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The modern human hand is an intriguing mix of primitive morphology and derived function. Traditionally, its form and function are explained as a functional "trade‐off" between the requirements of locomotion and manipulation, but recently acquired comparative, experimental and fossil evidence suggests that this functional trade‐off is more complex than conventional wisdom suggests. Moreover, when studying hand evolution within the hominin clade, the only morphological evidence comes from the hard‐tissues, and evidence about hand function must be inferred indirectly from the archaeological record. We lack information about critical aspects of hand form (e.g., soft tissues) and function (e.g., neurology) as well as non‐lithic evidence about behavior. Thus, comparative anatomical, experimental and ethological studies of modern humans and other primates are critical to making more informed inferences about hand use in the past. We review the relevant fossil and archaeological evidence within the relevant comparative context (e.g., other extant apes and dexterous monkeys) in an attempt to reconstruct hand evolution within the hominin clade. We conclude by summarizing our current understanding—or lack thereof—of the evolutionary history of the modern human hand. [ABSTRACT FROM AUTHOR]

Body mass is a critical variable in many hominin evolutionary studies, with implications for reconstructing relative brain size, diet, locomotion, subsistence strategy, and social organization. We review methods that have been proposed for estimating body mass from true and trace fossils, consider their applicability in different contexts, and the appropriateness of different modern reference samples. Recently developed techniques based on a wider range of modern populations hold promise for providing more accurate estimates in earlier hominins, although uncertainties remain, particularly in non‐Homo taxa. When these methods are applied to almost 300 Late Miocene through Late Pleistocene specimens, the resulting body mass estimates fall within a 25–60 kg range for early non‐Homo taxa, increase in early Homo to about 50–90 kg, then remain constant until the Terminal Pleistocene, when they decline. [ABSTRACT FROM AUTHOR]

Yet, despite his call for a more speciose interpretation of early I Homo i , in the illustration early in the book illustrating fossil hominin species through time, Tattersall lumps all the eastern African early I Homo i fossils into a single species. Despite the prodigious efforts of field researchers, the fossil evidence we have now (i.e. the "known fossil record" sensu [1]) is almost certainly much less informative about taxic diversity, geographical range, and temporal span, than the fossil record we imagined in our thought experiment. Researchers who recently tried to estimate the impact of rock availability and collection effort on the first and last appearances of early fossil hominin taxa came to the conclusion that these two factors likely had a profound influence on whether a taxon left an accessible fossil record ([4]). There are cases when one new fossil (e.g. OH 7, the type specimen of I Homo habilis i from Olduvai [now Oldupai] Gorge in Tanzania) is so different from the existing fossil evidence at a site (e.g. OH 5, the type specimen of I Paranthropus boisei i , also from Olduvai Gorge) that the case for taxonomic distinctiveness is obvious, but not many claims for new hominin taxa are as securely based as this example. [Extracted from the article]

The research agenda of paleoanthropology involves many topics and methodologies. Fossil specimens are allocated to species, and those species are assigned to the hominin clade. After that we want to know how they are related to each other, what they ate, how much they weighed, how smart they were, etc. We also want to know about the origin of particular attributes of hominins, such as our delayed growth and development, bipedalism, and language. The data available to answer these complex questions are confounded by fragmentary fossil specimens, small sample sizes, limited opportunities for controlled experimentation, and the inherent limitations of historical data. Also, because many traits are effectively unique to hominins, even observational comparative studies are inevitably limited in what they can tell us, if not impossible to conduct. We explore how these limitations should, but often do not, constrain the questions that paleoanthropologists should attempt to answer. [ABSTRACT FROM AUTHOR]

The inhibitory cascade is a mathematical model for interpreting the relative size of the occlusal surfaces of mammalian molars in terms of developmental mechanisms. The cascade is derived from experimental studies of mouse molars developed in culture, and has been tested and applied to the dentitions of rodents, ungulates, carnivores, and platyrrhines. Results from such applications have provided new information regarding the origins of plesiomorphic traits in mammalian clade and how derived morphologies may arise. In this study we apply the inhibitory cascade model to the postcanine dentition of a sample of Old World primates that includes fossil hominins. The results of this study suggest that the inhibitory cascade (i.e. M1 < M2 < M3) describes the relative sizes of the molar occlusal areas of Old World primates and is likely the plesiomorphic condition for this clade. Within that clade, whereas most Old World monkeys have a M1 < M2 < M3 pattern, most apes have a M1 < M2 ≈ M3 pattern. This modified cascade suggests that greater levels of inhibition (or less activation) are acting on the posterior molars of apes, thus facilitating the reduction of M3s within the apes. With the exception of the baboon genus Papio, extant congeners typically share the same molar inhibitory cascade. The differences in the relative size relationships observed in the molar and premolar-molar cascades of the species included in the fossil hominin genus Paranthropus suggest that although large postcanine teeth are a shared derived trait within this genus, the developmental basis for postcanine megadontia may not be the same in these two Paranthropus taxa. Our results show that phenotypic characters such as postcanine megadontia may not reflect common development. [ABSTRACT FROM AUTHOR]

