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.

Genomic inference of a severe human bottleneck during the Early to Middle Pleistocene transition

Population size history is essential for studying human evolution. However, ancient population size history during the Pleistocene is notoriously difficult to unravel. In this study, we developed a fast infinitesimal time coalescent process (FitCoal) to circumvent this difficulty and calculated the composite likelihood for present-day human genomic sequences of 3154 individuals. Results showed that human ancestors went through a severe population bottleneck with about 1280 breeding individuals between around 930,000 and 813,000 years ago. The bottleneck lasted for about 117,000 years and brought human ancestors close to extinction. This bottleneck is congruent with a substantial chronological gap in the available African and Eurasian fossil record. Our results provide new insights into our ancestry and suggest a coincident speciation event.

Virtual excavation and analysis of the early Neanderthal cranium from Altamura (Italy)

Complete Neanderthal skeletons are almost unique findings. A very well-preserved specimen of this kind was discovered in 1993 in the deepest recesses of a karstic system near the town of Altamura in Southern Italy. We present here a detailed description of the cranium, after we virtually extracted it from the surrounding stalagmites and stalactites. The morphology of the Altamura cranium fits within the Neanderthal variability, though it retains features occurring in more archaic European samples. Some of these features were never observed in Homo neanderthalensis, i.e. in fossil specimens dated between 300 and 40 ka. Considering the U-Th age we previously obtained (>130 ka), the morphology of Altamura suggests that the archaic traits it retains may have been originated by geographic isolation of the early Neanderthal populations from Southern Italy.

Pan-Africanism vs. single-origin of Homo sapiens: Putting the debate in the light of evolutionary biology

The scenario of Homo sapiens origin/s within Africa has become increasingly complex, with a pan-African perspective currently challenging the long-established single-origin hypothesis. In this paper, we review the lines of evidence employed in support of each model, highlighting inferential limitations and possible terminological misunderstandings. We argue that the metapopulation scenario envisaged by pan-African proponents well describes a mosaic diversification among late Middle Pleistocene groups. However, this does not rule out a major contribution that emerged from a single population where crucial derived features-notably, a globular braincase-appeared as the result of a punctuated, cladogenetic event. Thus, we suggest that a synthesis is possible and propose a scenario that, in our view, better reconciles with consolidated expectations in evolutionary theory. These indicate cladogenesis in allopatry as an ordinary pattern for the origin of a new species, particularly during phases of marked climatic and environmental instability.

The Thorny Issue of African Porcupines: a New Mandible of Hystrix makapanensis from Olduvai Gorge (Tanzania) and Rediagnosis of the Species

Several porcupine taxa are reported from the middle Miocene to the early Holocene in the Old World. Among these, five species of the subfamily Hystricinae occurred in Africa approximately in the last 6 Ma: the extinct Hystrix makapanensis, Hystrix leakeyi, and Xenohystrix crassidens and the still living Hystrix africaeaustralis and Hystrix cristata. The large-sized H. makapanensis is reported from numerous sites in East and South Africa between the early Pliocene and Early Pleistocene. In this paper, we describe a new mandible of H. makapanensis from the world-renowned Tanzanian paleontological and archeological site of Olduvai Gorge (HWK West; lowermost Bed II; ca. 1.8-1.7 Ma). The discovery of the new mandible triggered a comprehensive review of the entire African record of H. makapanensis. In particular, we describe or re-analyze the samples from South Africa (Makapansgat Limeworks, Gondolin, Kromdraai, Swartkrans, and Sterkfontein), Tanzania (Olduvai and Laetoli), Ethiopia (Omo Shungura and Hadar), and Kenya (Chemeron), enriching the quantity of specimens confidently referable to this species and above all improving the information on its craniodental anatomy. On this basis, we: (1) propose an emended diagnosis of H. makapanensis; (2) point out the morphological and biometric differences between H. makapanensis and other African Hystricinae (also in terms of body mass); and (3) broaden the knowledge on the geographical and chronological distribution of this extinct species.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10914-021-09588-z.

