Mapping sexual dimorphism signal in the human cranium.

The study of sexual dimorphism in human crania has important applications in the fields of human evolution and human osteology. Current, the identification of sex from cranial morphology relies on manual visual inspection of identifiable anatomical features, which can lead to bias due to user's expertise. We developed a landmark-based approach to automatically map the sexual dimorphism signal on the human cranium. We used a sex-known sample of 228 individuals from different geographical locations to identify which cranial regions are most sexually dimorphic taking into account shape, form and size. Our results, which align with standard protocols, show that glabellar and supraciliary regions, the mastoid process and the nasal region are the most sexually dimorphic traits (with an accuracy of 73%). The accuracy increased to 77% if they were considered together. Surprisingly the occipital external protuberance resulted to be not sexually dimorphic but mainly related to variations in size. Our approach here applied could be expanded to map other variable signals on skeletal morphology.

Human remains from Arma di Nasino (Liguria) provide novel insights into the paleoecology of early Holocene foragers in northwestern Italy.

We report the discovery and analysis of new Mesolithic human remains-dated to ca. 10,200-9000 cal. BP-from Arma di Nasino in Liguria, northwestern Italy, an area rich in Upper Paleolithic and Neolithic attestations, but for which little information on Early Holocene occupation was available. The multi-proxy isotopic profile of the two individuals reveals that-despite the proximity of the site to the Mediterranean seashore and the use of shellfish as decorative elements in burials-the ecology of these foragers was based on the exploitation of high-altitude resources, presumably in the nearby western Alps. This constitutes the first direct evidence in northwestern Italy of a significant ecological shift towards higher altitudes following deglaciation, especially when compared to isotopic data of the Late Pleistocene hunter-gatherers from the nearby site of Arene Candide Cave, who exploited terrestrial resources nearer to the coast and at lower altitudes. While the biochemistry of Nasino's skeletal assemblage revealed new details on Early Holocene lifeways in the area, the osteobiography of one individual offers glimpses into the life experience of a specific female forager, depicting a scenario of early skeletal trauma, developmental disturbances, long-term impairments, and resilience amongst the last European hunter-gatherers.

Descriptive catalog of Homo naledi dental remains from the 2013 to 2015 excavations of the Dinaledi Chamber, site U.W. 101, within the Rising Star cave system, South Africa.

More than 150 hominin teeth, dated to ∼330-241 thousand years ago, were recovered during the 2013-2015 excavations of the Dinaledi Chamber of the Rising Star cave system, South Africa. These fossils comprise the first large single-site sample of hominin teeth from the Middle Pleistocene of Africa. Though scattered remains attributable to Homo sapiens, or their possible lineal ancestors, are known from older and younger sites across the continent, the distinctive morphological feature set of the Dinaledi teeth supports the recognition of a novel hominin species, Homo naledi. This material provides evidence of African Homo lineage diversity that lasts until at least the Middle Pleistocene. Here, a catalog, anatomical descriptions, and details of preservation and taphonomic alteration are provided for the Dinaledi teeth. Where possible, provisional associations among teeth are also proposed. To facilitate future research, we also provide access to a catalog of surface files of the Rising Star jaws and teeth.

A multi-proxy bioarchaeological approach reveals new trends in Bronze Age diet in Italy.

This study investigates changes in dietary practices and subsistence strategies in Bronze Age Italy integrating isotopic analyses with archaeobotanical and archaeozoological data. By investigating food habits, we contribute to reconstructing human lifestyles and highlighting possible links with the economic/social organization when the rise of stratified societies and new economic activities affected subsistence practices. Stable isotopes analyses in humans and animals were performed on 6 Italian sites dating from 2300 to 900 cal. BC, followed by a complete review of additional 19 sites, which forms the basis of a diachronic and geographic comparison for Bronze Age Italy. The geographic analysis shows a more varied diet in northern and central Italy, compared to the south. The diachronic analysis highlights the homogeneity of food habits during the Early Bronze Age, contrary to the later phases when an increase in dietary variability and a higher animal protein consumption are revealed. The Middle Bronze Age appears as a pivotal moment in protohistoric societies, a phase of transition. The consumption of different foodstuffs highlights the importance of cultural exchanges, resulting in a sort of "food globalization", although environmental and climatic fluctuations could also have affected dietary patterns, favoring some crops over others.

