Validation and reliability of the sex estimation of the human os coxae using freely available DSP2 software for bioarchaeology and forensic anthropology

What we see is what we touch? Sex estimation on the skull in virtual anthropology

BACKGROUND

The increased use of virtual bone images in forensic anthropology requires a comprehensive study on the observational errors between dry bones and CT reconstructions. Here, we focus on the consistency of nonmetric sex estimation traits on the human skull.

MATERIALS AND METHODS

We scored nine nonmetric traits on dry crania and mandibles (n = 223) of archaeological origin and their CT reconstructions. Additionally, we 3D surface scanned a subsample (n = 50) and repeated our observations. Due to the intricate anatomy of the mental eminence, we split it into two separate traits: the bilateral mental tubercles and the midsagittal mental protuberance. We provide illustrations and descriptions for both these traits.

RESULTS

We obtained supreme consistency values between the CT and 3D surface modalities. The most consistent cranial traits were the glabella and the supraorbital margin, followed by the nuchal crest, zygomatic extension, mental tubercles, mental protuberance, mental eminence, mastoid process and ramus flexure, in descending order. The mental tubercles show higher consistency scores than the mental eminence and the mental protuberance.

DISCUSSION

The increased interchangeability of the virtual modalities with each other as compared to the dry bone modality could be due to the lack of tactility on both the CT and surface scans. Moreover, tactility appears less essential with experience than a precise trait description. Future studies could revolve around the most consistent cranial traits, combining them with pelvic traits from a previous study, to test for accuracy.

Classification performance of the Sella-Tunis et al. (2017) sex estimation method in Czech population: different posterior probability threshold approaches

In this study we tested classification performance of a sex estimation method from the mandible originally developed by Sella-Tunis et al. (2017) on a heterogeneous Israeli population. Mandibular linear dimensions were measured on 60 CT scans derived from the Czech living population. Classification performance of Israeli discriminant functions (DFs-IL) was analyzed in comparison with calculated Czech discriminant functions (DFs-CZ) while different posterior probability thresholds (currently discussed in the forensic literature) were employed. Our results comprehensively illustrate sensitivity of different discriminant functions to population differences in body size and degree of sexual dimorphism. We demonstrate that the error rate may be biased when presented per posterior probability threshold. DF-IL 1 showed least sensitivity to population origin and fulfilled criteria of sufficient classification performance when applied on the Czech sample with a minimum posterior probability threshold of 0.88 reaching overall accuracy ≥ 95%, zero sex bias, and 80% of classified individuals. The last parameter was higher in DF-CZ 1 which was the main difference between those two DFs suggesting relatively low dependance on population origin. As the use of population-specific methods is often prevented by complicated assessment of population origin, DF-IL 1 is a candidate for a sufficiently robust method that could be reliably applied outside the reference sample, and thus, its classification performance deserves further testing on more population samples.

Automatic variable extraction from 3D coxal bone models for sex estimation using the DSP2 method

Thanks to technical progress and the availability of virtual data, sex estimation methods as part of a biological profile are undergoing an inevitable evolution. Further reductions in subjectivity, but potentially also in measurement errors, can be brought by approaches that automate the extraction of variables. Such automatization also significantly accelerates and facilitates the specialist's work. The aim of this study is (1) to apply a previously proposed algorithm (Kuchař et al. 2021) to automatically extract 10 variables used for the DSP2 sex estimation method, and (2) to test the robustness of the new automatic approach in a current heterogeneous population. For the first aim, we used a sample of 240 3D scans of pelvic bones from the same individuals, which were measured manually for the DSP database. For the second aim a sample of 108 pelvic bones from the New Mexico Decedent Image Database was used. The results showed high agreement between automatic and manual measurements with rTEM below 5% for all dimensions except two. The accuracy of final sex estimates based on all 10 variables was excellent (error rate 0.3%). However, we observed a higher number of undetermined individuals in the Portuguese sample (25% of males) and the New Mexican sample (36.5% of females). In conclusion, the procedure for automatic dimension extraction was successfully applied both to a different type of data and to a heterogeneous population.

Well supplied in life, set aside in death: A multi-isotope study of Justinian plague victims from Saint-Doulchard (France, 7th-8th centuries AD)

OBJECTIVES

Justinian plague and its subsequent outbreaks were major events influencing Early Medieval Europe. One of the affected communities was the population of Saint-Doulchard in France, where plague victim burials were concentrated in a cemetery enclosure ditch. This study aimed to obtain more information about their life-histories using the tools of isotope analysis.

