Early Homo Sapiens Research Articles

The species in paleoanthropology

The species is the basic unit of analysis in systematic paleontology. Yet, for most of its history the subfield of paleoanthropology has lacked any coherent concept of what fossil species are, using the species epithet variously at different times – most recently, with the conspicuous effect of minimizing apparent diversity among the hominins. The application of molecular systematic techniques to the analysis of high-latitude early Homo sapiens Linnaeus, 1758 and its contemporaries thus offers a welcome opportunity to reappraise our approaches to species recognition in the rapidly expanding hominin fossil record. But it must be cautioned that evidence for hybridization among documented or hypothesized lineages cannot necessarily be taken as evidence for recoalescence among them, and that “braided stream” models of hominin evolution (which militate against speciation) cannot ­account for the diversity of historically and morphologically differentiated entities we see in that record.

Craniometric variation and the ancestry of modern humans.

Ancient and contemporary DNA provide information about geographic variation in the ancestry of present-day humans. All living populations have ancestry from early Homo sapiens originating in sub-Saharan Africa. Populations of Eurasian descent also have a small amount of Neandertal ancestry. This study examines whether craniometric distances between recent modern human samples reflect this geographic variation in ancestry. Among recent modern humans, Eurasians are expected to be more similar to Neandertals, whereas both sub-Saharan Africans and Eurasians are expected to be equidistant from early H. sapiens. Data on 33 craniometric traits from 2524 recent modern humans were compared with data from the literature for Neandertals and early H. sapiens. Mahalanobis distances were computed for each modern specimen to both the Neandertal and early H. sapiens means. These distances were examined for differences between recent humans from sub-Saharan Africa (N = 373) and those of Eurasian descent (N = 2151). Eurasians as a group are significantly closer than sub-Saharan Africans to Neandertals. There is no significant difference between the distances of sub-Saharan Africans and Eurasians to early H. sapiens. The differences between sub-Saharan Africans and Eurasians for both Neandertals and early H. sapiens are as expected. Although there has been geographic differentiation among recent modern humans, including differences in Neandertal admixture, these differences have not affected overall similarity of recent modern sub-Saharan Africans and Eurasians to the earliest samples of H. sapiens.

Chronometric data and stratigraphic evidence support discontinuity between Neanderthals and early Homo sapiens in the Italian Peninsula

The process by which Palaeolithic Europe was transformed from a Neanderthal-dominated region to one occupied exclusively by Homo sapiens has proven challenging to diagnose. A blurred chronology has made it difficult to determine when Neanderthals disappeared and whether modern humans overlapped with them. Italy is a crucial region because here we can identify not only Late Mousterian industries, assumed to be associated with Neanderthals, but also early Upper Palaeolithic industries linked with the appearance of early H. sapiens, such as the Uluzzian and the Aurignacian. Here, we present a chronometric dataset of 105 new determinations (74 radiocarbon and 31 luminescence ages) from four key southern Italian sites: Cavallo, Castelcivita, Cala, and Oscurusciuto. We built Bayesian-based chronometric models incorporating these results alongside the relative stratigraphic sequences at each site. The results suggest; 1) that the disappearance of Neanderthals probably pre-dated the appearance of early modern humans in the region and; 2) that there was a partial overlap in the chronology of the Uluzzian and Protoaurignacian, suggesting that these industries may have been produced by different human groups in Europe.

Seasonal landscape variability advances Lantian hominin's recognition capacity to strategically adapt to changing environments

Environmental Variability Selection (EVS) is hypothesized for the emergence of early Homo (H.) sapiens with small lithic tools in Africa. Yet, it is unclear how the EVS works when a special hominin group with advanced small lithic tools evolved from the Asian H. erectus with expedient core and flake industry. Lantian loessland in southern Chinese Loess Plateau in North China preserves continuous and concentrated hominin fossil, faunal, pollen, stone tool, paleoclimate, and landform records for last 2 million years (Ma) and is an ideal place to test this hypothesis. We reanalyzed δ13C values of soil organic and inorganic carbon from 2 Lantian loess-paleosol records to partition seasonal climate and habitat changes with synthesized lithic, faunal, and pollen data to seek cluses. We found that Lantian Gongwangling and Chenjiawo H. erectus adapts to woodland-forest habitats, manufacturing Mode 1 stone artifacts foraging subtropical animals in warm and Paleoarctic animals in cool seasons on the low and medium-high rolling loessland, while more advanced Dali hominins adapt to certain steppe-shrubland habitats manufacturing diverse small-sized lithic tools to forage more open-habitat animals in all seasons on hilly landforms. We propose that co-evolution of seasonal habitat variability and changing local landforms in 2.0–0.2 Ma advances Dali hominin's cognitive capacity for strategically using landform morphology for subsistence and manufacture small stone tools for intercepting high fluxes of seasonal resources on highly variable loessland. Seasonal landscape variability and landform evolution is the key in the EVS for the evolution from Asian H. erectus to a more advanced hominin group or species.

