The edge is already there: Experimental insights into the origins of stone tool technology

Research on the relationship between the evolution of ontogenetic locomotor milestones and the emergence of advanced cognition in early hominins is reviewed and discussed from an evo-devo perspective that incorporates theoretical underpinnings from the Extended Evolutionary Synthesis (EES). Comparative ontogenetic data from chimpanzee and human infants shed light on likely derivations in hominin locomotor milestones, their effect on the emergence of habitual bipedalism, and the latter's probable contribution(s) to cognitive evolution. Human babies' locomotor milestone of crawling on hands and knees is hypothesized to have been derived during hominin evolution in place of a knuckle-walking developmental stage that likely existed in the apelike predecessors of the earliest hominins. A review of comparative research suggests that evolutionary modifications in crawling, sitting, and pointing in addition to selection for bipedalism, contributed to the progressive evolution of both locomotion and advanced cognition in hominins. Comparisons of the ontogenetic development of locomotor stages in chimpanzee and human infants suggest that locomotor evolution and the emergence of advanced cognition were deeply intertwined during hominin evolution.

The lithic assemblage from the 700,000-year-old butchery site of Kalinga (Luzon Island, Philippines): New insights into technological variability in the Early Paleolithic in Island Southeast Asia.

The role of megafaunal exploitation in early human evolution remains debated. Occasional use of large carcasses by early hominins has been considered by some as opportunistic, possibly a fallback dietary strategy, and for others a more important survival strategy. At Olduvai Gorge, evidence for megafaunal butchery is scarce in the Oldowan of Bed I but becomes more frequent and widespread after 1.8 Ma in Bed II, coinciding with the emergence of Acheulean technologies, but not functionally related to the main Acheulian tool types. Here, we present the earliest direct evidence of proboscidean butchery, including a newly documented elephant butchery site (EAK). This shift in behavior is accompanied by larger, more complex occupation sites, signaling a profound ecological and technological transformation. Rather than opportunistic scavenging, these findings suggest a strategic adaptation to megafaunal resources, with implications for early human subsistence and social organization. The ability to systematically exploit large prey represents a unique evolutionary trajectory, with no direct modern analogue, since modern foragers do so only episodically.

The role of megafaunal exploitation in early human evolution remains debated. Occasional use of large carcasses by early hominins has been considered by some as opportunistic, possibly a fallback dietary strategy, and for others a more important survival strategy. At Olduvai Gorge, evidence for megafaunal butchery is scarce in the Oldowan of Bed I but becomes more frequent and widespread after 1.8 Ma in Bed II, coinciding with the emergence of Acheulean technologies, but not functionally related to the main Acheulian tool types. Here, we present the earliest direct evidence of proboscidean butchery, including a newly documented elephant butchery site (EAK). This shift in behavior is accompanied by larger, more complex occupation sites, signaling a profound ecological and technological transformation. Rather than opportunistic scavenging, these findings suggest a strategic adaptation to megafaunal resources, with implications for early human subsistence and social organization. The ability to systematically exploit large prey represents a unique evolutionary trajectory, with no direct modern analogue, since modern foragers do so only episodically.

The emergence of bipedal locomotion during human evolution has considerably reshaped the hominin pelvis, which also impacted the pelvic floor musculature. Among early hominins, australopithecines have an anteroposteriorly narrow, transversely wide bony pelvis. This study investigates whether this particular shape of the birth canal weakens the pelvic floor during childbirth in these hominins and if the pelvic floor contributes to rotational birth. As such, we explored the stress values at the pelvic floor that occur during the descent of the fetal head, using 3D models of extant humans based on the reconstruction of pelvic-fetal dyads from hospital records with known birth outcomes. We then compared this to 3D models based on pelvic reconstructions of A.L. 288-1 (Australopithecus afarensis), Sts 14 (A. africanus), and MH2 (A. sediba) using a 110 g neonatal brain weight. The early hominin pelvic floor was reconstructed by warping the pelvis and pelvic floor extracted from an MRI of a modern adult woman to the australopithecine pelvic morphology. Our results suggest that the range of stress values on the pelvic floor is comparable between humans (5.3-10.5 MPa) and australopithecines (4.9-10.7 MPa), suggesting that their females may have been exposed to a similarly high risk of perineal laceration during vaginal delivery as modern humans. None of the four australopithecine simulations, and only one out of two modern human simulations, showed an internal rotation of the fetal head into an occiput anterior orientation, suggesting this movement is particularly complex and involves influences beyond just the levator ani musculature.

Endurance pursuit hunting among recent foragers and its relevance for hominin locomotor evolution.