The DNH 7 skull of Australopithecus robustus from Drimolen (Main Quarry), South Africa.

Although the early hominin species Australopithecus robustus has been known for more than eight decades and is represented by hundreds of fossils from sites in South Africa, a complete, well-preserved skull has been elusive. DNH 7, an adult cranium and mandible from the Drimolen site, was identified, on the basis of its small size, as a presumptive female of A. robustus. Here, we provide a detailed comparative description of the specimen. In cranial, facial, and dental size, DNH 7 is confirmed to lie at the extreme small end of the A. robustus range of variation, along with a few fragmentary maxillofacial specimens from Swartkrans. In addition, relative to the classically derived craniofacial features of the Swartkrans+Kromdraai portions of the A. robustus hypodigm, primitive anatomy pervades the DNH 7 face, braincase, and cranial base. Taken together, these pieces of evidence place DNH 7 in a previously unfilled position on the robust Australopithecus morphocline, where the specimen highlights the morphological distinctions between southern and eastern African species of this group and epitomizes the anatomy expected of the group's last common ancestor.

Exploring late Paleolithic and Mesolithic diet in the Eastern Alpine region of Italy through multiple proxies.

OBJECTIVES: The analysis of prehistoric human dietary habits is key for understanding the effects of paleoenvironmental changes on the evolution of cultural and social human behaviors. In this study, we compare results from zooarchaeological, stable isotope and dental calculus analyses as well as lower second molar macrowear patterns to gain a broader understanding of the diet of three individuals who lived between the end of the Late Pleistocene and the Early Holocene (ca., 17-8 ky cal BP) in the Eastern Alpine region of Italy. MATERIALS AND METHODS: We analyze individuals buried at the sites of Riparo Tagliente (Verona), Riparo Villabruna, and Mondeval de Sora (Belluno). The three burials provide a unique dataset for diachronically exploring the influence of climatic changes on human subsistence strategies. RESULTS: Isotopic results indicate that all individuals likely relied on both terrestrial and freshwater animal proteins. Even though dental calculus analysis was, in part, hindered by the amount of mineral deposit available on the teeth, tooth macrowear study suggests that the dietary habits of the individuals included plant foods. Moreover, differences in macrowear patterns of lower second molars have been documented between Neanderthals and modern humans in the present sample, due to a prevalence of Buccal wear among the former as opposed to higher values of Lingual wear in modern human teeth. DISCUSSION: Isotopic analyses have emphasized the contribution of animal proteins in the diet of the three foragers from the Eastern Alpine region. The possible intake of carbohydrate-rich plant foods, suggested by the retrieval of plant remains in dental calculus, is supported by the signal of macrowear analysis. Moreover, the latter method indicates that the distribution of macrowear in lower second molars (M2 s) allows us to discriminate between Neanderthals and modern humans within the present reference sample. Overall, our results show these three prehistoric hunter-gatherers were well adapted to the environment in which they lived exploiting many natural resources.

Comparative morphometric analyses of the deciduous molars of Homo naledi from the Dinaledi Chamber, South Africa.

OBJECTIVES: The purpose of this study is to help elucidate the taxonomic relationship between Homo naledi and other hominins. MATERIALS AND METHODS: Homo naledi deciduous maxillary and mandibular molars from the Dinaledi Chamber, South Africa were compared to those of Australopithecus africanus, Australopithecus afarensis, Paranthropus robustus, Paranthropus boisei, early Homo sp., Homo erectus, early Homo sapiens, Upper Paleolithic H. sapiens, recent southern African H. sapiens, and Neanderthals by means of morphometric analyses of crown outlines and relative cusp areas. The crown shapes were analyzed using elliptical Fourier analyses followed by principal component analyses (PCA). The absolute and relative cusp areas were obtained in ImageJ and compared using PCA and cluster analyses. RESULTS: PCA suggests that the crown shapes and relative cusp areas of mandibular molars are more diagnostic than the maxillary molars. The H. naledi deciduous mandibular first and second molar (dm1 and dm2 ) do not have a strong affinity to any taxon in the comparative sample in all analyses. While the H. naledi dm2 plots as an outlier in the relative cusp analysis, the H. naledi specimen fall closest to Australopithecus due to their relatively large metaconid, a primitive trait for the genus Homo. Although useful for differentiating Neanderthals from recent southern African H. sapiens and UP H. sapiens, the PCA of the relative cusp areas suggests that the deciduous maxillary second molars (dm2 ) do not differentiate other groups. The three H. naledi dm2 cuspal areas are variable and fall within the ranges of other Homo, as well as Australopithecus, and Paranthropus suggesting weak diagnostic utility. DISCUSSION: This research provides another perspective on the morphology of, and variation within, H. naledi. The H. naledi deciduous molars do not consistently align with any genus or species in the comparative sample in either the crown shape or relative cusp analyses. This line of inquiry is consistent with other cranial and postcranial studies suggesting that H. naledi is unique.