Bone density and genomic analysis unfold cold adaptation mechanisms of ancient inhabitants of Tierra del Fuego

The Fuegians, ancient inhabitants of Tierra del Fuego, are an exemplary case of a cold-adapted population, since they were capable of living in extreme climatic conditions without any adequate clothing. However, the mechanisms of their extraordinary resistance to cold remain enigmatic. Brown adipose tissue (BAT) plays a crucial role in this kind of adaptation, besides having a protective role on the detrimental effect of low temperatures on bone structure. Skeletal remains of 12 adult Fuegians, collected in the second half of XIX century, were analyzed for bone mineral density and structure. We show that, despite the unfavorable climate, bone mineral density of Fuegians was close to that seen in modern humans living in temperate zones. Furthermore, we report significant differences between Fuegians and other cold-adapted populations in the frequency of the Homeobox protein Hox-C4 (HOXC4) rs190771160 variant, a gene involved in BAT differentiation, whose identified variant is predicted to upregulate HOXC4 expression. Greater BAT accumulation might therefore explain the Fuegians extreme cold-resistance and the protection against major cold-related damage. These results increase our understanding of how ecological challenges have been important drivers of human–environment interactions during Humankind history.

Gastrointestinal infection in Italy during the Roman Imperial and Longobard periods: A paleoparasitological analysis of sediment from skeletal remains and sewer drains

OBJECTIVE

This study aims to investigate parasitic infection in Italy during the Roman period (27 BCE-476 CE) and subsequent Longobard (Lombard) period (6th-8th CE).

MATERIALS

Sediment samples from drains and burials from Roman Imperial-period sites in Italy (Lucus Feroniae, Oplontis, Vacone, and Vagnari), Late Antique and Longobard-period burials at Selvicciola (ca. 4th-8th CE), and Longobard-period burials at Vacone and Povegliano Veronese.

METHODS

Microscopy was used to identify helminth eggs and enzyme-linked immunosorbent assay (ELISA) to detect protozoan antigens.

RESULTS

Roundworm and whipworm were found in pelvic sediment from Roman-period burials, while roundworm and the protozoan Giardia duodenalis were identified in Roman-period drains. In pelvic sediment from the Late Antique through Longobard periods, roundworm and Taenia tapeworm eggs were identified.

CONCLUSIONS

Fecal-oral parasites were found throughout Imperial Roman Italy, suggesting that gastrointestinal infections caused a significant disease burden. In the Longobard period we see continuity in transmission of fecal-oral parasites, and the appearance of zoonotic parasites acquired from eating undercooked meat.

SIGNIFICANCE

A wealth of information exists about certain diseases in the Roman period, but relatively little is known about intestinal parasites in Italy during the Roman and Longobard periods. This is the first evidence for Giardia in Roman period Italy, and for any parasites in the Longobard period in Italy.

LIMITATIONS

Low egg concentrations and lack of controls for some samples makes it difficult to differentiate true infections from environmental contamination in some cases.

SUGGESTIONS FOR FUTURE RESEARCH

Continual study of samples from Roman and Longobard period Italy.

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.

Digital imaging techniques applied to a case of concha bullosa from an early medieval funerary area in central Italy

OBJECTIVE

Concha bullosa is a rather common condition of the nasal turbinates, rarely reported in archaeological skeletal collections. This paper examines a case of concha bullosa as seen in a female cranium from a burial in central Italy, dated to the Longobard domination in the Peninsula (mid-7th- early 8th century CE).

MATERIALS

The individual under investigation (T86/17) comes from the funerary area of Selvicciola, located near the town of Viterbo in northern Latium, Italy.

METHODS

The skeleton was macroscopically examined. We analyzed the CT-scans of the defect by applying innovative R-based virtual tools.

RESULTS

It was possible to calculate the inner volume of the concha bullosa and to provide a 3D visual assessment of its shape.

CONCLUSIONS

Its size and shape suggest that the individual had this condition for a considerable period of time, during which its presence may have had affected her daily activities and health status.

SIGNIFICANCE

An under-represented paleopathological defect is examined for the first time through a virtual approach aimed at visualizing its shape and the assessment of its volume. New methods of 3D based virtual assessment can increase the informative value of defects.

SUGGESTIONS FOR FURTHER RESEARCH

Techniques used in this assessment should be considered as an evaluative tool for other conditions when macroscopic and radiographic imaging are limited.