Some species of the Leucosphyrus Group of Anopheles mosquitoes in Southeast Asia are highly anthropophilic and efficient vectors of human malaria parasites, while others primarily feed on non-human primates (NHP) and transmit NHP malaria parasites. The evolutionary history of this group, particularly the origin of anthropophily, was studied using phylogenomic analysis of 2,657 high-confidence nuclear single-copy orthologous genes and 13 mitochondrial protein coding genes from 40 individuals of 11 species. Molecular dating and ancestral state reconstruction revealed that monkey-feeding is ancestral with speciation of monkey-feeding species dating to the Pliocene within Sundaland (Malay peninsula, Borneo, Sumatra and Java) which was covered in tropical rain forests during this period. Although less parsimonious alternatives cannot be excluded, molecular dating, ancestral state reconstruction and reticulation analysis indicated that anthropophily most likely evolved once, involving adaptive introgression, in the early Pleistocene in Sundaland, giving rise to multiple descendent anthropophilic species. Such early origination of anthropophily must necessarily have been in response to the arrival of early hominins (Homo erectus) rather than anatomically modern humans, likely associated with loss and fragmentation of rainforests during the early Pleistocene. The early origination of anthropophily also provides independent non-archaeological evidence supporting the limited fossil record of early hominin colonization in Southeast Asia around 1.8 Mya.

The ability of early hominins to adapt to diverse landscapes and ecological niches was a key factor in their range expansion. However, the behavioral and cognitive prerequisites underlying this adaptability remain poorly understood. Assuming that resource procurement played a pivotal role in hominin dispersal, we investigate the mobility-subsistence system of early Oldowan groups who occupied the Lower Omo landscape of southern Ethiopia some 2.3million years ago (Ma). With its extensive archaeological record and scattered lithic resources, this context provides a landscape-scale record of early hominin behavior. Multiple lines of evidence derived from an integrated environmental, spatial and technological analysis indicate a regionally-structured mobility strategy, involving the provisioning of quartz pebbles and the transport of partially transformed products from distant sources to the biotic-rich but stone-poor margins of the paleo-Omo River, where highly mobile foraging activities were concentrated along the meandering channel. This regional strategy of early hominin displacement reflects a "Shungura exception" in the Early Pleistocene record. It coincides with the emergence of stone tool-mediated activities in the Lower Omo Valley, marking a tipping point in the capacity of early hominins to develop environment-specific adaptive strategies‒a crucial asset for their expansion into new ecological niches.

Mandibular morphology in early hominins reflects both developmental processes and functional demands, yet the ontogenetic emergence of robust mandibular traits remains poorly understood. Here, we present cross-sectional analyses of cortical bone development during early mandibular ontogeny across Paranthropus robustus (N = 7), Paranthropus boisei (N = 1), Australopithecus africanus (N = 1), early Pleistocene Homo erectus (N = 1) and Homo habilis (N = 1), Pan troglodytes (N = 29), Pan paniscus (N = 34), and Homo sapiens (N = 24). We examined the cortical thickness and the structural properties at two key regions of the mandible-the symphysis and the corpus between the deciduous molars. We find that cortical bone thickness displays strong positive allometry with mandibular height across all taxa, with relative cortical thickness increasing significantly during early ontogeny. This pattern reflects normal ontogenetic bone growth, potentially reinforced by rising masticatory demands. In P. robustus, disproportionate cortical thickening and elevated resistance to bending-measured by the second moments of area-emerge early and become more pronounced throughout development. In contrast, the early Pleistocene Homo shows cortical thickening and second moments of area comparable to those of H. sapiens, even though H. habilis shares external morphological features with Paranthropus. Across all taxa, the mandibular robusticity index decreases during early ontogeny, reflecting proportionally greater increases in corpus height. However, this measure does not differentiate groups in infants and slightly older juveniles, whereas second moments of area reveal taxon-specific developmental patterns. These results highlight the value of second moments of area and, to a lesser extent, cortical thickening and robusticity index, for understanding ontogenetic and functional divergence among early hominins. They further suggest that robust morphology of Paranthropus stems from a distinct developmental trajectory established early in life.

Geochemical records from loess sediments provide insights into early hominin influence on the landscape in the Khovaling region of Southern Tajikistan, Central Asia

IntroductionThe accumulation of genomic and brain data opens new opportunities for resource friendly, data driven brain exploration. A key challenge is to develop versatile and accessible strategies that integrate and mine multimodal datasets for novel neuroscientific insights. Here, we optimized an integrated workflow for mapping multigenic evolutionary traits in the human brain across cognitive, cellular, and molecular levels.MethodsAt the input stage, the workflow fuses an evolutionary genetic dataset with searchable synthetic functional magnetic resonance imaging (fMRI) databases that are pre clustered into concise psychological domains for improved interpretability. At its core, a Genetic Algorithm for Generalized Biclustering (GABi) mines gene sets under evolutionary selection that also show high expression correlation with fMRI networks.ResultsApplying this workflow, we identified evolutionary patterns spanning cognitive traits, brain cell types, and molecular mechanisms. Focusing on socio affective traits, the algorithm highlighted peaks in adaptive selection in networks for social interaction (language) and social concepts (theory of mind) across hominid, early hominin, and anatomically modern human (AMH) ancestry. These traits emerge from a broad spectrum of excitatory (glutamatergic) and inhibitory (GABAergic) neuronal, as well as non neuronal, cell types. The associated Gene Ontology (GO) terms were enriched for cell signaling, synaptic organization, and neuronal morphology.DiscussionTogether, these findings demonstrate an integrated workflow for molecular to systems level exploration of the brain and provide new perspectives on the evolutionary history of human socio affective functions. This approach can be adapted to screen for functional traits in the context of mental disorders or applied to the brains of other phylogenies in a similar manner.