In situ observations on the dentition and oral cavity of the Neanderthal skeleton from Altamura (Italy).

The Neanderthal specimen from Lamalunga Cave, near Altamura (Apulia, Italy), was discovered during a speleological survey in 1993. The specimen is one of the most complete fossil hominins in Europe and its state of preservation is exceptional, although it is stuck in calcareous concretions and the bones are mostly covered by calcite depositions. Nevertheless, it is possible to carry out some observations on craniodental features that have not previously been described. In this work, we present an account of the oral cavity, made possible by the use of a videoscope, which allowed us to reach some hidden parts of the mandible and palate. This is the first detailed overview of the teeth and maxillary bones of the Neanderthal skeleton from Altamura. The dentition is almost complete. However, two teeth (upper right P3 and upper left M1) were lost ante mortem and four teeth (lower right I1 and P3 and lower left I1 and I2) were lost most probably post mortem. Dental wear is marked. The erupted M3s and the inversion of the compensating curve of Wilson in the M1s and M2s but not in the M3s suggest that the individual is fully adult, but not old. Although most of the teeth have their roots exposed for several millimeters, the periodontal bone appears to be in good condition overall, except in correspondence of the two ante-mortem tooth losses. X-rays of the anterior teeth show a periapical lesion, probably linked to the advanced dental wear. We also observed a weak expression of taurodontism in the posterior dentition and the presence of a retromolar space, features consistent with an attribution to the Neanderthal hypodigm; this attribution is also supported by aspects of the cranial morphology, the morphometric analysis of the scapula and preliminary mtDNA data. There is also a well-developed palatine torus, to the best of our knowledge a feature not previously described in Neanderthals.

The functional role of the Carabelli trait in early and late hominins.

The Carabelli trait is a dental feature that forms along the lingual margin of the protocone of deciduous and permanent maxillary molars. It is variably expressed, ranging from a small pit or furrow to a large cusp, and its development seems to be associated with crown size and molar cusp spatial configuration. The degree of expression of the Carabelli trait differs systematically between hominin taxa, and for this reason, it has been used extensively in the reconstruction of their phylogeny. However, the functional implications of having a large Carabelli trait remain unclear. In this study, we analyze the macrowear pattern of maxillary molars of early and late hominins using the occlusal fingerprint analysis method, an approach based on digital models of teeth that helps in reconstructing occlusal dynamics occurring during mastication. Tooth crowns with a small Carabelli cusp generally exhibit larger wear contact areas that extended cervically, while two additional new occlusal contact areas are common in teeth characterized by a large Carabelli cusp. These wear areas are created at the beginning of the chewing cycle, when occluding with the slopes of the lingual groove of the lower molars, between the metaconid and entoconid cusps. Advancing tooth wear leads to a slight enlargement of Carabelli occlusal contacts increasing their functional area. A steep inclination could be mechanically important in food reduction and in balancing the functional load distribution during mastication contacts. Steep wear areas are particularly developed in primates that process foods characterized by tough and fibrous textural properties. Future biomechanical and microwear texture analyses could provide additional information on the mechanical adaptation of this dental trait.

Contemporaneity of Australopithecus, Paranthropus, and early Homo erectus in South Africa.

