Hominin Species Research Articles

Environmental Reconstruction from the Identification of Magnetic Minerals in the Upper Sedimentary Infill of the Gran Dolina Cave (Burgos, Spain)

The cave system in the Sierra de Atapuerca holds one of the most important archaeological sites for the understanding of early human occupation in Europe. Among the different cavities and galleries, the Gran Dolina cave yielded a new hominin species coined as Homo antecessor of an Early Pleistocene age. Encouraged by our previous results in Gran Dolina, we carried out a study to extend and deepen our rockmagnetic investigation of the paleoenvironmental reconstruction of the upper Gran Dolina cave based on experiments that include composition, relative concentration, and grain size of the magnetic iron oxides present in the sediments. Based on the rockmagnetic experiments, we identified magnetite, hematite, goethite, and possibly maghemite in changeable amounts along the profile, which allows us to complement the existing shortage in the literature on the palaeoenvironmental reconstruction of the site. We tentatively interpret the rockmagnetic changes recorded in the cave sediments in terms of glacial/interglacial conditions, furnishing the base for a better understanding for the formation conditions of this unprecedented archaeological site.

About this title - Quaternary Geoarchaeology of India

The Quaternary Period in South Asia has a very prolonged and diverse history. Within this region, India represents various technological and cultural phases of hominin occupation adapting to different ecological zones throughout the Quaternary Period. The earliest records of this occupation can be traced back to 1.5 Ma ago and possibly to c . 2 Ma ago. Archaeological evidence has been reported from all known phases in India, showing a continuous record of occupation from the Early Pleistocene onwards and reflecting adaptation by multiple hominin species over time. This book aims to highlight recent advances in the Quaternary geoarchaeology by showcasing diverse methods such as archaeology, geology, palaeoclimatology, sedimentology, GIS, remote sensing and taphonomy. It presents a collection of papers that address various geoarchaeological aspects from different regions in India, within the time frame of the Early Pleistocene to Anthropocene. This volume provides an opportunity for new data to be disseminated, particularly by young researchers and, within the framework of worldwide research issues, it promotes new geoarchaeological perspectives from India.

Defining paleoclimatic routes and opportunities for hominin dispersals across Iran.

Fossil and archaeological evidence indicates that hominin dispersals into Southwest Asia occurred throughout the Pleistocene, including the expansion of Homo sapiens populations out of Africa. While there is evidence for hominin occupations in the Pleistocene in Iran, as evidenced by the presence of Lower to Upper Paleolithic archaeological sites, the extent to which humid periods facilitated population expansions into western Asia has remained unclear. To test the role of humid periods on hominin dispersals here we assess Paleolithic site distributions and paleoenvironmental records across Iran. We developed the first spatially comprehensive, high-resolution paleohydrological model for Iran in order to assess water availability and its influence on hominin dispersals. We highlight environmentally mediated routes which likely played a key role in Late Pleistocene hominin dispersals, including the expansion of H. sapiens and Neanderthals eastwards into Asia. Our combined analyses indicate that, during MIS 5, there were opportunities for hominins to traverse a northern route through the Alborz and Kopet Dagh Mountains and the Dasht-I Kavir desert owing to the presence of activated fresh water sources. We recognize a new southern route along the Zagros Mountains and extending eastwards towards Pakistan and Afghanistan. We find evidence for a potential northern route during MIS 3, which would have permitted hominin movements and species interactions in Southwest Asia. Between humid periods, these interconnections would have waned, isolating populations in the Zagros and Alborz Mountains, where hominins may have continued to have had access to water.

Modelling Neanderthals' dispersal routes from Caucasus towards east.