Despite uncontested evidence for fossils belonging to the early hominin genus Australopithecus in East Africa from at least 4.2 million years ago (Ma), and from Chad by 3.5 Ma, thus far there has been no convincing evidence of Australopithecus, Paranthropus or early Homo from the western (Albertine) branch of the Rift Valley. Here we report the discovery of an isolated upper molar (#Ish25) from the Western Rift Valley site of Ishango in Central Africa in a derived context, overlying beds dated to between ca. 2.6 to 2.0 Ma. We used µCT imaging to compare its external and internal macro-morphology to upper molars of australopiths, and fossil and recent Homo. We show that the size and shape of the enamel-dentine junction (EDJ) surface discriminate between Plio-Pleistocene and post-Lower Pleistocene hominins, and that the Ishango molar clusters with australopiths and early Homo from East and southern Africa. A reassessment of the archaeological context of the specimen is consistent with the morphological evidence and suggest that early hominins were occupying this region by at least 2 Ma. [ABSTRACT FROM AUTHOR]

Carbon isotope studies of early hominins from southern Africa showed that their diets differed markedly from the diets of extant apes. Only recently, however, has a major influx of isotopic data from eastern Africa allowed for broad taxonomic, temporal, and regional comparisons among hominins. Before 4 Ma, hominins had diets that were dominated by C3 resources and were, in that sense, similar to extant chimpanzees. By about 3.5 Ma, multiple hominin taxa began incorporating 13C-enriched [C4 or crassulacean acid metabolism (CAM)] foods in their diets and had highly variable carbon isotope compositions which are atypical for African mammals. By about 2.5 Ma, Paranthropus in eastern Africa diverged toward C4/CAM specialization and occupied an isotopic niche unknown in catarrhine primates, except in the fossil relations of grass-eating geladas (Theropithecus gelada). At the same time, other taxa (e.g., Australopithecus africanus) continued to have highly mixed and varied C3/C4 diets. Overall, there is a trend toward greater consumption of 13C-enriched foods in early hominins over time, although this trend varies by region. Hominin carbon isotope ratios also increase with postcanine tooth area and mandibular cross-sectional area, which could indicate that these foods played a role in the evolution of australopith masticatory robusticity. The 13C-enriched resources that hominins ate remain unknown and must await additional integration of existing paleodietary proxy data and new research on the distribution, abundance, nutrition, and mechanical properties of C4 (and CAM) plants. [ABSTRACT FROM AUTHOR]

Here we provide the first report about the rates of muscle evolution derived from Bayesian and parsimony cladistic analyses of primate higher-level phylogeny, and compare these rates with published rates of molecular evolution. It is commonly accepted that there is a 'general molecular slow-down of hominoids', but interestingly the rates of muscle evolution in the nodes leading and within the hominoid clade are higher than those in the vast majority of other primate clades. The rate of muscle evolution at the node leading to Homo (1.77) is higher than that at the nodes leading to Pan (0.89) and particularly to Gorilla (0.28). Notably, the rates of muscle evolution at the major euarchontan and primate nodes are different, but within each major primate clade (Strepsirrhini, Platyrrhini, Cercopithecidae and Hominoidea) the rates at the various nodes, and particularly at the nodes leading to the higher groups (i.e. including more than one genera), are strikingly similar. We explore the implications of these new data for the tempo and mode of primate and human evolution. [ABSTRACT FROM AUTHOR]

This contribution reviews the evidence that has resolved the branching structure of the higher primate part of the tree of life and the substantial body of fossil evidence for human evolution. It considers some of the problems faced by those who try to interpret the taxonomy and systematics of the human fossil record. How do you to tell an early human taxon from one in a closely related dade? How do you determine the number of taxa represented in the human dade? How can homoplasy be recognized and factored into attempts to recover phylogeny? [ABSTRACT FROM AUTHOR]

The article presents a study which reviewed the evolutionary history of Paranthropus (P.) boisei, a hominin taxon with a distinctive cranial and dental morphology, from 1957 through 2007. The reasons why P. boisei is unusual among hominins include it is an easily recognized taxon and most of P. boisei comes from sites with stratigraphic and chronological control. Topics discussed include geographic and temporal range, the hypodigm of P. boisei and debates concerning the taxonomy of P. boisei.

Presents evidence for the emergence of hominids for changes in human evolution and for the major stages in human evolution. Exploration of crucial innovations to changes in climate; Differences between apes and humans; Description of Australopithecines and Paranthropus.

Presents a systematic attempt to reconstruct the evolutionary history of the bipedalism of modern humans. Locomotor behavior of early hominids; Examination of the vestibular system of living primates and early hominids; Cranial semicircular canals.