Understanding the extinction of Australopithecus and origins of Paranthropus and Homo in South Africa has been hampered by the perceived complex geological context of hominin fossils, poor chronological resolution, and a lack of well-preserved early Homo specimens. We describe, date, and contextualize the discovery of two hominin crania from Drimolen Main Quarry in South Africa. At ~2.04 million to 1.95 million years old, DNH 152 represents the earliest definitive occurrence of Paranthropus robustus, and DNH 134 represents the earliest occurrence of a cranium with clear affinities to Homo erectus These crania also show that Homo, Paranthropus, and Australopithecus were contemporaneous at ~2 million years ago. This high taxonomic diversity is also reflected in non-hominin species and provides evidence of endemic evolution and dispersal during a period of climatic variability.

Insights on patterns of developmental disturbances from the analysis of linear enamel hypoplasia in a Neolithic sample from Liguria (northwestern Italy).

OBJECTIVE: To assess developmental disturbances through the analysis of linear enamel hypoplasia (LEH) frequency and to infer environmental stress and life history within Neolithic communities from Liguria (Italy). MATERIALS: 43 unworn/minimally worn permanent anterior teeth of 13 individuals recovered from nearby caves and dated to c. 4800-4400 cal. BCE. METHODS: LEH defects were identified with high-resolution macrophotos of dental replicas, age at LEH was calculated via perikymata counts. LEH defects matched between two or more teeth were considered as systemic disturbances. LEH frequency by age classes was analyzed via GLZ and Friedman ANOVA. RESULTS: Number of matched defects per individual range between 2-12. The mean LEH per individual was highest in the 2.5-2.99 age category, with a significant increase relative to earlier growth stages, followed by a decline. CONCLUSION: LEH may reflect life-history in the local ecology of Neolithic Liguria, where several individuals with osteoarticular tuberculosis have been recorded. Disease burden may have triggered developmental disturbances around the time of weaning. Age at first defect was negatively correlated with age at death and positively with the total number of defects, suggesting that early stress may have affected survivorship. SIGNIFICANCE: The study contributes to the reconstruction of ecological pressures among Neolithic people of Liguria, and informs on environmental challenges during the Neolithic adaptive expansion. LIMITATIONS: The visual examination of macrophotos is prone to observer error; mid-crown tends to display more visible LEH due to tooth architecture. SUGGESTIONS FOR FURTHER RESEARCH: Apply different quantitative methods to examine severity and duration of disturbances.

The deciduous dentition of Homo naledi: A comparative study.

In 2013, 2014 new hominin remains were uncovered in the Dinaledi chamber of the Rising Star cave system in South Africa. In 2015 Berger and colleagues identified these remains as belonging to a new species Homo naledi (Berger et al., 2015). Subsequent comparative studies of the skull, postcrania and permanent dentition have supported this taxonomic affiliation (Harcourt-Smith et al., 2015; Kivell et al., 2015; Irish et al., 2018). The deciduous teeth can offer unique insights into hominin evolution. Due to their early onset and rapid development their morphology is thought to be under stronger genetic control and less influenced by environment than are the permanent teeth. In this study we compared the H. naledi deciduous teeth from the 2013-2014 excavations to samples representing much of the hominin clade including Australopithecus afarensis, Australopithecus africanus, Paranthropus boisei, Paranthropus robustus, early Homo, Homo antecessor, Homo erectus s.l., Homo floresiensis, Middle Pleistocene Homo, Homo neanderthalensis, early Homo sapiens and recent H. sapiens from Sub-Saharan Africa. By making such a broad morphological comparison, we aimed to contextualize the Dinaledi hominins and to further assess the validity of their taxonomic assignment. Our analysis of the deciduous teeth revealed a unique combination of features that mirror (but also expand) that found in the permanent teeth. This mosaic includes an asymmetrical lower canine with a distal tubercle, an upper first molar with a large hypocone and epicrista associated with a mesial cuspule, a molarized lower first molar resembling Paranthropus, and upper and lower second molars that resemble later Homo in their lack of accessory cusps. The unique combination of deciduous dental characters supports previous studies assigning H. naledi to a new species, although its phylogenetic position vis-à-vis other Homo species remains ambiguous.

Root caries on a Paranthropus robustus third molar from Drimolen.