The study of the cultural materials associated with the Neanderthal physical remains from the sites in the Caucasus, Central Asia and Siberian Altai and adjacent areas documents two distinct techno-complexes of Micoquian and Mousterian. These findings potentially outline two dispersal routes for the Neanderthals out of Europe. Using data on topography and Palaeoclimate, we generated computer-based least-cost-path modelling for the Neanderthal dispersal routes from Caucasus towards the east. In this regard, two dispersal routes have been identified: A northern route from Greater Caucasus associated with Micoquian techno-complex towards Siberian Altai and a southern route from Lesser Caucasus associated with Mousterian towards Siberian Altai via the Southern Caspian Corridor. Based on archaeological, bio- and physio-geographical data, our model hypothesises that during climatic deterioration phases (e.g. MIS 4) the connection between Greater and Lesser Caucasus was limited. This issue perhaps resulted in the separate development and spread of two cultural groups of Micoquian and Mousterian with an input from two different population sources of Neanderthal influxes: eastern and southern Europe refugia for these two northern and southern dispersal routes respectively. Of these two, we focus on the southern dispersal route, for it comprises a 'rapid dispersal route' towards east. The significant location of the Southern Caspian corridor between high mountains of Alborz and the Caspian Sea, provided a special biogeographical zone and a refugium. This exceptional physio-geographic condition brings forward the Southern Caspian corridor as a potential place of admixture of different hominin species including Neanderthals and homo sapiens.

Changing perspectives on early hominin diets

It is axiomatic that knowledge of the diets of extinct hominin species is central to any understanding of their ecology and our evolution. The importance of diet in the paleontological realm has led to the employment of multiple approaches in its elucidation. Some of these have deep historical roots, while others are dependent upon more recent technical and methodological advances. Historically, studies of tooth size, shape, and structure have been the gold standard for reconstructing diet. They focus on species-level adaptations, and as such, they can set theoretical brackets for dietary capabilities within the context of specific evolutionary moments. Other methods (e.g., analyses of dental calculus, biogeochemistry, and dental microwear) have only been developed within the past few decades, but are now beginning to yield evidence of the actual foods consumed by individuals represented by fossil remains. Here we begin by looking at these more “direct” forms of evidence of diet before showing that, when used in conjunction with other techniques, these “multi-proxy” approaches can raise questions about traditional interpretations of early hominin diets and change the nature of paleobiological interpretations.

Intersubjectivity, Empathy, Life‐World, and the Social Brain: The Relevance of Husserlian Neurophenomenology for the Anthropology of Consciousness

AbstractOur species of hominin, Homo sapiens, is an extremely social animal. We are born with social brains. The phenomenology of Edmund Husserl is a methodological approach to social consciousness that offers significant advantages in terms of uncovering and describing the essential structures of our social perceptions and actions. This is especially true in this period of post‐neuro‐turn social science, because the structures described by Husserlian “pure” phenomenology with its emphasis upon “returning to the things,” performing reductions, and developing the skills available to the phenomenological attitude are in synch with neuroscientific research on the neural correlates of consciousness. For the anthropology of consciousness, the Husserlian methodology allows us to explore consciousness in cross‐cultural settings in greater detail and depth of understanding. This is especially the case with respect to the experience of intersubjectivity, the roots of which are found to be part of the inherent life‐world that all normal humans depend upon to true their experiences of the environing world, regardless of cultural background. The Husserlian approach to intersubjectivity challenges the discipline of anthropology to move past its knee‐jerk distinction between nature and nurture, and its erroneous assumption that human experience is somehow “culture all the way down.”

Human Genetic Research in Wallacea and Sahul: Recent Findings and Future Prospects.

Genomic sequence data from worldwide human populations have provided a range of novel insights into our shared ancestry and the historical migrations that have shaped our global genetic diversity. However, a comprehensive understanding of these fundamental questions has been impeded by the lack of inclusion of many Indigenous populations in genomic surveys, including those from the Wallacean archipelago (which comprises islands of present-day Indonesia located east and west of Wallace's and Lydekker's Lines, respectively) and the former continent of Sahul (which once combined New Guinea and Australia during lower sea levels in the Pleistocene). Notably, these regions have been important areas of human evolution throughout the Late Pleistocene, as documented by diverse fossil and archaeological records which attest to the regional presence of multiple hominin species prior to the arrival of anatomically modern human (AMH) migrants. In this review, we collate and discuss key findings from the past decade of population genetic and phylogeographic literature focussed on the hominin history in Wallacea and Sahul. Specifically, we examine the evidence for the timing and direction of the ancient AMH migratory movements and subsequent hominin mixing events, emphasising several novel but consistent results that have important implications for addressing these questions. Finally, we suggest potentially lucrative directions for future genetic research in this key region of human evolution.

