [ABSTRACT FROM AUTHOR]

A completely new and unexpected quasi human species, Homo floresiensis, nicknamed the Hobbit, was described in 2004 from Liang Bua, a cave in Flores. Like many important new contributions to the human fossil record in the past, many commentators refused to believe that a new species had been discovered, and the type specimen was interpreted as a pathological modern human, usually as a microcephalic dwarf. There is no substance to these claims: close analysis shows that Homo floresiensis is not only a genuinely new species, but that its closest affinities lie with Plio-Pleistocene African species such as Homo habilis, so that it documents an earlier dispersal of hominins from Africa and had hitherto been suspected.

A fifth hominin skull (cranium D4500 and mandible D2600) from Dmanisi is massively constructed, with a large face and a very small brain. Traits documented for the first time in a basal member of the Homo clade include the uniquely low ratio of endocranial volume to basicranial width, reduced vertex height, angular vault profile, smooth nasal sill coupled with a long and sloping maxillary clivus, elongated palate, and tall mandibular corpus. The convex clivus and receding symphysis of skull 5 produce a muzzle-like form similar to that of Australopithecus afarensis . While the Dmanisi cranium is very robust, differing from OH 13, OH 24, and KNM-ER 1813, it resembles Homo habilis specimens in the “squared off” outline of its maxilla in facial view, maxillary sulcus, rounded and receding zygomatic arch, and flexed zygomaticoalveolar pillar. These characters distinguish early Homo from species of Australopithecus and Paranthropus . Skull 5 is unlike Homo rudolfensis cranium KNM-ER 1470. Although it appears generally primitive, skull 5 possesses a bar-like supraorbital torus, elongated temporal squama, occipital transverse torus, and petrotympanic traits considered to be derived for Homo erectus . As a group, the Dmanisi crania and mandibles display substantial anatomical and metric variation. A key question is whether the fossils document age-related growth and sex dimorphism within a single population, or whether two (or more) distinct taxa may be present at the site. We use the coefficient of variation to compare Dmanisi with Paranthropus boisei , H. erectus , and recent Homo sapiens , finding few signals that the Dmanisi sample is excessively variable in comparison to these reference taxa. Using cranial measurements and principal components analysis, we explore the proposal that the Dmanisi skulls can be grouped within a regionally diverse hypodigm for H. erectus. Our results provide only weak support for this hypothesis. Finally, we consider all available morphological and paleobiological evidence in an attempt to clarify the phyletic relationship of Dmanisi to Homo species evolving >2.0 to 1.0 Ma. [ABSTRACT FROM AUTHOR]

Before the appearance of Homo sapiens sapiens, some pre-human genotypes that lived on the Earth, left material evidence concerning different events of their social, behavioral or artistic manifestations. One of the earliest proofs is the use of objects from the environment as primitive tools to extract bone marrow, action probably achieved by a population of Australian leniencies in Romania (Teutonic, Beguileşti, Oltenia, about 2,000,000 BC). Current studies show that pre-human species originated in the African Rift Valley, which provided optimum benefits to its evolution and diversity. Proto-oceanic environmental quality and diet (rich source of polyunsaturated long fibres) ensured brain development and human evolution. Several pre-human species (Homo hails, HO. nailed, HO. erectus, etc.) emerged and lived in this area prior to their migration to other continents. Fire making and use, both for cooking and protection against weather and wildlife, was the essential factor for human evolution. Benefiting from the cooked food, pre-human beings had access to richer food resources, which led to the increase of the skeleton, and, implicitly, of the skull and encephala. This made possible the development of practical utilities, followed by abstract utilities, such as thinking and intelligence. Sexual dimorphism, the presence of the gene FOX-P 2 and the development of language, social and tribal life led to the arrangement of the living spaces, family. The increase of the skull and brain development contributed to the transition from practical activities (manufacture of weapons and tools) to abstract activities, development of art and intelligence. By abstract modeling of the materials from nature (rock, bone, ivory or wood) there were created statues, wall paintings, there appeared burial, cremation and embalming practices, which represented the germs of religion through the belief in the afterlife (in tombs, there were found food, personal items to be useful by the deceased persons at their return in another life). [ABSTRACT FROM AUTHOR]

Although the definition of intelligence is debatable, it can be allocated to only one anatomical location: the brain. Arguments regarding general measures of animal intelligence and discussions of its evolution up to the Neanderthals arise only because hominids have evolved to have larger brains; i.e., they have become more “intelligent”. Hominids clearly evolved in the past, but whether evolution is still ongoing is debated. Ironically, because hominids have created technologies and innovations to aid their survival, their evolution has included adaptation to the environment generated by their inventions. Similar to the recent evolution of ADHD traits or gluten tolerance, the hominid brain has undergone major changes over the past seven million years due to man-made habitats and technologies. Tool-making creates an environment conducive to increased social interactions, as it facilitates increased provisioning and protection, while increased opportunities for interactions and observations lead to advances in toolmaking. These changes have been offset by the concurrent evolution of language and tool-making. Biologically, hominid brains have increased in size in areas where toolmaking and language-processing coincide. This increase in brain size allowed advanced provisioning and tools, including the use of fire, and the technological advances during the Palaeolithic that stood on the shoulders of the previous evolutionary innovations of bipedalism and versatile hands enhanced the momentum of brain evolution. The beginnings of the reciprocal cause and effect between brain evolution and tool-making cannot be identified. The applicability of the hunting and fire hypotheses to the evolution of human intelligence is further discussed. [ABSTRACT FROM AUTHOR]

The estimation of body size among the earliest members of the genus Homo (2.4–1.5 Myr [millions of years ago]) is central to interpretations of their biology. It is widely accepted that Homo ergaster possessed increased body size compared with Homo habilis and Homo rudolfensis , and that this may have been a factor involved with the dispersal of Homo out of Africa. The study of taxonomic differences in body size, however, is problematic. Postcranial remains are rarely associated with craniodental fossils, and taxonomic attributions frequently rest upon the size of skeletal elements. Previous body size estimates have been based upon well-preserved specimens with a more reliable species assessment. Since these samples are small ( n < 5) and disparate in space and time, little is known about geographical and chronological variation in body size within early Homo . We investigate temporal and spatial variation in body size among fossils of early Homo using a ‘taxon-free’ approach, considering evidence for size variation from isolated and fragmentary postcranial remains ( n = 39). To render the size of disparate fossil elements comparable, we derived new regression equations for common parameters of body size from a globally representative sample of hunter-gatherers and applied them to available postcranial measurements from the fossils. The results demonstrate chronological and spatial variation but no simple temporal or geographical trends for the evolution of body size among early Homo . Pronounced body size increases within Africa take place only after hominin populations were established at Dmanisi, suggesting that migrations into Eurasia were not contingent on larger body sizes. The primary evidence for these marked changes among early Homo is based upon material from Koobi Fora after 1.7 Myr, indicating regional size variation. The significant body size differences between specimens from Koobi Fora and Olduvai support the cranial evidence for at least two co-existing morphotypes in the Early Pleistocene of eastern Africa. [ABSTRACT FROM AUTHOR]