Capturing the cervical spine shape: Angular measurements versus geometric morphometric methods.

The cervical spine manifests a wide shape variation. However, the traditional methods to evaluate the cervical spine curve were never tested against its actual shape. The study's main aim was to determine whether the shape classification of the cervical spine, based on traditional angular measurements, coincides with each other and with the shape captured by the 2D landmark-based geometric morphometric method. The study's second aim was to reveal the associations between the cervical spine shape and the demographic parameters, the head's position, and the spine's sagittal balance. CT scans of the cervical spine of 163 individuals were evaluated to achieve these goals. The shape was assessed by measuring the C2-C7 Cobb angle (CA), the C2-C7 posterior tangent angle (PTA), the curvedness of the arch, and by a 2D landmark-based geometric morphometric method. The position of the head and the sagittal balance of the spine were evaluated by measuring the foramen magnum-C2 Cobb angle (FMCA) and the T1 slope angle (T1SA), respectively. Based on the size of the angle measured, each individual was classified into one of the three cervical 'shape groups' (lordotic, straight, and kyphotic). We found that cervical lordosis was the dominant shape regardless of the measuring methods utilized (46.6%-54.6%), followed by straight neck (28.2%-30.1%), and kyphosis (15.3%-25.2%); however, about a third of the 163 individuals were classified into a different shape group using the CA and PTA methods. The cervical spine angle was sex-independent and age-dependent. The T1SA was significantly correlated with CA and PTA (r = 0.640 and r = 0.585, respectively; p < 0.001). In conclusion, the cervical spine shape evaluation is method-dependent and varies with age.

A new method for sex estimation based on femoral cross-sectional geometry measurements and its validation using recent and ancient populations.

Estimating sex is a fundamental task in biological and forensic anthropology. This study aimed to develop new methods for sex estimation based on femoral cross-sectional geometry (CSG) variables and to test their applicability in recent and ancient assemblages. The sample was divided into a study group (living individuals, N = 124) for creating sex prediction equations and two test groups: living individuals (N = 31) and prehistoric individuals (N = 34). The prehistoric sample was divided into three subgroups according to subsistence strategy (hunter-gatherers, early farmers that also hunted, and farmers and herders). Femoral CSG variables (size, strength, and shape) were measured from CT images using dedicated software. Discriminant functions for sex estimation were calculated for various bone completeness scenarios and validated using the test groups. Size and strength parameters were sexually dimorphic, while shape was not. Discriminant functions for sex estimation produced success rates in the living sample between 83.9 and 93.5%; the distal shaft yielded the highest results. Success rates were lower among the prehistoric test sample, with better results (83.3%) for the mid-Holocene population (farmers and herders) than for earlier groups (e.g., hunter-gatherers; < 60%). These results were compared with those obtained using other methods for sex estimation based on various skeletal elements. This study provides new, reliable, and simple methods with high success rates for sex estimation based on femoral CSG variables obtained automatically from CT images. Discriminant functions were created for various conditions of femoral completeness. However, these functions should be used carefully in past populations from different settings.

Evolutionary roots of the risk of hip fracture in humans.

The transition to bipedal locomotion was a fundamental milestone in human evolution. Consequently, the human skeleton underwent substantial morphological adaptations. These adaptations are responsible for many of today's common physical impairments, including hip fractures. This study aims to reveal the morphological changes in the proximal femur, which increase the risk of intracapsular hip fractures in present-day populations. Our sample includes chimpanzees, early hominins, early Homo Neanderthals, as well as prehistoric and recent humans. Using Geometric Morphometric methods, we demonstrate differences in the proximal femur shape between hominids and populations that practiced different lifestyles. We show that the proximal femur morphology is a risk factor for intracapsular hip fracture independent of osteoporosis. Changes in the proximal femur, such as the shortening of the femoral neck and an increased anterolateral expansion of the greater trochanter, are associated with an increased risk for intracapsular hip fractures. We conclude that intracapsular hip fractures are a trade-off for efficient bipedal walking in humans, and their risk is exacerbated by reduced physical activity.

The Hidden Secrets of the Dental Calculus: Calibration of a Mass Spectrometry Protocol for Dental Calculus Protein Analysis.