Strontium and oxygen isotopes as indicators of Longobards mobility in Italy: an investigation at Povegliano Veronese

The arrival of the Longobards in Northern Italy in 568 CE marked a period of renewed political stability in the Peninsula after the collapse of the Western Roman Empire. The trajectory of the spread of Longobards in Italy across the Alps and into the South is known from many literary sources. However, their mobility and residence patterns at a population level remain to be fully understood. Here we present a multi-isotopic analysis (⁸⁷Sr/⁸⁶Sr and ¹⁸O/¹⁶O) of 39 humans and 14 animals buried at the Longobard necropolis of Povegliano Veronese (VR, Italy; 6th-8th century CE), to address mode and tempo of the spread of this population in the Peninsula. The geographical location of Povegliano Veronese plays a key role: the site lies along the Via Postumia, which was one of the main ancient Roman roads of Northern Italy, representing an important route in post-classical Italy. The integration of isotopic data with the archaeological evidence allowed us to determine the presence of individuals from at least three different regions of origin, building a diachronic map of the dynamics of mobility of this group in northern Italy.

Locomotion, posture, and the foramen magnum in primates: Reliability of indices and insights into hominin bipedalism

The position (FMP) and orientation (FMO) of the foramen magnum have been used as proxies for locomotion and posture in extant and extinct primates. Several indices have been designed to quantify FMP and FMO but their application has led to conflicting results. Here, we test six widely used indices and two approaches (univariate and multivariate) for their capability to discriminate between postural and locomotor types in extant primates and fossil hominins. We then look at the locomotion of australopithecines and Homo on the base of these new findings. The following measurements are used: the opisthocranion-prosthion (OP-PR) and the opisthocranion-glabella (OP-GL) indices, the basion-biporion (BA-BP) and basion-bicarotid chords, the foramen magnum angle (FMA), and the basion-sphenoccipital ratio. After exploring the indices variability using principal component analysis, pairwise comparisons are performed to test for the association between each index and the locomotor and postural habits. Cranial size and phylogeny are taken into account. Our analysis indicates that none of the indices or approaches provides complete discrimination across locomotor and postural categories, although some differences are highlighted. FMA and BA-BP distinguish respectively obligate and facultative bipeds from all other groups. For what concerns posture, orthogrades and pronogrades differ with respects to OP-PR, OP-GL, and FMA. Although the multivariate approach seems to have some discrimination power, the results are most likely driven by facial and neurocranial variability embedded in some of the indices. These results demonstrate that indices relying on the anteroposterior positioning of the foramen may not be appropriate proxies for locomotion among primates. The assumptions about locomotor and postural habits in fossil hominins based on foramen magnum indices should be revised in light of these new findings.

Contextual factors modulate risk preferences in adult humans

Humans have generally been considered risk averse for gains. Yet, growing evidence shows that risk preferences may change across reward currencies and depend on the type of tasks used to measure them. Here, we examined how context affects human risk preferences to shed light on the psychological mechanisms underlying human decision-making under risk. Participants were presented with a descriptive risky choice task involving repeated choices between real options and they were provided with trial-by-trial feedback. We manipulated the type of reward and, for the first time, the format of the choice stimuli. Options were either 2D computer-based images or concrete 3D objects, and participants received food or money as reward. First, we found that participants were more risk-seeking for food compared to money, suggesting that people treat money differently from consumable rewards. Second, we found that people were more risk-seeking when they made choices between concrete 3D objects than between 2D computer-based images. Our results strengthened the evidence that human choice patterns may change depending on the context and, for the first time, showed that the format of the choice stimuli does affect risk preferences, an important consideration for future research.

Touch improves visual discrimination of object features in capuchin monkeys (Sapajus spp.)

Primates perceive many object features through vision and touch. To date, little is known on how the synergy of these two sensory modalities contributes to enhance object recognition. Here, we investigated in capuchin monkeys (N = 12) whether manipulating objects and retaining tactile information enhanced visual recognition of geometrical object properties on different scales. Capuchins were trained to visually select the rewarded one of two objects differing in size, shape (larger-scale) or surface structure (smaller-scale). Objects were explored in two experimental conditions: the Sight condition prevented capuchins from touching the chosen object; the Sight and Touch condition allowed them to touch the selected object. Our results indicated that tactile information increased the capuchins' learning speed for visual discrimination of object features. Moreover, the capuchins' learning speed was higher in both size and shape discrimination compared to surface discrimination regardless of the availability of tactile input. Overall, our data demonstrated that the acquisition of tactile information about object features was advantageous for the capuchins and allowed them to achieve high levels of visual accuracy faster. This suggests that information from touch potentiated object recognition in the visual modality.