MATERIALS AND METHODS

Dietary analysis using carbon and nitrogen isotopes was conducted on 97 individuals buried at Le Pressoir in Saint-Doulchard, with 36 of those originating from the enclosure ditch. This sample set includes all individuals analyzed for plague DNA in a previous study. Mobility analysis using strontium isotope analysis supplements the dietary study, with 47 analyzed humans. The results are supported by a reference sample set of 31 animal specimens for dietary analysis and 9 for mobility analysis.

RESULTS

The dietary analysis results showed significantly different dietary behavior in individuals from the ditch burials, with better access to higher quality foods richer in animal protein. 87Sr/86Sr ratios are similar for both studied groups and indicate a shared or similar area of origin.

DISCUSSION

The results suggest that the ditch burials contain an urban population from the nearby city of Bourges, which overall had a better diet than the rural population from Saint-Doulchard. It is implied that city's population might have been subjected to high mortality rates during the plague outbreak(s), which led to their interment in nearby rural cemeteries.

Prioritizing a high posterior probability threshold leading to low error rate over high classification accuracy: the validity of MorphoPASSE software for cranial morphological sex estimation in a contemporary population

An increasing number of software tools can be used in forensic anthropology to estimate a biological profile, but further studies in other populations are required for more robust validation. The present study aimed to evaluate the validity of MorphoPASSE software for sex estimation from sexually dimorphic cranial traits recorded on 3D CT models (n = 180) from three populations samples (Czech, French, and Egyptian). Two independent observers performed scoring of 4 cranial traits (2 of them bilateral) in each population sample of 30 males and 30 females. The accuracy of sex estimation using traditional posterior probability threshold (pp = 0.5) ranged from 85.6% to 88.3% and overall classification error from 14.4% to 11.7% for both observers, and corresponds to the previously published values of the method. The MorphoPASSE method is also affected by the subjectivity of the observers, as both observers show agreement in sex assignment in 83.9% of cases, regardless of the accuracy of the estimates. Applying a higher posterior probability threshold (pp 0.95) provided classification accuracy of 97.9% and 93.3% of individuals (for observer A and B respectively), minimizing the risk of error to 2.1% and 6.7%, respectively. However, sex estimation can only be applied to 54% and 66% of individuals, respectively. Our results demonstrate the validity of the MorphoPASSE software for cranial sex estimation outside the reference population. However, the achieved classification success is accompanied by a high risk of errors, the reduction of which is only possible by increasing the posterior probability threshold.

Ancient Egyptian scribes and specific skeletal occupational risk markers (Abusir, Old Kingdom)

Men with writing proficiency enjoyed a privileged position in ancient Egyptian society in the third millennium BC. Research focusing on these officials of elevated social status ("scribes") usually concentrates on their titles, scribal statues, iconography, etc., but the individuals themselves, and their skeletal remains, have been neglected. The aim of this study is to reveal whether repetitive tasks and maintained postures related to scribal activity can manifest in skeletal changes and identify possible occupational risk factors. A total of 1767 items including entheseal changes, non-metric traits, and degenerative changes were recorded from the human remains of 69 adult males of well-defined social status categories from the necropolis at Abusir (2700-2180 BC). Statistically significant differences between the scribes and the reference group attested a higher incidence of changes in scribes and manifested themselves especially in the occurrence of osteoarthritis of the joints. Our research reveals that remaining in a cross-legged sitting or kneeling position for extended periods, and the repetitive tasks related to writing and the adjusting of the rush pens during scribal activity, caused the extreme overloading of the jaw, neck and shoulder regions.

Metric analysis of the patella for sex estimation in a Portuguese sample

The biological profile estimation is the first step toward positive identification. However, it is not always possible to access a complete and well-preserved skeleton due to postmortem damage and taphonomic changes. As such, there is a need to develop new alternatives to analyze different bones of the human skeleton. The present study aims to analyze the patellar osteometry, with attention to its degree of sexual dimorphism, to establish a simple method for estimating sex in Portuguese adults. Six measurements were taken from 222 patella pairs, including 117 females and 105 males from the XXI Century Identified Skeleton Collection of the University of Coimbra. Subsequently, this method was validated in a different sample of 50 individuals equally representing both sexes. Maximum height stands out with a 77.0% of correct sex estimation, reaching 98.0% when applied to the new sample. The linear discriminant function analysis containing all the six variables showed the best results, with 80.2% of correct classification after cross-validation and 96.0% when applied to the independent sample.