Dental calculus is a solid deposit that forms and accumulates on the tooth surface, entrapping oral microorganisms, biomolecules, and other micro-debris found in the oral cavity. A mass spectrometry analysis of its protein content opens a vista into the subject's diet, oral flora, and even some aspects of health, thus providing new insight and expanding our knowledge of archaic cultures. Multiple experimental protocols have been proposed for the optimal extraction of proteins from dental calculus. Herein, we compared various experimental conditions in order to calibrate and validate a protocol for protein extraction. Our results show that a high concentration of acetic acid followed by mechanical crushing and sonication provided the highest protein yield, while acetone precipitation enabled the identification of more distinct proteins. We validated this protocol using archeological samples, identifying human and microbial proteins in specimens from the eighth and seventeenth centuries (approximately 250-1300 years ago). These findings demonstrate that the developed protocol is useful for studying excavated archaeological samples and that it might be utilized to explore the biohistory, dietary habits, and microbiome of archaic populations.

Frontal sinuses and human evolution.

The frontal sinuses are cavities inside the frontal bone located at the junction between the face and the cranial vault and close to the brain. Despite a long history of study, understanding of their origin and variation through evolution is limited. This work compares most hominin species' holotypes and other key individuals with extant hominids. It provides a unique and valuable perspective of the variation in sinuses position, shape, and dimensions based on a simple and reproducible methodology. We also observed a covariation between the size and shape of the sinuses and the underlying frontal lobes in hominin species from at least the appearance of Homo erectus. Our results additionally undermine hypotheses stating that hominin frontal sinuses were directly affected by biomechanical constraints resulting from either chewing or adaptation to climate. Last, we demonstrate their substantial potential for discussions of the evolutionary relationships between hominin species.

Response to Comment on "A Middle Pleistocene Homo from Nesher Ramla, Israel".

Marom and Rak claim, on the basis of a few mandibular features, that the Nesher Ramla (NR) Homo is a Neanderthal. Their comments lack substance and contribute little to the debate surrounding the evolution of Middle Pleistocene Homo. Limitations and preconceptions in their study prevented them from achieving resolution beyond a dichotomous interpretation of the NR as either a Neanderthal or a modern human.

Unique foot posture in Neanderthals reflects their body mass and high mechanical stress.

Neanderthal foot bone proportions and morphology are mostly indistinguishable from those of Homo sapiens, with the exception of several distinct Neanderthal features in the talus. The biomechanical implications of these distinct talar features remain contentious, fueling debate around the adaptive meaning of this distinctiveness. With the aim of clarifying this controversy, we test phylogenetic and behavioral factors as possible contributors, comparing tali of 10 Neanderthals and 81 H. sapiens (Upper Paleolithic and Holocene hunter-gatherers, agriculturalists, and postindustrial group) along with the Clark Howell talus (Omo, Ethiopia). Variation in external talar structures was assessed through geometric morphometric methods, while bone volume fraction and degree of anisotropy were quantified in a subsample (n = 45). Finally, covariation between point clouds of site-specific trabecular variables and surface landmark coordinates was assessed. Our results show that although Neanderthal talar external and internal morphologies were distinct from those of H. sapiens groups, shape did not significantly covary with either bone volume fraction or degree of anisotropy, suggesting limited covariation between external and internal talar structures. Neanderthal external talar morphology reflects ancestral retentions, along with various adaptations to high levels of mobility correlated to their presumably unshod hunter-gatherer lifestyle. This pairs with their high site-specific trabecular bone volume fraction and anisotropy, suggesting intense and consistently oriented locomotor loading, respectively. Relative to H.sapiens, Neanderthals exhibit differences in the talocrural joint that are potentially attributable to cultural and locomotor behavior dissimilarity, a talonavicular joint that mixes ancestral and functional traits, and a derived subtalar joint that suggests a predisposition for a pronated foot during stance phase. Overall, Neanderthal talar variation is attributable to mobility strategy and phylogenesis, while H. sapiens talar variation results from the same factors plus footwear. Our results suggest that greater Neanderthal body mass and/or higher mechanical stress uniquely led to their habitually pronated foot posture.

Three-Dimensional Surface Texture Analysis of Fluoride's Effect on Enamel Erosion.

Enamel erosion has become a common clinical finding that often impairs dental esthetics and function. In the current study, we aimed to implement the three-dimensional surface texture analysis (3DST) method to explore the protective effect of fluoride on surface texture prior to erosive conditions. For each of the 50 teeth used in this study, the polished buccal enamel surface was divided into three separate areas: the first area was untouched polished enamel, the two other surfaces were immersed in 0.3% citric acid for 30 s. One was treated with high-concentration (19,000 ppm) sodium fluoride (NaF) solution prior to acid attack, and the other had no treatment prior to acid exposure. Enamel surface texture and step height measurements were obtained using a high-resolution disk scanning confocal microscope, and SEM images were also acquired. Surfaces treated with fluoride showed fewer variations in 3-D surface texture parameters than the eroded surface compared to the control group (p = 0.001). This was in accordance with the SEM descriptive images. The findings indicate that pre-fluoridated enamel areas were less affected by the acid and showed similar features to the untouched enamel. Moreover, a protective effect of the fluoride treatment against irreversible enamel damage was noted as the surface loss (step-height) was significantly reduced (p = 0.03). The study showed that 3DST analysis is a valuable methodology for detecting and quantifying subtle differences between the surfaces. When exploring the combination of all surface texture parameters, it was revealed that the pre-fluoridated eroded enamel surfaces showed considerable similarity to the untouched enamel.