Macroevolutionary trends of brain mass in Primates

A distinctive trait in primate evolution is the expansion in brain mass. The potential drivers of this trend and how and whether encephalization influenced diversification dynamics in this group are hotly debated. We assembled a phylogeny accounting for 317 primate species, including both extant and extinct taxa, to identify macroevolutionary trends in brain mass evolution. Our findings show that Primates as a whole follow a macroevolutionary trend for an increase in body mass, relative brain mass and speciation rate over time. Although the trend for increased encephalization (brain mass) applies to all Primates, hominins stand out for their distinctly higher rates. Within hominins, this unique trend applies linearly over time and starts with Australopithecus africanus. The increases in both speciation rate and encephalization begin in the Oligocene, suggesting the two variables are causally associated. The substitution of early, stem Primates belonging to plesiadapiforms with crown Primates seems to be responsible for these macroevolutionary trends. However, our findings also suggest that cognitive capacities favoured speciation in hominins.

Ancestral mitochondrial N lineage from the Neolithic 'green' Sahara

Because Africa’s climate hampers DNA preservation, knowledge of its genetic variability is mainly restricted to modern samples, even though population genetics dynamics and back-migrations from Eurasia may have modified haplotype frequencies, masking ancient genetic scenarios. Thanks to improved methodologies, ancient genetic data for the African continent are now increasingly available, starting to fill in the gap. Here we present newly obtained mitochondrial genomes from two ~7000-year-old individuals from Takarkori rockshelter, Libya, representing the earliest and first genetic data for the Sahara region. These individuals carry a novel mutation motif linked to the haplogroup N root. Our result demonstrates the presence of an ancestral lineage of the N haplogroup in the Holocene “Green Sahara”, associated to a Middle Pastoral (Neolithic) context.

A possible case of mycosis in a post-classical burial from La Selvicciola (Italy)

An examination of an adult male buried from the post-classical necropolis of La Selvicciola (Viterbo, Latium, Italy; 4^th-6^th centuries AD) revealed a series of skeletal lesions. The lesions, both proliferative and lytic, ranging in size from small (around 0.01 mm) to extensive (up to 16.00 mm) pits, occurred at multiple sites. A holistic approach assessed lesion type, frequency and location in a differential diagnosis, which included myeloma, metastatic carcinoma, tuberculosis, leukemia, osteomyelitis, and mycoses. It was concluded that a mycosis, specifically Cryptococcosis, was the most likely cause of these lesions. Both macroscopic analyses and X-ray scans support our diagnosis. We also provide a methodological scheme as a model for examining unknown lesion patterns.

Survival to amputation in pre-antibiotic era: a case study from a Longobard necropolis (6th-8th centuries AD)

The Longobard necropolis of Povegliano Veronese dates from the 6th to the 8th centuries AD. Among the 164 tombs excavated, the skeleton of an older male shows a well-healed amputated right forearm. The orientation of the forearm fracture suggests an angled cut by a single blow. Reasons why a forearm might be amputated include combat, medical intervention, and judicial punishment. As with other amputation cases reported in literature, this one exhibits both healing and osteoblastic response. We argue that the forelimb stump morphology suggests the use of a prosthesis. Moreover, dental modification of RI2 shows considerable wear and smoothing of the occlusal surface, which points to dental use in attaching the prosthesis to the limb. Other indications of how this individual adjusted to his amputated condition includes a slight change in the orientation of the right glenoid fossa surface, and thinning of right humeral cortical bone. This is a remarkable example in which an older male survived the loss of a forelimb in pre-antibiotic era. We link archaeological remains found in the tomb (buckle and knife) with the biological evidence to show how a combined bioarchaeological approach can provide a clearer interpretation of the life history of an individual.

Neandertal Introgression Sheds Light on Modern Human Endocranial Globularity

One of the features that distinguishes modern humans from our extinct relatives and ancestors is a globular shape of the braincase [1-4]. As the endocranium closely mirrors the outer shape of the brain, these differences might reflect altered neural architecture [4, 5]. However, in the absence of fossil brain tissue, the underlying neuroanatomical changes as well as their genetic bases remain elusive. To better understand the biological foundations of modern human endocranial shape, we turn to our closest extinct relatives: the Neandertals. Interbreeding between modern humans and Neandertals has resulted in introgressed fragments of Neandertal DNA in the genomes of present-day non-Africans [6, 7]. Based on shape analyses of fossil skull endocasts, we derive a measure of endocranial globularity from structural MRI scans of thousands of modern humans and study the effects of introgressed fragments of Neandertal DNA on this phenotype. We find that Neandertal alleles on chromosomes 1 and 18 are associated with reduced endocranial globularity. These alleles influence expression of two nearby genes, UBR4 and PHLPP1, which are involved in neurogenesis and myelination, respectively. Our findings show how integration of fossil skull data with archaic genomics and neuroimaging can suggest developmental mechanisms that may contribute to the unique modern human endocranial shape.