How geographical origin and dietary habits interact with the shape of cortical mandibular sections? A geometric morphometrics study in an archaeological context

OBJECTIVE

Mandibular shape is strongly influenced by biomechanics, particularly during dietary shifts that often occurred in past populations. The relationship is considered extremely complex as development of the mandible is a multifactorial process. Since cortical bone distribution is purportedly more biomechanically sensitive than external shape, comparison of its distribution in past populations can provide new input to understand this complex relationship. The present study examined the effects of geographical origin and dietary habits on the internal anatomy of the mandibular corpus and symphysis.

DESIGN

A morphometric analysis was conducted on 72 mandibles from different populations, sampled by their geographical origin and subsistence strategies. Procrustes ANOVAs were performed to test the impact of section-plane location, geographical origin, and dietary habits on the groups' shapes.

RESULTS

The specimens' geographical origin and dietary habits had a significant effect on the shapes of the sections (Generalized Goodall F-test, F = 3.2745, df = 6, 304: p < 0.001 and F = 3.7007, df = 4, 306: p < 0.001).

CONCLUSION

Geographical origin and dietary habits influenced the shape of the mandibular sections in our sample. These relationships become more complex when analysed in isolated sections. Indeed, this study revealed that symphysis sections could be predominantly influenced by individual variables, whereas intermediate sections of the corpus could be predominantly influenced by populational variables. Future studies could focus on specific sections to better identify the specific "rules of dependence" in each cross-section.

Female biased adult sex ratio in the Bronze Age cemetery of Shahr-i Sokhta (Iran) as an indicator of long distance trade and matrilocality

OBJECTIVES

This paper starts from the unusual observation of the overrepresentation of females among adults in the cemetery of Bronze Age Shahr-i Sokhta (Seistan, Iran) and explores the post marital residence pattern. By integrating taphonomical (skeletal preservation), anthropological (sex ratio [SR], sexual dimorphism, stress indicators, age at death), archeological (long distance trade indicators, habitation floor area, social role of women), and ancient DNA (heterozygosity levels in X chromosomes) data we test the hypothesis of post marital matrilocality in the site.

METHODS

We computed the SR (pelvis-based sex determination) in a random unpublished adult sample from the cemetery of Shahr-i Sokhta and in two samples previously published by other authors. We used comparative data on SR from: a large Supra Regional multi-chronological sample of sites, n = 47, with 8808 adult sexed individuals, from Southern Europe, Egypt, Middle East, Southern Russia; a Regional Bronze Age sample of sites (n = 10) from Bactria Margiana and Indus Valley with 1324 adult sexed individuals. We estimated the heterozygosity levels in X chromosomes compared with the rest of the autosomes on the assumption that in a matrilocal society females should show lower variability than men.

RESULTS

Adult SR in a sample (n = 549) from Shahr-i Sokhta is 70.5, the overrepresentation of females is shared with Regional Bronze Age sites from Bactria Margiana (SR = 72.09) and Indus Valley (SR = 67.54). On the contrary, in a larger Supra Regional multi-chronological sample of sites, mean SR ranges between 112.7 (Bronze Age) and 163.1 (Middle Ages). Taphonomical and anthropological indicators do not explain the overrepresentation of female skeletons. Archeological indicators suggest a high social status of women and that the society was devoted to long range trade activities. heterozygosity levels in X chromosomes are in agreement with a matrilocal society.

CONCLUSIONS

Indicators suggest that Bronze Age Shahr-ì Sokhta was a matrilocal society and that long distance trade was an important economic factor producing an overrepresentation of adult female skeletons in the cemetery.

Sex estimation of the adult Neandertal Regourdou 1 (Montignac, France): Implications for sexing human fossil remains

Sex is a biological trait fundamental to the study of hominin fossils. Among the many questions that can be addressed are those related to taxonomy, biological variability, sexual dimorphism, paleoobstetrics, funerary selection, and paleodemography. While new methodologies such as paleogenomics or paleoproteomics can be used to determine sex, they have not been systematically applied to Pleistocene human remains due to their destructive nature. Therefore, we estimated sex from the coxal bone of the newly discovered pelvic remains of the Regourdou 1 Neandertal (Southwest France, MIS 5) based on morphological and metric data employing two methods that have been recently revised and shown to be reliable in multiple studies. Both methods calculate posterior probabilities of the estimate. The right coxal bone of Regourdou 1 was partially reconstructed providing additional traits for sex estimation. These methods were cross validated on 14 sufficiently preserved coxal bones of specimens from the Neandertal lineage. Our results show that the Regourdou 1 individual, whose postcranial skeleton is not robust, is a male, and that previous sex attributions of comparative Neandertal specimens are largely in agreement with those obtained here. Our results encourage additional morphological research of fossil hominins in order to develop a set of methods that are applicable, reliable, and reproducible.