The game of models: Dietary reconstruction in human evolution

Despite substantial additions to the paleontological record and unanticipated improvements in analytical techniques since the Journal of Human Evolution was first published, consensus on the diet of early hominin species remains elusive. For instance, the notable advances in the analyses of hominin dental microwear and stable isotopes have provided a plethora of data that have in some instances clouded what was once ostensibly a clear picture of dietary differentiation between and within hominin taxa. In the present study, we explore the reasons why the retrodiction of diet in human evolution has proven vexing over the last half century from the perspective of both ecological and functional-mechanical models. Such models continue to be indispensable for paleobiological reconstructions, but they often contain rigid or unstated assumptions about how primary paleontological data, such as fossils and their geological and taphonomic contexts, allow unambiguous insight into the evolutionary processes that produced them. In theoretical discussions of paleobiology, it has long been recognized that a mapping function of morphology to adaptation is not one-to-one, in the sense that a particular trait cannot necessarily be attributed to a specific selective pressure and/or behavior. This article explores how the intrinsic variability within biological systems has often been underappreciated in paleoanthropological research. For instance, to claim that derived anatomical traits represent adaptations related to stereotypical behaviors largely ignores the importance of biological roles (i.e., how anatomical traits function in the environment), a concept that depends on behavioral flexibility for its potency. Similarly, in the paleoecological context, the underrepresentation of variability within the ‘edible landscapes’ our hominin ancestors occupied has inhibited an adequate appreciation of early hominin dietary flexibility. Incorporating the reality of variation at organismal and ecological scales makes the practice of paleobiological reconstruction more challenging, but in return, allows for a better appreciation of the evolutionary possibilities that were open to early hominins.

Teaching as evolutionary precursor to language

The central thesis of this article is that the evolution of teaching is one of the main factors that lead to increasingly complex communicative systems in the hominin species. Following earlier analyses of the evolution of teaching, the following steps are identified: (i) evaluative feedback, (ii) drawing attention, (iii) demonstration and pantomime, (iv) communicating concepts, (v) explaining relations between concepts, and (vi) narrating. For each of these step the communicative and cognitive demands will be analyzed. The focus will be on demonstration and pantomime, since these seem to be the evolutionarily earliest unique human capacities. An important step is the transition from pantomime for teaching to pantomime for informing and how this in turn leads to communicating concepts. As regards explaining relations between concepts, the focus will be of the role of generics in teaching and communication. Analyzing these topics involves combining cognitive science with evolutionary theory, archaeology and theories of communication. Two factors are important as a background: (i) the evolution of prospective planning, that is, planning for future goals, and (ii) the evolution of a theory mind. These capacities are central in explaining how more advanced forms of teaching, communication and cooperation emerged along the hominin line.

Frontal sinuses and human evolution.

The frontal sinuses are cavities inside the frontal bone located at the junction between the face and the cranial vault and close to the brain. Despite a long history of study, understanding of their origin and variation through evolution is limited. This work compares most hominin species’ holotypes and other key individuals with extant hominids. It provides a unique and valuable perspective of the variation in sinuses position, shape, and dimensions based on a simple and reproducible methodology. We also observed a covariation between the size and shape of the sinuses and the underlying frontal lobes in hominin species from at least the appearance of Homo erectus. Our results additionally undermine hypotheses stating that hominin frontal sinuses were directly affected by biomechanical constraints resulting from either chewing or adaptation to climate. Last, we demonstrate their substantial potential for discussions of the evolutionary relationships between hominin species.

Laughter and its role in the evolution of human social bonding.

In anthropoid primates, social grooming is the principal mechanism (mediated by the central nervous system endorphin system) that underpins social bonding. However, the time available for social grooming is limited, and this imposes an upper limit on the size of group that can be bonded in this way. I suggest that, when hominins needed to increase the size of their groups beyond the limit that could be bonded by grooming, they co-opted laughter (a modified version of the play vocalization found widely among the catarrhine primates) as a form of chorusing to fill the gap. I show, first, that human laughter both upregulates the brain's endorphin system and increases the sense of bonding between those who laugh together. I then use a reverse engineering approach to model group sizes and grooming time requirements for fossil hominin species to search for pinch points where a phase shift in bonding mechanisms might have occurred. The results suggest that the most likely time for the origin of human-like laughter is the appearance of the genus Homo ca 2.5 Ma.This article is part of the theme issue ‘Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience’.