Measuring the shape: performance evaluation of a photogrammetry improvement applied to the Neanderthal skull Saccopastore 1

Several digital technologies are nowadays developed and applied to the study of the human fossil record. Here, we present a low-cost hardware implementation of the digital acquisition via photogrammetry, applied to a specimen of paleoanthropological interest: the Neanderthal skull Saccopastore 1. Such implementation has the purpose to semi-automatize the procedures of digital acquisition, by the introduction of an automatically rotating platform users can easily build on their own with minimum costs. We provide all the technical specifications, mostly based on the Arduino UNO™ microcontroller technology, and evaluate the performance and the resolution of the acquisition by comparing it with the CT-scan of the same specimen through the calculation of their shape differences. In our opinion, the replication of the automatic rotating platform, described in this work, may contribute to the improvement of the digital acquisition processes and may represent, in addition, a useful and affordable tool for both research and dissemination.

MicroWeaR: A new R package for dental microwear analysis

Mastication of dietary items with different mechanical properties leaves distinctive microscopic marks on the surface of tooth enamel. The inspection of such marks (dental microwear analysis) is informative about the dietary habitus in fossil as well as in modern species. Dental microwear analysis relies on the morphology, abundance, direction, and distribution of these microscopic marks. We present a new freely available software implementation, MicroWeaR, that, compared to traditional dental microwear tools, allows more rapid, observer error free, and inexpensive quantification and classification of all the microscopic marks (also including for the first time different subtypes of scars). Classification parameters and graphical rendering of the output are fully settable by the user. MicroWeaR includes functions to (a) sample the marks, (b) classify features into categories as pits or scratches and then into their respective subcategories (large pits, coarse scratches, etc.), (c) generate an output table with summary information, and (d) obtain a visual surface-map where marks are highlighted. We provide a tutorial to reproduce the steps required to perform microwear analysis and to test tool functionalities. Then, we present two case studies to illustrate how MicroWeaR works. The first regards a Miocene great ape obtained from through environmental scanning electron microscope, and other a Pleistocene cervid acquired by a stereomicroscope.

Unexpectedly rapid evolution of mandibular shape in hominins

Members of the hominins - namely the so-called 'australopiths' and the species of the genus Homo - are known to possess short and deep mandibles and relatively small incisors and canines. It is commonly assumed that this suite of traits evolved in early members of the clade in response to changing environmental conditions and increased consumption of though food items. With the emergence of Homo, the functional meaning of mandible shape variation is thought to have been weakened by technological advancements and (later) by the control over fire. In contrast to this expectation, we found that mandible shape evolution in hominins is exceptionally rapid as compared to any other primate clade, and that the direction and rate of shape change (from the ape ancestor) are no different between the australopiths and Homo. We deem several factors including the loss of honing complex, canine reduction, and the acquisition of different diets may have concurred in producing such surprisingly high evolutionary rates. This study reveals the evolution of mandibular shape in hominins has strong morpho-functional and ecological significance attached.

Retrodeformation of fossil specimens based on 3D bilateral semi-landmarks: Implementation in the R package "Morpho"

Many fossil specimens exhibit deformations caused by taphonomic processes. Due to these deformations, even important specimens have to be excluded from morphometric analyses, impoverishing an already poor paleontological record. Techniques to retrodeform and virtually restore damaged (i.e. deformed) specimens are available, but these methods genenerally imply the use of a sparse set of bilateral landmarks, ignoring the fact that the distribution and amount of control points directly affects the result of the retrodeformation. We propose a method developed in the R environment and available in the R-package "Morpho" that, in addition to the landmark configurations, also allows using a set of semi-landmarks homogeneously distributed along curves and on surfaces. We evaluated the outcome of the retrodeformation, regarding the number of semi-landmarks used and its robustness against asymmetric noise, based on simulations using a virtually deformed gorilla cranium. Finally, we applied the method to a well-known Neanderthal cranium that exhibits signs of taphonomically induced asymmetry.