A, Kis L, Király K, Varga S, Marcsik A, Schütz O, Török T, Hunt DR, Tihanyi B. White plague among the "forgotten people" from the Barbaricum of the Carpathian Basin-Cases with tuberculosis from the Sarmatian-period (3rd-4th centuries CE) archaeological site of Hódmezővásárhely-Kenyere-ér, Bereczki-tanya (Hungary)

Tuberculosis (TB) is a bacterial infection that is well-known in the palaeopathological record because it can affect the skeleton and consequently leaves readily identifiable macroscopic alterations. Palaeopathological case studies provide invaluable information about the spatio-temporal distribution of TB in the past. This is true for those archaeological periods and geographical regions from when and where no or very few TB cases have been published until now-as in the Sarmatian period (1st-5th centuries CE) in the Barbaricum of the Carpathian Basin. The aim of our paper is to discuss five newly discovered TB cases (HK199, HK201, HK225, HK253, and HK309) from the Sarmatian-period archaeological site of Hódmezővásárhely-Kenyere-ér, Bereczki-tanya (Csongrád-Csanád county, Hungary). Detailed macromorphological evaluation of the skeletons focused on the detection of bony changes likely associated with different forms of TB. In all five cases, the presence of endocranial alterations (especially TB-specific granular impressions) suggests that these individuals suffered from TB meningitis. Furthermore, the skeletal lesions observed in the spine and both hip joints of HK225 indicate that this juvenile also had multifocal osteoarticular TB. Thanks to the discovery of HK199, HK201, HK225, HK253, and HK309, the number of TB cases known from the Sarmatian-period Carpathian Basin doubled, implying that the disease was likely more frequent in the Barbaricum than previously thought. Without the application of granular impressions, the diagnosis of TB could not have been established in these five cases. Thus, the identification of TB in these individuals highlights the importance of diagnostics development, especially the refinement of diagnostic criteria. Based on the above, the systematic macromorphological (re-)evaluation of osteoarchaeological series from the Sarmatian-period Carpathian Basin would be advantageous to provide a more accurate picture of how TB may have impacted the ancestral human communities of the Barbaricum.

DSP2 for sex determination of miscegenated contemporary hip bones

The bones of the human pelvis are used in sexual diagnosis generating a high level of accuracy for this type of identification. Morphological and/or morphometric methods are used in the identification of sex. Sexual dimorphism may be affected by ethnic differences in the population. One of the methods for determining sex using hip bone is the 'Diagnose Sexuelle Probabiliste (DSP)' or Probabilistic Sexual Diagnosis (DSP) method. The method presents a new version (Probabilistic Sexual Diagnosis v.2-DSP2) more advisable to be used because it has a more up-to-date database. The objective of this study is to investigate the applicability of the DSP2 method in a population in the Northeast region of Brazil. We used 128 hip bones, 50 female and 78 males, aged between 17 and 101 years, belonging to the Laboratory of Human Identification and Forensic Osteology of the University Federal Government of Pernambuco. The research was conducted between 2019 and 2020 and approved by the Research Ethics Committee of the Federal University of Pernambuco no. 43228015.0.0000.5208. The probability equal to or greater than 0.95 was used as the limit for the determination of sex, and the results were compared with the actual sex of each bone. In the Brazilian collection study, it was observed that the percentage of sex estimation provided by the DSP2 tool using all reference samples was 71.09%, and accuracy was 64.06%. In the analysis of the gender estimate, 82.0% and 78% were obtained for females and males, respectively. Regarding accuracy, it was 64.10% and 55.13% for females and males, respectively. In the contemporary osteological collection of the Northeast region of Brazil, which presents immigrant peoples, we obtained a high index of assertiveness in the DSP2 method. The study concluded that the DSP2 method is important for determining the sex of human skeletons in a miscegenated population.