Technological Lithic Production Variability of the Teshik-Tash Grotto Industry

Purpose. For the Central Asian territories, only the discovery of a burial from Teshik-Tash has an indisputable connection with the Neanderthal population confirmed by genetic studies. In this situation, it is important to fully characterize the technological repertoire of this hominin species through a detailed study of the lithic industry of TeshikTash. One of the parts of the Teshik-Tash collection, kept in the collections of the Kunstkamera (St. Petersburg, Russia), was previously analyzed. Observations regarding the operation of radial and disc-shaped cores at the late stages of utilization, as well as the identified features in the morphology of points, again identified the problem of the presence / absence of the Levallois component in the Teshik-Tash industry.Materials and Methods. Attributive analysis was chosen as a research tool, which was previously applied to the collection from the Kunstkamera. It allows reconstructing the entire “operational chain” of knapping lithic raw materials at the site and identifying the technological features of the production of different types of blanks.Results. The performed analysis allows identifying some features of the knapping technology in the Teshik-Tash industry, such as: the dominant knapping system is centripetal; the using of Levallois technology is recorded in the one core; a method of shaping the core front by creating a rib at the base and using lateral spalls; a case of the volumetric concept of knapping has been identified; the strategies used in the industry resulted in a low standardized product; the rare design of percussion platforms and their reduction. The tool kit is characterized by the using of cores as the tools; the presence of two groups of “special purpose” tools; the irregularly retouched flakes as a background tool category; the presence of truncated and truncated-faceted pieces.Discussion. The knapping approach was quite flexible, and this implies the possibility of switching from one model to another at different stages of core utilization. For this reason, some cores fall into the “grey zone” between radial, discoid, and Levallois types. At the same time, the Levallois technique occupies a clearly subordinate position in the industry, was extremely rarely used in the early stages of core utilization, and had almost no effect on the overall appearance of blanks. For this reason, we believe that Levallois technique should be considered as a one of the significant characteristics of the Teshik-Tash industry with great caution, as well as direct analogies with the new Middle Paleolithic complexes of the Tien Shan low mountains.Conclusion. The processing of the Teshik-Tash collection made it possible to fix the dominance of the centripetal model of lithic knapping, the use of which is imprinted in the morphology of products of all main categories. At the same time, a number of artifacts point to the existence of technological variability in lithic production in the industry, both at the stage of making blanks (the use of sub-wedge-shaped and volumetric cores) and at the stage of designing tools (truncated-faceted products). These circumstances expand our understanding of the behavioral characteristics of the Neanderthals who lived in the west of Central Asia.

The relative limb size of Homonaledi

Homo erectus s.l. is key for deciphering the origin and subsequent evolution of genus Homo. However, the characterization of this species is hindered by the existence of multiple variants in both mainland and insular Asia, as a result of divergent chronogeographical evolutionary trends, genetic isolation, and interbreeding with other human species. Previous research has shown that cochlear morphology embeds taxonomic and phylogenetic information that may help infer the phylogenetic relationships among hominin species. Here we describe the cochlear morphology of two Indonesian H. erectus individuals (Sangiran 2 and 4), and compare it with a sample of australopiths, Middle to Late Pleistocene humans, and extant humans by means of linear measurements and both principal components and canonical variates analyses performed on shape ratios. Our results indicate that H. erectus displays a mosaic morphology that combines plesiomorphic (australopithlike) features (such as a chimplike round cochlear cross section and low cochlear thickness), with derived characters of later humans (a voluminous and long cochlea, possibly related to hearing abilities)—consistent with the more basal position of H. erectus. Our results also denote substantial variation between the two studied individuals, particularly in the length and radius of the first turn, as well as cross-sectional shape. Given the small size of the available sample, it is not possible to discern whether such differences merely reflect intraspecific variation among roughly coeval H. erectus individuals or whether they might result from greater age differences between them than currently considered. However, our results demonstrate that most characters found in later humans were already present in Indonesian H. erectus, with the exception of Neanderthals, which display an autapomorphic condition relative to other Homo species.