Abrupt onset of intensive human occupation 44,000 years ago on the threshold of Sahul

Archaeological evidence attests multiple early dispersals of Homo sapiens out of Africa, but genetic evidence points to the primacy of a single dispersal 70-40 ka. Laili in Timor-Leste is on the southern dispersal route between Eurasia and Australasia and has the earliest record of human occupation in the eastern Wallacean archipelago. New evidence from the site shows that, unusually in the region, sediment accumulated in the shelter without human occupation, in the window 59–54 ka. This was followed by an abrupt onset of intensive human habitation beginning ~44 ka. The initial occupation is distinctive from overlying layers in the aquatic focus of faunal exploitation, while it has similarities in material culture to other early Homo sapiens sites in Wallacea. We suggest that the intensive early occupation at Laili represents a colonisation phase, which may have overwhelmed previous human dispersals in this part of the world.

Unravelling human migrations: DISPERSALS Project sheds light on early Homo sapiens' journey

Unravelling human migrations: DISPERSALS Project sheds light on early Homo sapiens' journey DISPERSALS will compare the human occupation and ecology between central Mozambique and eastern and southern Africa using a multi-scale approach based on the study of regional diachronic cultural traits. It will reconstruct regional population patterns, followed by comparative quantitative population genetics combined with GIS computational network analyses. The results will then be integrated through agent-based modelling, based on the incremental creation, elimination, or reorientation of network links to simulate a quantitative framework to study the evolution of population dispersal across southern-eastern Africa. The project will be crucial in providing groundbreaking high-resolution archaeological, chronological and paleoenvironmental data. DISPERSALS will deliver a fundamental perspective on the key processes that triggered migrations and dispersals within Africa and out of Africa, ultimately resulting in the human diaspora over the entire planet.

Finite element analysis of Neanderthal and early Homo sapiens maxillary central incisor

Neanderthal anterior teeth are very large and have a distinctive morphology characterized by robust ‘shovel-shaped’ crowns. These features are frequently seen as adaptive responses in dissipating heavy mechanical loads resulting from masticatory and non-masticatory activities. Although the long-standing debate surrounding this hypothesis has played a central role in paleoanthropology, is still unclear if Neanderthal anterior teeth can resist high mechanical loads or not. A novel way to answer this question is to use a multidisciplinary approach that considers together tooth architecture, dental wear and jaw movements. The aim of this study is to functionally reposition the teeth of Le Moustier 1 (a Neanderthal adolescent) and Qafzeh 9 (an early Homo sapiens adolescent) derived from wear facet mapping, occlusal fingerprint analysis and physical dental restoration methods. The restored dental arches are then used to perform finite element analysis on the left central maxillary incisor during edge-to-edge occlusion. The results show stress distribution differences between Le Moustier 1 and Qafzeh 9, with the former displaying higher tensile stress in enamel around the lingual fossa but lower concentration of stress in the lingual aspect of the root surface. These results seem to suggest that the presence of labial convexity, lingual tubercle and of a large root surface in Le Moustier 1 incisor helps in dissipating mechanical stress. The absence of these dental features in Qafzeh 9 is compensated by the presence of a thicker enamel, which helps in reducing the stress in the tooth crown.

Did climate change make Homo sapiens innovative, and if yes, how? Debated perspectives on the African Pleistocene record

Our enhanced capacity to innovate is a key feature that sets Homo sapiens apart as a species. The Middle Stone Age archaeological record of Pleistocene Africa documents the emergence and elaboration of this capacity, and its relationship to changes in past climate and environments. However, the models and interpretations developed to understand the relationship between early Homo sapiens’ innovativeness and climate change are varied and often contradictory. Here, we review these contrasting interpretations. We contend that while climate change may have influenced early human innovation, it was in an inconsistent and multifaceted way.