In hominins, the reduction of prognathism during craniofacial evolution was a significant derived trait differentiating Homo from earlier hominins and other apes and might have contributed significantly to calvarial expansion and encephalization. Gnathic remains of Australopithecus africanus, A. robustus, Homo habilis, and H. erectus from the Plio-Pleistocene boundary 5.3-2.6 MYA were studied for evidence of alveolar bone (AB) loss indicative of periodontal disease(s). AB loss may provide critical insights into craniofacial evolution and the divergence of Homo from the Australopithecines. AB loss in Plio-Pleistocene gnathic remains provides the fossilized hard evidence of the antiquity of periodontal diseases, the first recognized diseases in hominins' evolution. Seventy-one gnathic remains of Australopithecines and Homo species from Ditsong Museum of Natural History, Pretoria, and the School of Anatomy of the University of the Witwatersrand, Johannesburg, were examined using scanning electron microscopy (SEM) and macrophotography. Specimens were scanned at the microfocus X-ray tomography laboratory (MIXRAD) at Necsa, Pretoria, optimizing on highest spatial resolution and image contrast. Linear distances from the enamel-dentine junction (EDJ) to the remaining AB crest were also measured. Morphometric analyses showed that there is progressive AB loss as hominins speciated from Australopithecines to Homo. Homo remains showed statistically significant variation when analysing the linear distance between the EDJ and the remaining AB when compared with both Australopithecine taxa. AB loss was confirmed by microfocus X-ray tomography and, in Homo species only, showed a vertical pattern of bone loss with crateriform lesions and furcation defects. SEM and microfocus X-ray tomography, macrophotography, and linear measurements from the EDJ to the remaining alveolar bone showed that Homo had greater alveolar bone loss with intrabony defects and craters when compared with Australopithecines' taxa. There were no significant differences between the 2 Australopithecine species examined. The presented data show that Homo species developed significant AB loss. The data propose that random mutations of genes controlling odontometric values selected for a reduction of the size of the crowns during hominins' evolution. Smaller crowns ultimately resulted in weaker masticatory forces yet allowing masticatory function and thus survival in the presence of AB loss. Together with the speciation of smaller crowns, with reduction of masticatory muscle mass and thus masticatory forces, there was a reduction of prognathism leading to calvarial expansion with subsequent encephalization, speciating the Homo clade and later, the emergence of Homo sapiens.

Palaeogenetic evidence suggests that the last common ancestor of present-day humans, Neanderthals and Denisovans lived around 765–550 thousand years ago (ka)1. However, both the geographical distribution and the morphology of these ancestral humans remain uncertain. The Homo antecessor fossils from the TD6 layer of Gran Dolina at Atapuerca, Spain, dated between 950 ka and 770 ka (ref. 2), have been proposed as potential candidates for this ancestral population3. However, all securely dated Homo sapiens fossils before 90 ka were found either in Africa or at the gateway to Asia, strongly suggesting an African rather than a Eurasian origin of our species. Here we describe new hominin fossils from the Grotte à Hominidés at Thomas Quarry I (ThI-GH) in Casablanca, Morocco, dated to around 773 ka. These fossils are similar in age to H. antecessor, yet are morphologically distinct, displaying a combination of primitive traits and of derived features reminiscent of later H. sapiens and Eurasian archaic hominins. The ThI-GH hominins provide insights into African populations predating the earliest H. sapiens individuals discovered at Jebel Irhoud in Morocco4 and provide strong evidence for an African lineage ancestral to our species. These fossils offer clues about the last common ancestor shared with Neanderthals and Denisovans.