Are chin and symphysis morphology facial type-dependent? A computed tomography-based study.

INTRODUCTION: The chin is a major determinant of the facial profile; hence, it plays a major role in orthodontics and orthognathic surgery. It is thus essential to follow and better understand its expression in different facial types. The major objectives of the current study were to characterize morphometrically the chin and symphysis and reveal their association with different facial types. METHODS: Computed tomography scans of the head and neck of 311 adults (163 males, 148 females; age range, 18-95 years) were classified into 3 facial types: short, average, and long. Height, width, projection, inclination, thickness, and area were measured on the chin and symphysis. RESULTS: The majority of the population (70%) manifested an average facial type; the other 30% were almost equally distributed between short and long facial types. The long facial type was more common among females and the short facial type among males. Chin projection, area, and size were significantly greater in short-faced patients. Chin width in males was similar for all facial types, whereas, in females, chin width was the widest in the short facial type and the narrowest in the long facial type. Symphysis height was significantly greater in long-faced patients in both sexes. The mandibular incisors' inclination relative to the mandibular plane was not significantly associated with the chin or symphysis morphology. CONCLUSIONS: Chin and symphysis morphology is facial type-dependent. Orthodontists and maxillofacial surgeons should be aware of the complex relationship between facial types and chin/symphysis size and shape when planning treatment.

The dental remains from the Early Upper Paleolithic of Manot Cave, Israel.

This study presents the dental remains discovered at Manot Cave (MC), Western Galilee, Israel. The cave contains evidence for human occupation during the Early Upper Paleolithic period (46-33 ka) mainly of Early Ahmarian (∼46-42 ka) and Levantine Aurignacian (∼38-34 ka) cultural levels. Six teeth (three deciduous and three permanent) were found at the site, of which four could be thoroughly analyzed. The morphology of the teeth was qualitatively described and analyzed using traditional and geometric morphometric methods. A large comparative sample was used in order to assess the morphological affiliation of the Manot specimens with other Homo groups. The results provided equivocal signals: the upper first premolar (MC-9 P3) is probably modern human; the upper deciduous second molar (MC-10 dm2) and the upper second permanent molar (MC-8 M2) might be modern humans; the lower second deciduous molar (MC-7 dm2) might be Neanderthal. Owing to the small sample size and the almost total lack of distinctive characteristics, our outcome could not supply conclusive evidence to address the question of whether Manot Aurignacian population came from Europe or descended from the local Ahmarian population.

Early Upper Paleolithic human foot bones from Manot Cave, Israel.

The transition from the Middle Paleolithic to the Upper Paleolithic in the Levant represents a major event in human prehistory with regards to the dispersal of modern human populations. Unfortunately, the scarcity of human remains from this period has hampered our ability to study the anatomy of Upper Paleolithic populations. This study describes and examines pedal bones recovered from the Early Upper Paleolithic period at Manot Cave, Israel, from 2014 to 2017. The Manot Cave foot bones include a partial, left foot skeleton comprising a talus, a calcaneus, a cuboid, a first metatarsal, a second metatarsal, a fifth metatarsal, and a hallucal sesamoid. All these remains were found in the same archaeological unit of the cave and belong to a young adult. Shape and size comparisons with Neanderthals, Anatomically Modern Human and modern human foot bones indicate a modern human morphology. In some characteristics, however, the Manot Cave foot bones display a Neanderthal-like pattern. Notably, the Manot Cave foot is remarkable in its overall gracility. A healed traumatic injury in the second metatarsal (Lisfranc's fracture) is most likely due to a remote impact to the dorsum of the foot. This injury, its subsequent debility, and the individual's apparent recovery suggest that the members of the Manot Cave community had a supportive environment, one with mutual responsibilities among the members.

The endocast of the late Middle Paleolithic Manot 1 specimen, Western Galilee, Israel.