New fossils from Kromdraai and Drimolen, South Africa, and their distinctiveness among Paranthropus robustus

Most fossil hominin species are sampled with spatial, temporal or anatomical biases that can hinder assessments of their paleodiversity, and may not yield genuine evolutionary signals. We use new fossils from the Kromdraai (Unit P) and Drimolen sites (South Africa) to provide insights into the paleodiversity of the Lower Pleistocene robust australopith, Paranthropus robustus. Our focus is the morphology of the temporal bone and the relationships between size and shape (allometry) of the semi-circular canals (SCC), an aspect that has not yet been investigated among southern African australopiths. We find significant size and shape SCC differences between P. robustus from Kromdraai, Drimolen and Swartkrans. This site-related variation is consistent with other differences observed on the temporal bone. P. robustus from Kromdraai Unit P is distinctive because of its smaller temporal bone and SCC, and its proportionally less developed posterior SCC, independently of age and sex. We emphasize the importance of allometry to interpret paleodiversity in P. robustus as either the consequence of differences in body size, or as yet unknown factors. Some features of the inner ear of P. robustus represent directional selection soon after its origin, whereas the size and shape variations described here may result from evolutionary changes.

About this title - Quaternary Geoarchaeology of India

The Quaternary Period in South Asia has a very prolonged and diverse history. Within this region, India represents various technological and cultural phases of hominin occupation adapting to different ecological zones throughout the Quaternary Period. The earliest records of this occupation can be traced back to 1.5 Ma ago and possibly to c . 2 Ma ago. Archaeological evidence has been reported from all known phases in India, showing a continuous record of occupation from the Early Pleistocene onwards and reflecting adaptation by multiple hominin species over time. This book aims to highlight recent advances in the Quaternary geoarchaeology by showcasing diverse methods such as archaeology, geology, palaeoclimatology, sedimentology, GIS, remote sensing and taphonomy. It presents a collection of papers that address various geoarchaeological aspects from different regions in India, within the time frame of the Early Pleistocene to Anthropocene. This volume provides an opportunity for new data to be disseminated, particularly by young researchers and, within the framework of worldwide research issues, it promotes new geoarchaeological perspectives from India.

Muddying the muddle in the middle even more.

In an Evolutionary Anthropology article Roksandic et al. (2022) propose a new middle Pleistocene hominin species H. bodoensis to replace a "poorly defined" Homo heidelbergenis. Homo bodoensis extends from the African Middle Pleistocene through the Levant to South-eastern Europe with all currently classified H. heidelbergensis fossils from western Europe subsumed into Homo neandertalensis. The authors claim their new species will be more clearly defined than H. heidelbergensis and will better describe hominin variation and evolution in the middle Pleistocene. Roksandic et al. are unable to account for some European fossils (i.e., Petralona and Arago) and provide no evidence as to how their new species meets their objectives. Fatally, they overlook the priority rule and fail to realize that H. bodoensis is both a junior synonym of Homo rhodesiensis and Homo saldanensis. Roksandic et al. conflate taxonomy with phylogeny, present hypotheses as facts, and harbor many systematic and evolutionary misconceptions.

Morphological variation of the maxilla in modern humans and African apes

Differences in morphology among modern humans and African apes are frequently used when assessing whether hominin fossils should be attributed to a single species or represent evidence for taxic diversity. A good understanding of the degree and structure of the intergeneric, interspecific, and intraspecific variation, including aspects such as sexual dimorphism and age, are key in this context. Here we explore the variation and differences shown by the maxilla of extant hominines, as maxillary morphology is central in the diagnosis of several hominin taxa. Our sample includes adults of all currently recognized hominine species and subspecies, with a balanced species sex ratio. In addition, we compared the adults with a small sample of late juveniles. The morphology of the maxillae was captured using three-dimensional landmarks, and the size and shape were analyzed using geometric morphometric methods. Key observations are that 1) the maxillae of all extant hominine species and subspecies show statistically significant differences, but complete separation in shape is only seen at the genus level; 2) the degree of variation is not consistent between genera, with subspecies of Gorilla being more different from each other than are species of Pan; 3) the pattern of sexual shape dimorphism is different in Pan, Gorilla, and Homo, often showing opposite trends; and 4) differentiation between maxillary shapes is increased after adjustment for static intraspecific allometry. These results provide a taxonomically up-to-date comparative morphological framework to help interpret the hominin fossil record, and we discuss the practical implications in that context.