Digital reconstruction of the Ceprano calvarium (Italy), and implications for its interpretation

The Ceprano calvarium was discovered in fragments on March 1994 near the town of Ceprano in southern Latium (Italy), embedded in Middle Pleistocene layers. After reconstruction, its morphological features suggests that the specimen belongs to an archaic variant of H. heidelbergensis, representing a proxy for the last common ancestor of the diverging clades that respectively led to H. neanderthalensis and H. sapiens. Unfortunately, the calvarium was taphonomically damaged. The postero-lateral vault, in particular, appears deformed and this postmortem damage may have influenced previous interpretations. Specifically, there is a depression on the fragmented left parietal, while the right cranial wall is warped and angulated. This deformation affected the shape of the occipital squama, producing an inclination of the transverse occipital torus. In this paper, after X-ray microtomography (μCT) of both the calvarium and several additional fragments, we analyze consistency and pattern of the taphonomic deformation that affected the specimen, before the computer-assisted retrodeformation has been performed; this has also provided the opportunity to reappraise early attempts at restoration. As a result, we offer a revised interpretation for the Ceprano calvarium’s original shape, now free from the previous uncertainties, along with insight for its complex depositional and taphonomic history.

Dietary resilience among hunter-gatherers of Tierra del Fuego: Isotopic evidence in a diachronic perspective

The native groups of Patagonia have relied on a hunter-gatherer economy well after the first Europeans and North Americans reached this part of the world. The large exploitation of marine mammals (i.e., seals) by such allochthonous groups has had a strong impact on the local ecology in a way that might have forced the natives to adjust their subsistence strategies. Similarly, the introduction of new foods might have changed local diet. These are the premises of our isotopic-based analysis. There is a large set of paleonutritional investigations through isotopic analysis on Fuegians groups, however a systematic exploration of food practices across time in relation to possible pre- and post-contact changes is still lacking. In this paper we investigate dietary variation in hunter-gatherer groups of Tierra del Fuego in a diachronic perspective, through measuring the isotopic ratio of carbon (∂13C) and nitrogen (∂15N) in the bone collagen of human and a selection of terrestrial and marine animal samples. The data obtained reveal an unexpected isotopic uniformity across prehistoric and recent groups, with little variation in both carbon and nitrogen mean values, which we interpret as the possible evidence of resilience among these groups and persistence of subsistence strategies, allowing inferences on the dramatic contraction (and extinction) of Fuegian populations.

New footprints from Laetoli (Tanzania) provide evidence for marked body size variation in early hominins

Laetoli is a well-known palaeontological locality in northern Tanzania whose outstanding record includes the earliest hominin footprints in the world (3.66 million years old), discovered in 1978 at Site G and attributed to Australopithecus afarensis. Here, we report hominin tracks unearthed in the new Site S at Laetoli and referred to two bipedal individuals (S1 and S2) moving on the same palaeosurface and in the same direction as the three hominins documented at Site G. The stature estimates for S1 greatly exceed those previously reconstructed for Au. afarensis from both skeletal material and footprint data. In combination with a comparative reappraisal of the Site G footprints, the evidence collected here embodies very important additions to the Pliocene record of hominin behaviour and morphology. Our results are consistent with considerable body size variation and, probably, degree of sexual dimorphism within a single species of bipedal hominins as early as 3.66 million years ago.

DOI:http://dx.doi.org/10.7554/eLife.19568.001

Fossil footprints are extremely useful tools in the palaeontological record. Their physical features can help to identify their makers, but can also be used to infer biological information. How did the track-maker move? How large was it? How fast was it going?

Footprints of hominins (namely the group to which humans and our ancestors belong) are pretty rare. Nearly all of the hominin footprints discovered so far are attributed to species of the genus Homo, to which modern humans belong. The only exceptions are the footprints that were discovered in the 1970s at Laetoli (in Tanzania) on a cemented ash layer produced by a volcanic eruption. These are thought to have been made by three members of the hominin species Australopithecus afarensis – the same species as the famous “Lucy” from Ethiopia – around 3.66 million years ago.

The extent to which body shape and size varied between different members of Au. afarensis – for example, between males and females – has been the subject of a long debate among researchers. Based on the skeletal remains found so far in East Africa, some scholars believe that individuals only varied moderately, as in modern humans, while others state that it was pronounced, as in some modern apes like gorillas.

Masao et al. have now unearthed new bipedal footprints from two individuals who were moving on the same surface and in the same direction as the three individuals who made the footprints documented in the 1970s. The estimated height of one of the new individuals (about 1.65 metres) greatly exceeds those previously published for Au. afarensis. This evidence supports the theory that body size varied considerably amongst individuals within the species.