Studying endocasts has long allowed anthropologists to examine changes in the external topography and the overall size of the brain throughout the evolutionary history of hominins. The nearly complete calvaria of Manot 1 presents an opportunity to gain insights into the external brain morphology, vascular system, and dimensions of the brain of this late Middle Paleolithic hominin. Detailed size and shape analyses of the Manot 1 endocast indicate a modern Homo sapiens anatomy, despite the presence of some primitive features of the calvaria. Traits considered to be derived endocranial features for H. sapiens are present in Manot 1, including an elongated parietal sagittal chord with an elevated superior part of the hemisphere, a widened posterior part of the frontal lobes, a considerable development of the parietal reliefs such as the supramarginal lobules, and a slight posterior projection of the occipital lobes. These findings, together with data presented in previous studies, rule out the possibility of a direct Neanderthal ancestry for the Manot 1 hominin and instead confirm its affiliation with H. sapiens. The Manot 1 calvaria is more similar to that of later Upper Paleolithic H. sapiens than it is to the earlier Levantine populations of Skhul and Qafzeh. The late Middle Paleolithic date of Manot 1 provides an opportunity to analyze the recent developments in human cerebral morphology and organization.

Age estimation of fragmented human dental remains by secondary dentin virtual analysis.

Unlike bones, teeth are remarkably resilient and can withstand severe trauma, making age assessment based on the dentition essential for forensic analysis. Modern techniques for age estimation focus on pulp-chamber volume measurements using radiographs and computerized tomography (CT); however, these are applicable only for complete teeth (i.e., with intact crown and root). In the current study, we developed a new approach using high-resolution micro-computerized tomography (µCT) to visualize the secondary dentin (SD), an inner layer surrounding the pulp which accumulates with age, thus facilitating age estimation of fragmented and broken teeth.The growth pattern of the SD with age was analyzed for 77 lower premolars from two anthropological collections. A comparison of SD virtual segmentation and histological measurement was highly correlative (ICC = 0.95). SD was measured per volume (mm3) of a 1 mm thick slice directly below the cemento-enamel junction. Regression analysis using SD measurements increased the success rates of age estimation (82%) compared with the "gold-standard" pulp/dentin method (54%) in the range of ± 10 years. The accuracy of age estimation based on SD analysis was improved to a range of 7-8 years.The SD method thus allows age estimation with greater prediction rates and better accuracy based on only a small fragment of a tooth in a non-invasive manner. This novel methodology is easy to use, accessible, and bears implications in various fields such as forensic sciences and anthropological research.

Variation in Chin and Mandibular Symphysis Size and Shape in Males and Females: A CT-Based Study.

The chin is a unique anatomical landmark of modern humans. Its size and shape play an important role from the esthetic perspective. However, disagreement exists in the dental and anthropological literature regarding the sex differences in chin and symphysis morphometrics. The "sexual selection" theory is presented as a possible reason for chin formation in our species; however, many other contradictory theories also exist. This study's aims were therefore to determine how chin and symphysis size and shape vary with sex, and to discuss "sexual selection" theory as a reason for its formation. Head and neck computed tomography (CT) scans of 419 adults were utilized to measure chin and symphysis sizes and shapes. The chin and symphysis measures were compared between the sexes using an independent-samples t-test, a Mann-Whitney test, and the F-statistic. The chin width was significantly greater in males than in females (p < 0.001), whereas the chin height, area, and size index were significantly greater in females (p < 0.001). Symphysis measures did not differ significantly between the sexes. Size accounted for 2-14% of the chin variance and between 24-33% of the symphysis variance. Overall, the chin was found to be a more heterogeneous anatomical structure than the symphysis, as well as more sexually dimorphic.

New methods for sex estimation using sternum and rib morphology.

Sex estimation of skeletal remains is of great importance in the fields of physical and forensic anthropology. Since skeletons are often incomplete, it is essential to estimate sex from as many skeletal remains as possible. The aim of this study was to establish new methods for estimating sex using the morphology of the sternum and the fifth to ninth ribs. We considered two conditions of skeletal preservation: All skeletal elements measured are available, or only a single element is available. Traditional or virtual measurements were carried out on three samples: (1) A skeletal sample from the Hamann-Todd Human osteological collection, Cleveland Museum of Natural History, USA (N = 413), was used to create prediction equations for sex estimation. (2) A recent, CT-based sample from Israel (N = 33) was used to cross-validate the accuracy of the prediction equations. (3) A skeletal sample from the Anthropological Collection at Tel Aviv University (N = 15) was used to test the validity of the virtual measurements. Reliability and validity analyses were carried out via intraclass correlation coefficient analysis. Prediction equations for sex were created using logistic regression. The measurements were found to be highly reliable and valid. Success rates for sex estimation were high (> 80%) and correspond well between the skeletal and recent samples, especially for the left sixth, left eigth, and left ninth ribs. To conclude, measurements of the sternum and ribs are valuable for estimating sex and can be carried out using either traditional or virtual tools. Of all the skeletal elements examined in this study, the sternum, left sixth, left eighth, and left ninth ribs were found to be the most reliable skeletal elements for estimating the sex of an individual.