Ecology and demography of early Homo sapiens: a synthesis of archaeological and climatic data from eastern Africa

ABSTRACT Eastern Africa maintains a key position in debates surrounding the emergence of Homo sapiens across Africa. Extensive research in the region has revealed a rich fossil record in association with a ‘generic’ but variable Middle Stone Age (MSA) material culture, providing an important laboratory for testing hypotheses about the behavioural evolution of our species. For example, multiple archaeological studies of the eastern African MSA note a link between the distribution and density of sites, archaeological diversity and environmental conditions, with ecology and demography often cited as key drivers of cultural evolution. This article formulates new hypotheses using theoretical models of complex fitness landscapes of evolution and reviews the archaeological and climatic records of Middle-late Pleistocene eastern Africa in the light of these ideas. It proposes that evidence from eastern Africa implicates much of the region as a refugial zone within Pleistocene Africa, providing consistently suitable conditions for survival that were characterised by high and changing biodiversity, facilitating population growth and interconnectivity as well as material culture diversification. Interactions between different evolutionary processes likely resulted in the complex cultural mosaic observed across Africa, including the appearance of ‘specific’ innovations against a backdrop of more ‘generic’ MSA elements.

The generic Middle Stone Age: fact or fiction?

ABSTRACT Recent decades have seen a surge of interest in the Middle Stone Age (MSA) as it constitutes the archaeological background to the early evolution of Homo sapiens. Research primacy has been given to rare regional and temporal signatures of MSA technological diversity and material culture, typically in open grassland or sparse savanna regions. These include, for example, the Still Bay, Howiesons Poort, Lupemban and Aterian, all of which can be seen as specific variants of the MSA. Archaeological assemblages apparently lacking distinctive features have received little attention in their own right. Such occurrences can be subsumed under the informal term of a more ‘generic’ MSA. The marginalisation of this material culture is problematic as it dominates the MSA record. The apparent continuity and commonality of generic MSA elements over large spatial and temporal scales also raise manifold questions about the early evolution of our species. As such, a ‘generic’ MSA might be perceived as the common technological and material substrate of early Homo sapiens behaviour and culture. At the same time, we lack quantitative studies that justify subsuming close to 300,000 years of material culture into a single category. This special issue of Azania is based on a symposium at the Sixteenth Congress of the PanAfrican Archaeological Association of Prehistory and Related Studies in Zanzibar (Tanzania) that brought together researchers working in different African regions to scrutinise apparently ‘non-specific’ MSA lithic assemblages across time and space, evaluating their commonality and relevance on different chronological and geographical scales. The six articles in this issue span comparative quantitative studies within and across regions, methodological and theoretical advances to reach these goals and the integration of palaeoecological data. A common interest lies in understanding but also testing the validity of using a ‘generic’ MSA and the general relevance of more specific or generic technological assemblages in the wider framework of modern human cultural and biological evolution.

Language likely promoted peace before 100,000 ya.

Based on evidence of selection against alpha-male behavior in the earliest Homo sapiens, I suggest that by 300,000 ya (years ago) language would have been sufficiently sophisticated to contribute to peacemaking between groups. Language also influenced the social landscape of peace and war, and groups' ability to form coalitions.

The Middle Stone Age of Atlantic Africa: A critical review

Evidence of early Homo sapiens populations at the Atlantic coast of Africa remains relatively poorly known in relation to other regions of the continent. Nevertheless, available data across the continent provides a good starting point for current and future research investigations. The many sites known, documented and studied contribute in an increasingly way to the global understanding of the human emergence, including evidence of human evolutionary and technological advances, specific adaptations to diverse environments, the diffusion of Homo species and how humans interacted with each other from the “Early Stone Age (ESA)” through to the Middle Stone Age (MSA) from northern and southern Africa to the West. The differences of knowledge between the Atlantic coast in regard to other regions might be attributed to a number of reasons including but not limited to the history of scientific interest, site formation processes or economic, institutional and political constraints. However, the region received a renewed attention and funds that, combined with new methods and techniques, has been allowing an increased training of new researchers and the acquisition of high-resolution archaeological, paleoenvironmental and chronological data. Together, these inputs will reduce the differences of knowledge between the Atlantic coast and the Northern, Southern and Eastern Africa regions. The African Atlantic Coast represents more than 40% of the continent's perimeter, covering all Africa's climate zones, the hot arid environments, mountainous regions, and tropical rainforest could become relevant barriers for human mobility, but the shallow continental platform, and the great number of river basins allowed mobility between north and south coastal biomes into the continental interiors. These may have provided predictable patchy clusters of resources allowing human populations to thrive, enabling greater mobility and consequent diffusion of cultural traits, resources, and DNA. In this paper we review the record about the prehistory, paleoenvironments and paleoanthropological visibility and potentiality of Atlantic Africa.