Masao et al. tentatively suggest that the new footprints can be considered as a whole with the 1970s ones. The tall individual may have been the dominant male of a larger group, the others smaller females and juveniles. Thus, considerable differences may have existed between males and females in these remote human ancestors, similar to modern gorillas.

The newly discovered tracks are only 150 metres away from the previously discovered sets of footprints. This leaves open the possibility that additional tracks may be unearthed nearby that will further our knowledge about the variability and behaviour of our extinct ancestors.

DOI:http://dx.doi.org/10.7554/eLife.19568.002

Filling the gap. Human cranial remains from Gombore II (Melka Kunture, Ethiopia; ca. 850 ka) and the origin of Homo heidelbergensis

African archaic humans dated to around 1,0 Ma share morphological affinities with Homo ergaster and appear distinct in cranio-dental morphology from those of the Middle Pleistocene that are referred to Homo heidelbergensis. This observation suggests a taxonomic and phylogenetic discontinuity in Africa that ranges across the Matuyama/Brunhes reversal (780 ka). Yet, the fossil record between roughly 900 and 600 ka is notoriously poor. In this context, the Early Stone Age site of Gombore II, in the Melka Kunture formation (Upper Awash, Ethiopia), provides a privileged case-study. In the Acheulean layer of Gombore II, somewhat more recent than 875 ±10 ka, two large cranial fragments were discovered in 1973 and 1975 respectively: a partial left parietal (Melka Kunture 1) and a right portion of the frontal bone (Melka Kunture 2), which probably belonged to the same cranium. We present here the first detailed description and computer-assisted reconstruction of the morphology of the cranial vault pertaining to these fossil fragments. Our analysis suggest that the human fossil specimen from Gombore II fills a phenetic gap between Homo ergaster and Homo heidelbergensis. This appears in agreement with the chronology of such a partial cranial vault, which therefore represents at present one of the best available candidates (if any) for the origin of Homo heidelbergensis in Africa.

A Human Deciduous Tooth and New 40Ar/39Ar Dating Results from the Middle Pleistocene Archaeological Site of Isernia La Pineta, Southern Italy

Isernia La Pineta (south-central Italy, Molise) is one of the most important archaeological localities of the Middle Pleistocene in Western Europe. It is an extensive open-air site with abundant lithic industry and faunal remains distributed across four stratified archaeosurfaces that have been found in two sectors of the excavation (3c, 3a, 3s10 in sect. I; 3a in sect. II). The prehistoric attendance was close to a wet environment, with a series of small waterfalls and lakes associated to calcareous tufa deposits. An isolated human deciduous incisor (labelled IS42) was discovered in 2014 within the archaeological level 3 coll (overlying layer 3a) that, according to new ⁴⁰Ar/³⁹Ar measurements, is dated to about 583–561 ka, i.e. to the end of marine isotope stage (MIS) 15. Thus, the tooth is currently the oldest human fossil specimen in Italy; it is an important addition to the scanty European fossil record of the Middle Pleistocene, being associated with a lithic assemblage of local raw materials (flint and limestone) characterized by the absence of handaxes and reduction strategies primarily aimed at the production of small/medium-sized flakes. The faunal assemblage is dominated by ungulates often bearing cut marks. Combining chronology with the archaeological evidence, Isernia La Pineta exhibits a delay in the appearance of handaxes with respect to other European Palaeolithic sites of the Middle Pleistocene. Interestingly, this observation matches the persistence of archaic morphological features shown by the human calvarium from the Middle Pleistocene site of Ceprano, not far from Isernia (south-central Italy, Latium). In this perspective, our analysis is aimed to evaluate morphological features occurring in IS42.

The Neanderthal in the karst: First dating, morphometric, and paleogenetic data on the fossil skeleton from Altamura (Italy)

In 1993, a fossil hominin skeleton was discovered in the karst caves of Lamalunga, near Altamura, in southern Italy. Despite the fact that this specimen represents one of the most extraordinary hominin specimens ever found in Europe, for the last two decades our knowledge of it has been based purely on the documented on-site observations. Recently, the retrieval from the cave of a fragment of bone (part of the right scapula) allowed the first dating of the individual, the quantitative analysis of a diagnostic morphological feature, and a preliminary paleogenetic characterization of this hominin skeleton from Altamura. Overall, the results concur in indicating that it belongs to the hypodigm of Homo neanderthalensis, with some phenetic peculiarities that appear consistent with a chronology ranging from 172 ± 15 ka to 130.1 ± 1.9 ka. Thus, the skeleton from Altamura represents the most ancient Neanderthal from which endogenous DNA has ever been extracted.