Suggested Case of Langerhans Cell Histiocytosis in a Cretaceous dinosaur.

Susceptibility to diseases is common to humans and dinosaurs. Since much of the biological history of every living creature is shaped by its diseases, recognizing them in fossilized bone can furnish us with important information on dinosaurs' physiology and anatomy, as well as on their daily activities and surrounding environment. In the present study, we examined the vertebrae of two humans from skeletal collections with Langerhans Cell Histiocytosis (LCH), a benign osteolytic tumor-like disorder involving mainly the skeleton; they were diagnosed in life, along with two hadrosaur vertebrae with an apparent lesion. Macroscopic and microscopic analyses of the hadrosaur vertebrae were compared to human LCH and to other pathologies observed via an extensive pathological survey of a human skeletal collection, as well as a three-dimensional reconstruction of the lesion and its associated blood vessels from a µCT scan. The hadrosaur pathology findings were indistinguishable from those of humans with LCH, supporting that diagnosis. This report suggests that hadrosaurids had suffered from larger variety of pathologies than previously reported. Furthermore, it seems that LCH may be independent of phylogeny.

Changes in human mandibular shape during the Terminal Pleistocene-Holocene Levant.

The transition to food production, exploitation of 'secondary' products (e.g., milk), and advances in cookware technology have affected all aspects of human life. The aim of the present study was to follow changes in mandibular form and shape throughout the terminal Pleistocene-Holocene Levant. The hemimandibles of four populations were included in this study: Natufian hunter-gatherers (n = 10), Pre-pottery Neolithic early farmers (n = 6), Chalcolithic farmers (n = 9), Roman-Byzantine (n = 16), and modern (n = 63) populations. A surface mesh of each mandible was reconstructed from CT or surface scans. Changes in mandibular form and shape were studied using the Procrustes-based geometric morphometrics method. Univariate and multivariate analyses were carried out to examine differences in size and shape between the studied populations. Our results reveal considerable temporal changes in mandibular shape throughout the Holocene Levant, mainly between the pre-agricultural population (the Natufian) and the succeeding ones, and between the post-industrial (the Modern) and the pre-industrial populations. A tendency for a reduction in mandibular size was identified between the pre-agricultural population and the farmers. Most regions of the mandible underwent shape changes. In conclusion, substantial changes in mandibular shape occurred throughout the Holocene Levant, especially following the agricultural revolution. These changes can be explained by the "masticatory-functional hypothesis".

Late Pleistocene human genome suggests a local origin for the first farmers of central Anatolia.

Anatolia was home to some of the earliest farming communities. It has been long debated whether a migration of farming groups introduced agriculture to central Anatolia. Here, we report the first genome-wide data from a 15,000-year-old Anatolian hunter-gatherer and from seven Anatolian and Levantine early farmers. We find high genetic continuity (~80-90%) between the hunter-gatherers and early farmers of Anatolia and detect two distinct incoming ancestries: an early Iranian/Caucasus related one and a later one linked to the ancient Levant. Finally, we observe a genetic link between southern Europe and the Near East predating 15,000 years ago. Our results suggest a limited role of human migration in the emergence of agriculture in central Anatolia.

Publisher Correction: Ancient DNA from Chalcolithic Israel reveals the role of population mixture in cultural transformation.

In the original version of this Article, references in the format 'First author et al.' were inappropriately deleted. These errors have been corrected in the PDF and HTML versions of the Article.

Ancient DNA from Chalcolithic Israel reveals the role of population mixture in cultural transformation.

The material culture of the Late Chalcolithic period in the southern Levant (4500-3900/3800 BCE) is qualitatively distinct from previous and subsequent periods. Here, to test the hypothesis that the advent and decline of this culture was influenced by movements of people, we generated genome-wide ancient DNA from 22 individuals from Peqi'in Cave, Israel. These individuals were part of a homogeneous population that can be modeled as deriving ~57% of its ancestry from groups related to those of the local Levant Neolithic, ~17% from groups related to those of the Iran Chalcolithic, and ~26% from groups related to those of the Anatolian Neolithic. The Peqi'in population also appears to have contributed differently to later Bronze Age groups, one of which we show cannot plausibly have descended from the same population as that of Peqi'in Cave. These results provide an example of how population movements propelled cultural changes in the deep past.