OBJECTIVES: Dental caries is often perceived as a modern human disease. However, their presence is documented in many early human groups, various nonhuman primates and, increasingly, our hominin ancestors and relatives. In this study, we describe an antemortem lesion on the root of a Paranthropus robustus third molar from Drimolen, South Africa, which likely represents another example of caries in fossil hominins. MATERIALS AND METHODS: The molar, DNH 40, is dated to 2.0-1.5 Ma and displays a lesion on the mesial root surface, extending from the cementoenamel junction 3 mm down toward the apex. The position and severity of the lesion was macroscopically recorded and micro-CT scanned to determine the extent of dentine involvement. RESULTS: A differential diagnosis indicates root caries, as the lesion is indistinguishable from clinical examples. Although necrotic in appearance, external tertiary dentine is evident on a micro CT scan. Gingival recession and/or continuous eruption of the tooth as a result of extensive occlusal wear would have occurred to facilitate caries formation. Therefore, the lesion is likely linked to relative old age of this individual. DISCUSSION: This new example increases the total number of carious lesions described in P. robustus teeth to 10, on occlusal, interproximal, and now, root surfaces. Beyond the consumption of caries-causing food, caries formation would have also required the presence of requisite intraoral cariogenic bacteria in this individual and the species. Of interest, the presence of tertiary dentine on the outward surface suggests the DNH 40 lesion may have been arrested, that is, no longer active, perhaps relating to a change in diet or oral microbiome just prior to the individual's death.

Ages-at-death distribution of the early Pleistocene hominin fossil assemblage from Drimolen (South Africa).

OBJECTIVES: A prevailing hypothesis in paleoanthropology is that early Pleistocene hominin bones were accumulated in South African caves by carnivores, which used those shelters, and the trees surrounding them, as refuge and feeding sites. We tested this hypothesis at the site of Drimolen, by comparing its hominin age-at-death distribution to that of the nearby and roughly contemporaneous site of Swartkrans. MATERIALS AND METHODS: We employed standard dental aging systems in order to categorize the Drimolen hominin teeth into age classes of 5 years each. We then compared the age-at-death distribution for Drimolen with the published data available for the Swartkrans hominins. RESULTS: Age-at-death distributions indicate that the age category "young adults" is the best represented age category at Swartkrans and the most poorly represented one at Drimolen. Moreover, Drimolen has a preponderance of infant specimens. Both sites have a low frequency of old adult specimens. CONCLUSIONS: Differences observed in frequencies of the age-at-death categories suggest different mechanisms of hominin skeletal accumulation at Drimolen and Swartkrans. Swartkrans' frequency curve reflects mortality in a population subjected to predation and is thus consistent with the carnivore-accumulating hypothesis. In contrast, the Drimolen curve is similar to that of wild populations of living apes. Living primates have been observed exploiting caves as sleeping shelters, for nutritional, security, drinking, and thermoregulatory purposes. We suggest that similar cave use by Pleistocene hominins can explain, in large part, the accumulation of hominin bones at Drimolen. Such a conclusion is another illustration of the growing awareness that a "one-size-fits-all" taphonomic model for South African early Pleistocene hominin sites is probably insufficient.

From unknown to known: Identification of the remains at the mausoleum of fosse Ardeatine.

During the Second World War, on 24th March 1944, 335 Italians were massacred near Rome by the occupying forces of Nazi Germany. Four months later forensic examination led to the identification of 323 out of 335 victims. After approximately 60 years, the identification of the remaining unidentified twelve victims began with anthropological and genetic analysis carried out by a team of Italian forensic experts. Anthropological analysis was performed in field in order to confirm the sex of each victim and verify the presence of only one individual in each grave for a correct sampling. Selected bone fragments for each individual were then collected and transferred to the laboratory for genetic analysis. Although the anthropological ante mortem information was limited, morphological and metrical data was collected for a possible future identification of the victims. Subsequently, the typing of autosomal loci, Y-STR and mtDNA D-loop region of all bone and available reference samples was conducted. LR and cumulative LRs obtained from autosomal STR and Y-STR results confirmed the alleged relationship between three victims and their relatives with values over 104 (one sample) and 106 (two samples). Therefore, the genetic analysis offered the families the possibility of replacing the number of the grave with the name of the victim.

Human deciduous teeth from the Middle Stone Age layers of Sibudu Cave (South Africa).