Palaeoenvironments and hominin evolutionary dynamics in southeast Asia

Secure environmental contexts are crucial for hominin interpretation and comparison. The discovery of a Denisovan individual and associated fauna at Tam Ngu Hao 2 (Cobra) Cave, Laos, dating back to 164–131 ka, allows for environmental comparisons between this (sub)tropical site and the Palearctic Denisovan sites of Denisova Cave (Russia) and Baishiya Karst Cave (China). Denisovans from northern latitudes foraged in a mix of forested and open landscapes, including tundra and steppe. Using stable isotope values from the Cobra Cave assemblage, we demonstrate that, despite the presence of nearby canopy forests, the Denisovan individual from Cobra Cave primarily consumed plants and/or animals from open forests and savannah. Using faunal evidence and proxy indicators of climates, results herein highlight a local expansion of rainforest at ~ 130 ka, raising questions about how Denisovans responded to this local climate change. Comparing the diet and habitat of the archaic hominin from Cobra Cave with those of early Homo sapiens from Tam Pà Ling Cave (46–43 ka), Laos, it appears that only our species was able to exploit rainforest resources.

The stratigraphy and formation of Middle Stone Age deposits in Cave 1B, Klasies River Main site, South Africa, with implications for the context, age, and cultural association of the KRM 41815/SAM-AP 6222 human mandible

Cave 1B, in the Klasies River Main site complex (KRM), is best known for the recovery of the KRM 41815/SAM-AP 6222 human mandible. After initial skepticism over the modernity of this specimen, it is accepted that the mix of archaic and modern traits it displays is characteristic of early Homo sapiens individuals. Different authors have associated this specimen with the Middle Stone Age (MSA) I and II/Mossel Bay cultural phases, but the published data do not allow an unambiguous attribution. KRM 41815's frequent use in studies of the evolution of the human mandible, and its well-developed chin, makes clarifying its age and context important objectives. The field and micromorphology observations presented here provide greater insight into the stratigraphy and formation of the sequence exposed in the PP38 excavation. There are three major divisions: the basal Light Brown Sand (LBS) Member (not excavated), the Rubble Sand (RS) Member (MSA I), and the Shell and Sand Dark Carbonized (SASDC) Submember (MSA II). Cultural stratigraphy based on lithic artifacts remains the only way to make secure (but broad) temporal correlations with the rest of the site complex. This investigation shows that a range of anthropogenic, geogenic, and biogenic processes contributed to the deposition and post-depositional alteration of the identified microfacies. Short depositional hiatuses are reasonably common, and a significant hiatus was identified between the RS and SASDC. The impact of post-depositional processes on the RS is significant, with anthropogenic deposits poorly preserved. In comparison, the SASDC is dominated by hearths contained within deposits rich in reworked anthropogenic materials known as carbonized partings. Small shell disposal features are also present. The distribution of these anthropogenic features suggests continuity in the management of space throughout the MSA II occupations, from before 110 ka. New stratigraphic correlations indicate that KRM 41815 is unambiguously associated with the MSA I. Therefore, it predates 110 ka, with a lower age limit potentially in Marine Isotope Stage 6.