The Lower Paleolithic Late Acheulian marks an exceptional phase in human cultural evolution, encompassing notable transformations and innovations across Africa and Western Eurasia alongside the persistence of well-practiced Acheulian modes of adaptation. Lithic transformations mentioned here include innovative stone-working technologies such as prepared cores, Quina-like scrapers and possible origin of systematic blade production. These innovations provide a glance into potential changes in technological organization of lithic production that might reflect innovative modes of adaptation oriented towards changes in economy, environment and world-views of these early hominin groups. The open-air, Late Acheulian site of Jaljulia makes a significant contribution to the study of this transformative phase at the very end of the long Acheulian tradition in the Levant. The site was excavated to a relatively large extent (ca. 80m2) and the excavation yielded rich lithic assemblages of typical Late Acheulian technological components from several localities, dated to ca. 500–3/200 ka. The lithic assemblages are mostly dominated by flake-production, flake-tools, and numerous Handaxes. This paper presents the comprehensive analyses of the flint assemblages from five Jaljulia localities (Localities A–E). The results presented and discussed here are intriguing, as all five assemblages encompass components that could be regarded as forbearers of post-Acheulian industries. The use of prepared cores might signal an early appearance of the Middle Paleolithic Levallois concepts, and in order to stress this point, these cores are termed here “proto-Levallois”. Quina-like scrapers and blades are prominent, possibly reflecting the early adoption of technologies that became more common in the post-Acheulian, Acheuleo-Yabrudian cultural complex of the Levant. Based on this remarkable lithic repertoire, this paper discusses possible patterns of continuity and change in lithic production from the Late Acheulian to later industries and suggests refinements to the reduction trajectories variability.

Paleoanthropology could offer valuable insights into neurology by tracing the evolutionary origins of human motor and neural traits. Fossil evidence shows that bipedalism preceded brain expansion, revealing that upright locomotion and encephalization did not evolve in tandem. Early hominins retained ape-like brain organization despite walking upright, suggesting that neural complexity and prolonged childhood development emerged later. This sequence provides a framework for understanding persistent motor circuits in the human nervous system. Central pattern generators, deeply conserved networks producing rhythmic movements, exemplify ancestral continuities whose resilience explains the re-emergence of primitive motor patterns after cortical damage. Interpreting neurological signs through an evolutionary lens raises epistemological challenges, including the need for testable hypotheses and the avoidance of teleological bias. Yet clinically, reframing neurological signs, reflexes, and automatisms as evolutionary echoes could enrich diagnostic reasoning, inform prognosis, and inspire therapeutic strategies that harness ancestral circuits. In this sense, certain neurological signs may represent living traces of evolutionary history, bridging human ancestry with clinical practice.

The 1974 discovery of Lucy in Ethiopia marked a watershed moment in paleoanthropology. While the scientific community classifies Lucy as an extinct early hominin species that predates Homo sapiens by millions of years, in Ethiopia, she has been embraced as a national matriarch-the first human and mother of humanity. This commentary analyzes how government campaigns and media coverage actively promote a humanized, scientifically inaccurate identity for Lucy. By framing her as "one of us," these narratives sacrifice scientific facts for emotional resonance and commercial appeal. This popular mischaracterization creates significant obstacles for public science education and undermines scientific literacy, raising ethical questions about the role of the state and media in science communication. Ultimately, the article advocates for a balanced approach that celebrates Lucy's immense cultural and national importance without compromising the scientific integrity of human evolutionary science.

Out of Africa I revisited: Life history, energetics, and the evolutionary capacity for early hominin dispersals

The Sima del Elefante cave is one of the archaeopaleontological sites located in the karstic complex of Sierra de Atapuerca (Burgos, Spain), which is a remarkable locality for documenting an extensive sequence of human evidence. Within the stratigraphic sequence of the Sima del Elefante site, Level TE7 has yielded one of the oldest human remains recovered to date in western Europe. A hominin mid-face has recently been discovered (specimen ATE7-1), attributed to Homo aff. erectus. In this study, the fossil amphibian and reptile remains directly associated with this hominin are analyzed, described, and used to perform quantitative paleoecological reconstructions. The resulting herpetofaunal assemblage comprises a total of eight species: five anurans (Alytes gr. Alytes obstetricans/Alytes almogavarii, Pelodytes punctatus, Bufo gr. Bufo bufo, Epidalea calamita, and Rana temporaria), two lizards (small-sized Lacertidae indet. and Anguis fragilis), and two snakes (Coronella cf. Coronella austriaca and Vipera sp.). The paleoecological reconstruction was performed using the Mutual Ecogeographic Range method in conjunction with the Uncertain Distribution Area-Occupied Distribution Area technique to obtain temperature and precipitation estimates, and habitat weighting was used to infer the surrounding environment. The climate of TE7 was reconstructed as cool and humid, with an overall pattern concordant with a present-day continental Mediterranean climate, exhibiting similar temperatures and higher precipitation than today for the Sierra de Atapuerca location. The associated landscape evidenced a more humid environment, primarily made up of woodlands and open humid habitats with aquatic and periaquatic areas. The results obtained provide novel insights into the ecological tolerances of early hominins and thus contribute to the growing body of knowledge regarding their subsistence capabilities and behaviors.

Revisiting hominin scavenging through the lens of optimal foraging theory.