Focuses on studies on primate development and growth and its bearing on the interpretation of the course of human evolution. Evolutionary context of comparative growth studies of primates; Comparisons and contrasts of aspects of the ontogeny of living modern humans and chimpanzees; Heterochromic changes in primates.

Discusses the Taung skull discovered by Raymond Dart in Africa and its connection with the diversity in the structure of early hominids. Comparison of the Taung skull and the fossil cranium found by Michel Brunet and his colleagues; Description of the skeletal structure of the early hominids; Chart showing the evolution of ape-like creatures to human.

Summary Modern humans originated in Africa, but where exactly? So far, East Africa harbored the oldest fossil and archaeological evidence. Now, fossils and stone tools from a cave in Morocco challenge the notion that East Africa was the birthplace of modern humans. [ABSTRACT FROM AUTHOR]

Discusses developments in molecular biology that have made available a new generation of molecular markers that can record events in the evolution of Homo sapiens that cannot be detected with conventional methods as of November 13, 1997. What the first attempts to recover what Darwin called the `perfect pedigree of mankind.'

Discusses the discovery in the Awash Valley of Ethiopia of the fossil remains of Australopithecus ramidus. Designation as the oldest hominid species; Background information; Geological context; Paleogeographic reconstruction of area; Characterization of remains; Implications to theories on human evolution.

Recent analyses and new fossil discoveries suggest that the evolution of hominin limb length proportions is complex, with evolutionary reversals and a decoupling of proportions within and between limbs. This study takes into account intraspecific variation to test whether or not the limb proportions of four early hominin associated skeletons (AL 288-1, OH 62, BOU-VP-12/1, and KNM-WT 15000) can be considered to be significantly different from one another. Exact randomization methods were used to compare the differences between pairs of fossil skeletons to the differences observed between all possible pairs of individuals within large samples of Gorilla gorilla, Pan troglodytes, Pongo pygmaeus, and Homo sapiens. Although the difference in humerofemoral proportions between OH 62 and AL 288-1 does not exceed variation in the extant samples, it is rare. When humerofemoral midshaft circumferences are compared, the difference between OH 62 and AL 288-1 is fairly common in extant species. This, in combination with error associated with the limb lengths estimates, suggests that it may be premature to consider H. (or Australopithecus) habilis as having more apelike limb proportions than those in A. afarensis. The humerofemoral index of BOU-VP-12/1 differs significantly from both OH 62 and AL 288-1, but not from KNM-WT 15000. Published length estimates, if correct, suggest that the relative forearm length of BOU-VP-12/1 is unique among hominins, exceeding those of the African apes and resembling the proportions in Pongo.Evidence that A. afarensis exhibited a less apelike upper:lower limb design than A. africanus (and possibly H. habilis) suggests that, if A. afarensis is broadly ancestral to A. africanus, the latter did not simply inherit primitive morphology associated with arboreality, but is derived in this regard. The fact that the limb proportions of OH 62 (and possibly KNM-ER 3735) are no more humanlike than those of AL 288-1 underscores the primitive body design of H. habilis. [Copyright &y& Elsevier]

A central goal of paleoanthropology is understanding the role of ecological change in hominin evolution. Over the past several decades researchers have expanded the hominin fossil record and assembled detailed late Cenozoic paleoclimatic, paleoenvironmental, and paleoecological archives. However, effective use of these data is precluded by the limitations of pattern-matching strategies for inferring causal relationships between ecological and evolutionary change. We examine several obstacles that have hindered progress, and highlight recent research that is addressing them by (i) confronting an incomplete fossil record, (ii) contending with datasets spanning varied spatiotemporal scales, and (iii) using theoretical frameworks to build stronger inferences. Expanding on this work promises to transform challenges into opportunities and set the stage for a new phase of paleoanthropological research. Research aiming to understand the role of ecological change in hominin evolution has fueled the generation of paleoclimatic and paleoenvironmental records across Africa. Limitations of conventional methods for inferring ecology–evolution relationships mean that more data have not always led to a deeper understanding of hominin evolution. We outline several challenges that have hindered progress, and highlight how recent research is addressing them. This research is confronting the limitations of the fossil record, contending with proxy records spanning a range of spatiotemporal scales, and providing a stronger inferential approach to hypothesis testing. Addressing the obstacles that have hindered progress will enable a more robust understanding of the relationships between ecological change and hominin evolution. [ABSTRACT FROM AUTHOR]

We are in a new epoch, the Anthropocene, and research into our closest living relatives, the great apes, must keep pace with the rate that our species is driving change. While a goal of many studies is to understand how great apes behave in natural contexts, the impact of human activities must increasingly be taken into account. This is both a challenge and an opportunity, which can importantly inform research in three diverse fields: cognition, human evolution, and conservation. No long-term great ape research site is wholly unaffected by human influence, but research at those that are especially affected by human activity is particularly important for ensuring that our great ape kin survive the Anthropocene. [ABSTRACT FROM AUTHOR]