Preliminary study of two deciduous human molars from the Late Pleistocene layers of Song Terus (East Java): A window into the last Homo erectus and the first Homo sapiens in Java

Java is one of the oldest places outside Africa which was occupied by early humans, from the first ‘archaic’ Homo erectus after 1.8ma to the progressive form around 70-40ka. Up to now, paleoanthropologists do not know clearly when the anatomically modern human started to colonize this island. Some previous scholars proposed scenarios which presumed to be as early as 125ka, or just after one of the Toba eruptions after 74ka, and or at least to the last glacial maximum about 21ka. This research tried to contribute to the question about the history of human occupation in Java during the Late Pleistocene. Two unpublished deciduous teeth discovered in the Song Terus site are considered: ST06 is dated back from older than 80ka and another tooth ST04 is younger than 60ka. We compared both specimens with Homo erectus s.l., Neanderthal, ancient and recent Homo sapiens, to identify their taxonomical position. Morphological and metrical comparative analysis of the external and internal dental characters were observed. Preliminary results show that ST04 is closed to Homo sapiens while ST06 belongs to the Homo erectus s.l. group. It confirms that Homo erectus was still survived at least at the beginning of the Late Pleistocene, during the last interglacial maximum period (125ka). Moreover, it suggested that Homo sapiens was probably present in Java Island after 60ka at the same time as a renewal of the local fauna takes place. It could imply a chronological succession of occupations between the last Homo erectus and early Homo sapiens in Southeast Asia.

Language evolution and computational capabilities: conceptualization of the first language units

This work addresses from the perspective of evolutionary pressure, the delicate issue of the mechanisms and causes that are behind the emergence of the faculty of language among early Homo sapiens ancestors. It mainly focuses on the motives or driving forces that are behind the emergence of the first units of language. The latter are defined in this paper, as the first vocal signals that convey information and meanings that go far beyond the usual vocal repertoire of non-human primates. They emerged as a consequence to make a sense to the principle of fairness by probing equal amounts of quantities in the context of food sharing operations after a collaborative labor. Early hominins realized that learning how to make equal food quantities, which should be regarded today as the most fundamental level for doing mathematics, is a prerequisite for the sustainability of collaborative labor (cooperation). This ancestral computing innovation is shown in this paper to be the greatest achievement of evolution in the Homo lineage. By developing the first computational capabilities, early hominins passed successfully the transition that allowed them to move from the instinct driven behavior, which prevails in the animal realm, to reasoning guided behavior in which processing information and language are two fundamental consequences.

Fluvial response to Quaternary hydroclimate in eastern Africa: Evidence from Gona, Afar, Ethiopia

The Busidima Formation in the Afar region, Ethiopia, spans the Quaternary and records the cultural evolution of the genus Homo. Yet, the Middle Pleistocene to Holocene fluvial environments in which early humans lived are undersampled in eastern Africa. This paper examines the stratigraphy, geochronology and paleoenvironments of the newly designated Odele Member of the uppermost Busidima Formation (<152 thousand years ago (ka)), which has received little attention despite representing a critical period in the evolution of early Homo sapiens and its migration out of Africa. The Odele Member is 40–50 m thick and is dated using tephrochronology, radiometric, luminescence, and electron spin resonance techniques. The member spans 151 to 7 ka, defined at the base by the widespread Waidedo Vitric Tuff (WAVT, 151 ± 16 ka modeled age and 95.4% credible interval - C.I.). There are two prominent erosional unconformities in the Odele Member, a lower one after the WAVT deposition with a modeled 95.4% C.I. range of 124–97 ka; and an upper one involving widespread alluvial fan incision commencing between 21.7 and 12.9 ka. The uppermost Odele Member also contains black, organic-rich mats, redox features, reed casts, and freshwater gastropods marking wetter conditions during the terminal Pleistocene and Early Holocene. A black, fine-grained relict soil coeval with the Halalalee paleosol bounds the top of the Odele Member and has mollic and vertic properties, weathering since ∼12 ka. These incision events and prominent paleosol development near/at the top of the Busidima Formation document Middle to Late Pleistocene Awash River incision to its present-day course. Paleo-rainfall estimates suggest that the Early Holocene-age Halalalee paleosol weathered under a climate with mean annual rainfall 10–15% higher than today. A compilation of radiocarbon ages from aquatic gastropods, carbonized wood and charcoal from the upper Odele Member shows wetter and possibly more vegetated conditions during late marine isotope stage (MIS) 3 and the African Humid Period (AHP) that are tightly coupled with precession-driven summer insolation maxima. These key findings suggest that periods of incision, aggregation, and landscape stability in the Odele Member have an orbital precession pacing. The Odele Member revises upward the age of the Busidima Formation to 7 ka, showing that it spans into the Holocene and now includes Middle and Later Stone Age archaeological traditions.

