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The discovery of the Taung Child was a significant milestone that not only challenged the then-prevailing belief in humanity's Eurasian origins but also inspired a new wave of palaeontological research across the African continent, particularly in eastern Africa. This discovery provided compelling evidence supporting Darwin's theory of an African ancestor for all hominins. The impact of this discovery can be seen in the surge of palaeontological surveys in eastern Africa, which have, over the years, yielded a wealth of fossilised fauna remains, including outstanding hominin fossils from the eastern African sites.

The site of Malapa, South Africa, has produced fossil evidence from multiple individuals of Australopithecus sediba including the par tial skeletons designated as MH1 (holotype) and MH2 (paratype). A recent ar ticle 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 par ticularly for species and genus-level diagnoses, and why it is essential to use all available evidence. 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. The MH1 and MH2 skeletons are among the most complete known for Australopithecus, dating to approximately 1.977 million years ago.1,2 The preserved elements of each skeleton include portions of upper and lower limb, thorax, pelvis, mandible, dentition and, for MH1, the face and cranial vault.1,3 These remains are among the most studied of any early hominin specimens. Excavation at Malapa has recovered substantial evidence of the burial position of each skeleton, including joints found in articulation or in close anatomical proximity, with all recovered parts showing a low degree of post-mortem dispersion.4 Additional context comes from the different ontogenetic stages and biological sex of the two skeletons. MH2 is adult and MH1 is juvenile with postcranial and dental elements consistent with a maturational age of between 9 and 11 years when compared to a chimpanzee maturational pattern.5 The pelvic remains of MH1 and MH2 are closely similar in size, and similar in most aspects of morphology, but differ in features related to sex, suggesting female sex for MH2 and male sex for MH1.6,7 The slightly larger size of MH1 in many dental and postcranial measurements is consistent with this sex difference. The metric differences between MH1 and MH2 are consistently slight in comparison to the variation observed within other hominin fossil samples that represent single species, within living humans, and within species of other living great apes. The mandibles of both skeletons preserve most of their mandibular dentition, and the teeth of both individuals are very similar in size and morphology.Significance: This study shows that the mandibular variation that is present in fossils from Malapa attributed to Australopithecussediba 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.

The evolution of the human pattern of axial segmentation has been the focus of considerable discussion in paleoanthropology. Although several complete lumbar vertebral columns are known for early hominins, to date, no complete cervical or thoracic series has been recovered. Several partial skeletons have revealed that the thoracolumbar transition in early hominins differed from that of most extant apes and humans. Australopithecus africanus, Australopithecus sediba, and Homo erectus all had zygapophyseal facets that shift from thoracic-like to lumbar-like at the penultimate rib-bearing level, rather than the ultimate rib-bearing level, as in most humans and extant African apes. What has not been clear is whether Australopithecus had 12 thoracic vertebrae as in most humans, or 13 as in most African apes, and where the position of the thoracolumbar transitional element was. The discovery, preparation, and synchrotron scanning of the Australopithecus afarensis partial skeleton DIK-1-1, from Dikika, Ethiopia, provides the only known complete hominin cervical and thoracic vertebral column before 60,000 years ago. DIK-1-1 is the only known Australopithecus skeleton to preserve all seven cervical vertebrae and provides evidence for 12 thoracic vertebrae with a transition in facet morphology at the 11th thoracic level. The location of this transition, one segment cranial to the ultimate rib-bearing vertebra, also occurs in all other early hominins and is higher than in most humans or extant apes. At 3.3 million years ago, the DIK-1-1 skeleton is the earliest example of this distinctive and unusual pattern of axial segmentation.