Making the Human Face: Elucidating the Role of Enhancers in Hominid Craniofacial Evolution

There is increasing evidence that morphological differences among individuals of the same species and between species are driven by changes in gene expression mediated by non‐coding mutations that are enriched at enhancer elements. The identification and comparative evaluation of these cis‐regulatory variants specific to human facial morphology have been facilitated by several recent advances. Among these are access to high‐quality genome sequences, especially from archaic hominins such as the Neanderthals, by expanded catalogs of SNPs implicated in normal range human facial variation from Genome‐wide Association Studies (GWAS), and by the curation of active human and chimp Cranial Neural Crest Cell (CNCC) enhancers that are important for facial development. To identify functional variants that mediate change in enhancer activity in recent human evolution and normal range variation and to nominate their target genes we employed two methods: (1) STARR‐seq, an enhancer reporter assay that permits accurate, comparative analysis of regulatory activity across enhancer homologs and their constituent cis‐mutations, and (2) H3K27ac HiChIP, a method to characterize the three‐dimensional interactome between enhancers and their target genes.We performed STARR‐seq and HiChIP experiments in the in vitro derived CNCCs, and early proliferative cranial chondrocytes. Comparisons of enhancer activity among the orthologs present in homo‐ or hominin species uncovered several classes of enhancers with species‐ or clade‐ restricted activity. Furthermore, for enhancers associated with facial shape GWAS signals, we identified genetic variants associated with changes in regulatory activity. By incorporating HiChIP labeled target genes, we found that biased intra‐species and GWAS enhancer homologs target important developmental transcription factors and signaling molecules. Our experiments have begun to provide insights into how evolutionarily important and functionally relevant enhancer cis‐variants can modulate gene regulatory programs at the individual‐ or species‐centric level with an outcome on facial phenotypes.

Climate effects on archaic human habitats and species successions

It has long been believed that climate shifts during the last 2 million years had a pivotal role in the evolution of our genus Homo1–3. However, given the limited number of representative palaeo-climate datasets from regions of anthropological interest, it has remained challenging to quantify this linkage. Here, we use an unprecedented transient Pleistocene coupled general circulation model simulation in combination with an extensive compilation of fossil and archaeological records to study the spatiotemporal habitat suitability for five hominin species over the past 2 million years. We show that astronomically forced changes in temperature, rainfall and terrestrial net primary production had a major impact on the observed distributions of these species. During the Early Pleistocene, hominins settled primarily in environments with weak orbital-scale climate variability. This behaviour changed substantially after the mid-Pleistocene transition, when archaic humans became global wanderers who adapted to a wide range of spatial climatic gradients. Analysis of the simulated hominin habitat overlap from approximately 300–400 thousand years ago further suggests that antiphased climate disruptions in southern Africa and Eurasia contributed to the evolutionary transformation of Homo heidelbergensis populations into Homo sapiens and Neanderthals, respectively. Our robust numerical simulations of climate-induced habitat changes provide a framework to test hypotheses on our human origin.

Mandibular ramus morphology and species identification in Australopithecus sediba

The site of Malapa, South Africa, has produced fossil evidence from multiple individuals of Australopithecus sediba including the partial skeletons designated as MH1 (holotype) and MH2 (paratype). A recent article in this Journal presented the hypothesis that MH1 and MH2 are not one species but instead represent two different genera: Australopithecus and Homo, respectively. Here we briefly evaluate this claim. We review the evidence from across the skeleton that demonstrates that MH1 and MH2 represent a single species, and we highlight other fossil samples that show the same pattern of mandibular ramus variation as observed in MH1 and MH2. The evidence shows that there is no reason to separate MH1 and MH2 into different species or genera based upon mandibular ramus morphology. This case illustrates how misleading small fragments of anatomy can be, why researchers should not use such fragments particularly for species and genus-level diagnoses, and why it is essential to use all available evidence. Significance:This study shows that the mandibular variation that is present in fossils from Malapa attributed to Australopithecus sediba has parallels in both Australopithecus africanus and in Homo. This helps to demonstrate that mandibular form is not sufficient to provide evidence of species diagnosis, but also that the development and adaptations to diet in Au. sediba were overlapping with those present in other related species of hominins.