MODERN BEAMS FOR ANCIENT MUMMIES COMPUTERIZED TOMOGRAPHY OF THE HOLOCENE MUMMIFIED REMAINS FROM WADI TAKARKORI (ACACUS, SOUTH-WESTERN LIBYA; MIDDLE PASTORAL)

The Middle Pastoral human remains from Wadi Takarkori in the Libyan Acacus mountains (Fezzan) are exceptionally preserved partial mummies ranging between 6100 and 5000 uncal years BP; this small sample represents the most ancient of its kind ever found. In this report, we present a survey of the skeletal anatomy of these mummifed corpses, based on high resolution CT-scan data, including a preliminary phenetic interpretation of their cranial morphology.

On the trail of the genus Homo between archaic and derived morphologies

The topic of this review is the evolution of the genus Homo, focusing on evolutionary transitions that occurred during the Early and Middle Pleistocene. Two crucial issues are addressed in particular: 1) the emergence in the Early Pleistocene of the archaic variant of Homo that might represent the last common ancestor before the emergence of at least two (more probably three) geographically distinct trajectories; and (2) the evolution of these derived lineages, ultimately leading to the allopatric speciations of the most encephalised species of Homo: H. neanderthalensis and H. sapiens. In this framework, the time window between 1.0 million years ago (Ma) and 500 thousand years ago (ka) is of crucial importance, since it is probable that a new kind of humanity emerged in this period and then spread across a wide area encompassing Africa and Eurasia. These humans are represented by a number of specimens that are included within the single, polymorphic, and widespread species H. heidelbergensis. It is suggested that, in the course of the Middle Pleistocene, this species diversified in a number of incipient species -or subspecies- geographically and phenotypically distinct from one another. The case-study furnished by the calvarium found near Ceprano, in Italy, is of great interest in this regard, since it displays the least derived morphology seen among the hypodigm of H. heidelbergensis, and may represent better than other specimens the ancestral morphotype (i.e., the stem subspecies) of this taxon.

Homo sapiens in the Americas. Overview of the earliest human expansion in the New World

Although it is widely recognised that America was the last continent to be populated by our species, researchers' views on various aspects of this process (e.g. the period in which it occurred, the area from which the colonizing populations came, the number of dispersal waves and the routes taken by these migrations) differ significantly. In this paper, we review both classical data and more recent findings from various research fields - including geology, paleoecology, archaeology, skeletal biology, and genetics - that may shed light on the dynamics of the colonization of the American continent, according to a critical reappraisal of the various hypotheses and models that have been advanced over time to explain this process.

The Vindija Neanderthal scapular glenoid fossa: comparative shape analysis suggests evo-devo changes among Neanderthals

Although the shape of the scapular glenoid fossa (SGF) may be influenced by epigenetic and developmental factors, there appears to be strong genetic control over its overall form, such that variation within and between hominin taxa in SGF shape may contain information about their evolutionary histories. Here we present the results of a geometric morphometric study of the SGF of the Neanderthal Vi-209 from Vindjia Cave (Croatia), relative to samples of Plio-Pleistocene, later Pleistocene, and recent hominins. Variation in overall SGF shape follows a chronological trend from the plesiomorphic condition seen in Australopithecus to modern humans, with pre-modern species of the genus Homo exhibiting intermediate morphologies. Change in body size across this temporal series is not linearly directional, which argues against static allometry as an explanation. However, life history and developmental rates change directionally across the series, suggesting an ontogenetic effect on the observed changes in shape (ontogenetic allometry). Within this framework, the morphospace occupied by the Neanderthals exhibits a discontinuous distribution. The Vindija SGF and those of the later Near Eastern Neanderthals (Kebara and Shanidar) approach the modern condition and are somewhat segregated from both northwestern European (Neandertal and La Ferrassie) and early Mediterranean Neanderthals (Krapina and Tabun). Although more than one scenario may account for the pattern seen in the Neanderthals, the data is consistent with palaeogenetic evidence suggesting low levels of gene flow between Neanderthals and modern humans in the Near East after ca. 120-100 ka (thousands of years ago) (with subsequent introgression of modern human alleles into eastern and central Europe). Thus, in keeping with previous analyses that document some modern human features in the Vindija Neanderthals, the Vindija G(3) sample should not be seen as representative of 'classic'--that is, unadmixed, pre-contact--Neanderthal morphology.