We describe late Pliocene and early Pleistocene hominin fossils from Sterkfontein Caves (South Africa), including two femoral specimens, as well as a partial tibia and a partial fibula. The fossils are likely assignable to Australopithecus africanus and/or Australopithecus prometheus and the morphology of each corroborates previous interpretations of Sterkfontein hominins as at least facultative bipeds.Significance: • A recent series of papers by our research team describes the morphology of a hominin skeleton from Sterkfontein Caves (South Africa), nicknamed ‘Little Foot’. Based on its unique skull morphology, R.J. Clarke, the skeleton’s discoverer, places it in the species Australopithecus prometheus, as distinct from the better-known and co-occurring Australopithecus africanus. Here we describe additional hominin thigh and leg fossils from Sterkfontein that, when considered in a comparative context, support the hypothesis that there was significant (probably interspecific) variation in South African hominin postcranial morphology during the late Pliocene and early Pleistocene.

Many researchers have suggested that Australopithecus anamensis and Australopithecus afarensis were among the earliest hominins to have diets that included hard, brittle items. Here we examine dental microwear textures of these hominins for evidence of this. The molars of three Au. anamensis and 19 Au. afarensis specimens examined preserve unobscured antemortem microwear. Microwear textures of these individuals closely resemble those of Paranthropus boisei, having lower complexity values than Australopithecus africanus and especially Paranthropus robustus. The microwear texture complexity values for Au. anamensis and Au. afarensis are similar to those of the grass-eating Theropithecus gelada and folivorous Alouatta palliata and Trachypithecus cristatus. This implies that these Au. anamensis and Au. afarensis individuals did not have diets dominated by hard, brittle foods shortly before their deaths. On the other hand, microwear texture anisotropy values for these taxa are lower on average than those of Theropithecus, Alouatta or Trachypithecus. This suggests that the fossil taxa did not have diets dominated by tough foods either, or if they did that directions of tooth–tooth movement were less constrained than in higher cusped and sharper crested extant primate grass eaters and folivores.

The cranial morphology of the earliest known hominins in the genus Australopithecus remains unclear. The oldest species in this genus ( Australopithecus anamensis , specimens of which have been dated to 4.2–3.9 million years ago) is known primarily from jaws and teeth, whereas younger species (dated to 3.5–2.0 million years ago) are typically represented by multiple skulls. Here we describe a nearly complete hominin cranium from Woranso-Mille (Ethiopia) that we date to 3.8 million years ago. We assign this cranium to A. anamensis on the basis of the taxonomically and phylogenetically informative morphology of the canine, maxilla and temporal bone. This specimen thus provides the first glimpse of the entire craniofacial morphology of the earliest known members of the genus Australopithecus . We further demonstrate that A. anamensis and Australopithecus afarensis differ more than previously recognized and that these two species overlapped for at least 100,000 years—contradicting the widely accepted hypothesis of anagenesis. Two related studies describe a newly discovered cranium of Australopithecus anamensis , the environment in which this hominin would have lived approximately 3.8 million years ago and how it is related to Australopithecus afarensis .

While there is broad agreement that early hominins practiced some form of terrestrial bipedality, there is also evidence that arboreal behavior remained a part of the locomotor repertoire in some taxa, and that bipedal locomotion may not have been identical to that of modern humans. It has been difficult to evaluate such evidence, however, because of the possibility that early hominins retained primitive traits (such as relatively long upper limbs) of little contemporaneous adaptive significance. Here we examine bone structural properties of the femur and humerus in the Australopithecus afarensis A.L. 288-1 (\"Lucy\", 3.2 Myr) that are known to be developmentally plastic, and compare them with other early hominins, modern humans, and modern chimpanzees. Cross-sectional images were obtained from micro-CT scans of the original specimens and used to derive section properties of the diaphyses, as well as superior and inferior cortical thicknesses of the femoral neck. A.L. 288-1 shows femoral/humeral diaphyseal strength proportions that are intermediate between those of modern humans and chimpanzees, indicating more mechanical loading of the forelimb than in modern humans, and by implication, a significant arboreal locomotor component. Several features of the proximal femur in A.L. 288-1 and other australopiths, including relative femoral head size, distribution of cortical bone in the femoral neck, and cross-sectional shape of the proximal shaft, support the inference of a bipedal gait pattern that differed slightly from that of modern humans, involving more lateral deviation of the body center of mass over the support limb, which would have entailed increased cost of terrestrial locomotion. There is also evidence consistent with increased muscular strength among australopiths in both the forelimb and hind limb, possibly reflecting metabolic trade-offs between muscle and brain development during hominin evolution. Together these findings imply significant differences in both locomotor behavior and ecology between australopiths and later Homo.