Revisiting the age of the Florisbad hominin material

In 1996, Grün and coworkers provided an ESR age determination for a hominin molar from Florisbad, South Africa, at 259 ± 35 ka. The most anatomically informative hominin specimen from Florisbad is a fragmentary craniofacial specimen, attributed by many to early Homo sapiens, which has been assumed to derive from the same individual as this tooth. Since 1996, evidence about the evolutionary context for the later Middle Pleistocene and its associated hominins in Africa had markedly changed. If the Florisbad date is accurate and if the molar is associated with the craniofacial specimen, this evidence may suggest that Homo naledi coexisted in time and geography with H. sapiens in southern Africa. Thus, the accuracy for all dates needs critical investigation. This study examines the published record of excavation and subsequent analyses for the Florisbad material. We find that the contemporary records raise doubt about the contemporaneity of the tooth and calvaria. The site's complex stratigraphy and the details about the tooth's discovery also pose challenges for the previous ESR age estimate. Because the fragmentary cranial specimen has value for morphological comparisons, developing additional means of understanding its geological age is necessary. The current data do not demonstrate the presence of H. sapiens in southern Africa at ~260 ka.

Evidence for large land snail cooking and consumption at Border Cave c. 170–70 ka ago. Implications for the evolution of human diet and social behaviour

Fragments of land snail (Achatinidae) shell were found at Border Cave in varying proportions in all archaeological members, with the exception of the oldest members 5 WA and 6 BS (>227,000 years ago). They were recovered in relatively high frequencies in Members 4 WA, 4 BS, 1 RGBS and 3 WA. The shell fragments present a range of colours from lustrous beige to brown and matt grey. The colour variability can occur when shell is heated. This possibility was explored here through experimental heating of giant land snail shell fragments (Achatinidae, Metachatina kraussi - brown lipped agate snail) in a muffle furnace from 200 to 550 °C for different lengths of time. Colour change, weight loss, and shattering of the heated samples were recorded. Transformation of aragonite into calcite and the occurrence of organic material was investigated by means of Infrared and Raman spectroscopy. Scanning electron microscopy was also used on selected specimens to help identify heat-induced transformation as opposed to taphonomic alteration. The identification on archaeological fragments of features produced by experimentally heating shells at high temperatures or for long periods has led us, after discarding alternative hypotheses, to conclude that large African land snails were systematically brought to the site by humans, roasted and consumed, starting from 170,000 years ago and, more intensively between 160,000 and 70,000 years ago. Border Cave is at present the earliest known site at which this subsistence strategy is recorded. Previous research has shown that charred whole rhizomes and fragments of edible Hypoxis angustifolia were also brought to Border Cave to be roasted and shared at the site. Thus, evidence from both the rhizomes and snails in Border Cave supports an interpretation of members of the group provisioning others at a home base, which gives us a glimpse into the complex social life of early Homo sapiens.

Hypercementosis in Late Pleistocene Homo sapiens fossils from Klasies River Main Site, South Africa

ObjectiveTo examine early Homo sapiens fossils from the Late Pleistocene site of Klasies River Main Site, South Africa for evidence of hypercementosis. The specimens represent seven adult individuals dated to between 119,000 and 58,000 years ago. These observations are contextualized in relation to the incidences of hypercementosis among recent human populations and fossil human samples and the potential etiologies of hypercementosis. DesignThe fossils were investigated utilizing micro-CT and nano-CT scanning to visualize and measure cementum apposition on permanent incisor, premolar and molar roots. Cementum thickness was measured at mid-root level, and the volume of the cementum sleeve was calculated for the two fossil specimens that display marked hypercementosis. ResultsTwo of the fossils display no evidence of cementum hypertrophy. Three exhibit moderate cementum thickening, barely attaining the quantitative threshold for hypercementosis. Two evince marked hypercementosis. One of the Klasies specimens with marked hypercementosis is judged to be an older individual with periapical abscessing. The second specimen is a younger adult, and seemingly similar in age to other Klasies fossils that exhibit only minimal cementum apposition. However, this second specimen exhibits dento-alveolar ankylosis of the premolar and molars. ConclusionsThese two fossils from Klasies River Main Site provide the earliest manifestation of hypercementosis in Homo sapiens.