In the African Pleistocene, the fossil evidence for early Homo sapiens populations is still relatively limited. Here we present two additional specimens (two deciduous teeth) recovered from the Middle Stone Age (MSA) deposits of Sibudu Cave (KwaZulu-Natal, South Africa). We describe their morphology and metrics, using three-dimensional models of the teeth obtained from high-resolution micro-CT images. The first specimen is a Ldm1 (HUM. TO 1) recovered in the BS5 layer dated 77.3±2.7 ka, and associated with stone tools assigned to the "pre-Still Bay" assemblage. The other specimen is a Rdi1 (HUM. TO 2) coming from the Pinkish Grey Sand (PGS) layer, dated 64.7±2.3 ka, and associated with a Howieson's Poort industry. Both teeth are well preserved, with minor post mortem cracks not affecting the overall morphology, and they comprise the intact, worn crown and the remnants of the roots, naturally resorbed. A large carious lesion occupies most of the distal face and part of the occlusal surface in the Ldm1; also a chip of enamel is missing from the disto-buccal corner. For both teeth, we compared mesio-distal (MD) and bucco-lingual (BL) diameters with those of other Late Pleistocene deciduous teeth and extant Homo sapiens. The analysis has shown that the teeth are comparable in size with the other MSA specimens described in the literature.

The physiological linkage between molar inclination and dental macrowear pattern.

OBJECTIVES: Exact symmetry and perfect balance between opposite jaw halves, as well as between antagonistic teeth, is not frequently observed in natural masticatory systems. Research results show that asymmetry in our body, skull, and jaws is often related to genetic, epigenetic, environmental and individual ontogenetic factors. Our study aims to provide evidence for a significant link between masticatory asymmetry and occlusal contact between antagonist teeth by testing the hypothesis that tooth inclination is one of the mechanisms driving distribution of wear in masticatory phases in addition to dietary and cultural habits. MATERIALS AND METHODS: The present work investigates the relationship between dental macrowear patterns and tooth inclinations on a sample of complete maxillary and mandibular 3D models of dental arches from 19 young and adult Yuendumu Aboriginal individuals. The analysis was carried out on first molars (M1) from all quadrants. Occlusal Fingerprint Analysis was used for the quantification of macrowear patterns, and 2D cross-sectional geometric analysis was carried out to investigate asymmetry in dental arches. RESULTS: The asymmetry is highly variable on both arches, and it is associated with differences in the inclination of upper M1 crowns. Each molar has variable inclination (buccal/lingual) which influence tooth to tooth contact, producing greater or lesser variation in wear pattern. Interindividual variability of morphological variation of the occlusal relationship has to be considered in macrowear analysis. DISCUSSION: Our results suggest that overall asymmetry in the masticatory apparatus in modern humans affects occlusal contact areas between antagonist teeth influencing macrowear and chewing efficiency during ontogeny.

Reproducing the internal and external anatomy of fossil bones: Two new automatic digital tools.

OBJECTIVES: We present two new automatic tools, developed under the R environment, to reproduce the internal and external structures of bony elements. The first method, Computer-Aided Laser Scanner Emulator (CA-LSE), provides the reconstruction of the external portions of a 3D mesh by simulating the action of a laser scanner. The second method, Automatic Segmentation Tool for 3D objects (AST-3D), performs the digital reconstruction of anatomical cavities. MATERIALS AND METHODS: We present the application of CA-LSE and AST-3D methods to different anatomical remains, highly variable in terms of shape, size and structure: a modern human skull, a malleus bone, and a Neanderthal deciduous tooth. Both methods are developed in the R environment and embedded in the packages "Arothron" and "Morpho," where both the codes and the data are fully available. RESULTS: The application of CA-LSE and AST-3D allows the isolation and manipulation of the internal and external components of the 3D virtual representation of complex bony elements. In particular, we present the output of the four case studies: a complete modern human endocast and the right maxillary sinus, the dental pulp of the Neanderthal tooth and the inner network of blood vessels of the malleus. DISCUSSION: Both methods demonstrated to be much faster, cheaper, and more accurate than other conventional approaches. The tools we presented are available as add-ons in existing software within the R platform. Because of ease of application, and unrestrained availability of the methods proposed, these tools can be widely used by paleoanthropologists, paleontologists and anatomists.