South Africa is host to the single richest early hominin fossil record worldwide, including many examples of the endemic species Australopithecus africanus fossils. This species was first described by Raymond Dart in 1925 from the deposits near the town of Taung. Later, many more fossils, of different species and genera, were found in the caves of the Sterkfontein and Makapan Valleys. To understand this rich and diverse fossil record, we must understand how the landscape formed (cave formation processes) and changed (mining), when this happened (geochronology), and how the fossils were accumulated and modified (taphonomy). Here we provide a review of these themes to mark the centenary of the Taung Child discovery. We mark this moment in our field by critically reflecting on the role of extractive practices, especially centred around past mining of the Caves and the exclusion of many members of research teams. The South African Fossil Hominid sites provide a unique opportunity to expand our understanding of the intersection between human evolution and changing environmental conditions, as the karstic landscape and remnant cave systems preserve both fossils and sedimentary archives of past environmental change. We offer a perspective on future research areas: more standardised excavation practices and techniques to raise the quality of data collected from the caves and new techniques to date and extract palaeoclimate data from cave deposits themselves, to provide novel insights into the world of the early australopiths.

In 1925, Raymond Ar thur Dar t published his description and interpretations of the 'Taung Child' in the journal Nature, including a description of the natural brain endocast associated with the face and mandible. Details preserved in the endocast of the Taung Child have opened critical questions and debates about how the human brain evolved, and how to identify and study evidence of brain changes from fossil hominin crania. In this paper, we review and synthesise methodological innovations (how do we study fossil hominin brains?) and critical conceptual shifts (how did the hominin brain evolve?) triggered by the discovery of the Taung Child. In par ticular, we detail the impact of the study of the well-preserved crania and natural endocasts from the southern African hominin-bearing sites on our understanding of brain evolution and the integration of newly developed analytical tools into research in palaeoneurology (e.g. imaging techniques, 3D modelling). Additionally, we examine how the use of digital replicas of fossil hominin endocasts and the need to study extant human brains to form a comparative platform might raise questions about research practices (e.g. study and exhibition of fossil and extant human brains) and management of such invaluable heritage resources (e.g. data sharing). We finally consider how our view of human brain evolution, and in par ticular the putative uniqueness of the hominin brain, has changed over the last century.

The earliest evidence of Australopithecus goes back to ca 4.2 Ma with the first recorded appearance of Australopithecus ‘anamensis’ at Kanapoi, Kenya. Australopithecus afarensis is well documented between 3.6 and 3.0 Ma mainly from deposits at Laetoli (Tanzania) and Hadar (Ethiopia). The phylogenetic relationship of these two ‘species’ is hypothesized as ancestor–descendant. However, the lack of fossil evidence from the time between 3.6 and 3.9 Ma has been one of its weakest points. Recent fieldwork in the Woranso-Mille study area in the Afar region of Ethiopia has yielded fossil hominids dated between 3.6 and 3.8 Ma. These new fossils play a significant role in testing the proposed relationship between Au. anamensis and Au. afarensis. The Woranso-Mille hominids (3.6–3.8 Ma) show a mosaic of primitive, predominantly Au. anamensis-like, and some derived (Au. afarensis-like) dentognathic features. Furthermore, they show that, as currently known, there are no discrete and functionally significant anatomical differences between Au. anamensis and Au. afarensis. Based on the currently available evidence, it appears that there is no compelling evidence to falsify the hypothesis of ‘chronospecies pair’ or ancestor–descendant relationship between Au. anamensis and Au. afarensis. Most importantly, however, the temporally and morphologically intermediate Woranso-Mille hominids indicate that the species names Au. afarensis and Au. anamensis do not refer to two real species, but rather to earlier and later representatives of a single phyletically evolving lineage. However, if retaining these two names is necessary for communication purposes, the Woranso-Mille hominids are best referred to as Au. anamensis based on new dentognathic evidence.