Morphometric evaluation of the orbital region for sex determination in a Saudi Arabian population using 3DCT images

In forensic anthropology, the analysis of variations in the orbitometric features plays a crucial role in identifying the sex of a skull detached from its skeleton. Therefore, it is essential to create population-specific values to maximize the accuracy rate of sex estimation. The objective of this study was to evaluate the orbital region morphometrically for sex determination in a Saudi Arabian population using CT scan images. This study included 456 CT images (228 males and 228 females; age range, 18-58 years). Six orbital measurements and the orbital index of both sides were evaluated to determine sexual dimorphism and laterality using an independent t-test. Sex was estimated using discriminant function analysis. Based on the orbital index, the orbit was classified into megasemes, mesosemes, and microsemes. All the measurements were significantly greater in males than females, but the orbital index showed no significant sexual dimorphism. No significant asymmetry was found in all orbital dimensions. The univariate discriminant function of the orbital measurements showed an accuracy rate between 83.8 and 70%. The multivariate analysis classified the orbital dimensions into male (93%) and female (92.1%) to the highest level of accuracy. In Saudis, the megaseme category was the most prevalent form of orbit. The right orbit height (83.8%), left orbit height (80.7%), right orbit width (79.4%), and left orbit height (79.4%) were the most reliable variables that could be used in sex determination. According to multivariate analysis, the overall accuracy rate for determining sex was 92.1%. While the present study data may not be used alone for sexing a complete skull, there must be various occasions in which this new standard will contribute to determining sex in forensic contexts.

Unbalanced sex-ratio in the Neolithic individuals from the Escoural Cave (Montemor-o-Novo, Portugal) revealed by peptide analysis

The sex profile estimation of pre-historic communities is often complicated by the commingled and scattered nature of skeletal assemblages. Demographic profiles are usually lacking and provide very truncated representations of these populations but proteomic analysis of sex-specific amelogenin peptides in tooth enamel brings new promise to these studies. The main objective was to obtain the sex profile of the human assemblage recovered from the Neolithic cave-necropolis of Escoural (Montemor-o-Novo, southern Portugal) through liquid chromatography-mass spectrometry. The secondary objective was to analyse sex-specific linear enamel hypoplasias (LEH), and to test the reliability of canine odontometric sex estimation. Sex estimation through peptide analysis was carried out in 36 left permanent canines which were macroscopically examined for the presence of LEH. The canine buccolingual diameter was used for odontometric sex estimation. The obtained sex ratio (0.5:1, M:F) is biased to female individuals, probably due to cultural factors since the natural sex ratio of the human population falls between 0.95:1 and 1.02:1 (M:F). A high frequency of LEH was observed, but with no significant sexual differences (p = 0.554). The mean LEH age of onset occurred at 3 years of age, with no significant differences between the sexes (p = 0.116), and was possibly related to the weaning process. Odontometric sex estimation revealed a correct classification of 80%, with a high number of males mistakenly attributed to females. This study is one of the largest samples subjected to peptide analysis, and thus demonstrates its usefulness on the research of commingled and scattered skeletal assemblages.

Measuring pelvises in 3D surface scans and in MDCT generated virtual environment: Considerations for applications in the forensic context

Virtual Anthropology (VA) transposes the traditional methods of physical anthropology to virtual environments using imaging techniques and exploits imaging technologies to devise new methodological protocols. In this research, we investigate whether the measurements used in the Diagnose Sexuelle Probabiliste (DSP) and Ischio-Pubic Index (IPI) differ significantly when 3D models of a bone are generated using 3D surface scans (3DSS) and Multidetector Computed Tomography (MDCT) scans. Thirty pelvises were selected from the SIMON identified skeletal collection. An equal ratio of females to males was sought, as well as a good preservation of the bones. The pelvises were scanned using an MDCT scanner and a 3D surface scanner. The measurements of the DSP and IPI methods on the dry bones (referred to as macroscopic measurements here), and then to the 3D models. The intra- and interobserver, using the Technical Error of Measurement (TEM) and relative Technical Error of Measurement (rTEM) error was assessed, and we aimed to observe if the measurements made on the MDCT and 3DSS generated models were significantly different from those taken on the dry bones. Additionally, the normality of the data was tested (Shapiro-Wilk test) and the differences in measurements was evaluated using parametric (Student t-tests) and non-parametric (Wilcoxon) tests. The TEM and rTEM calculations show high intra and interobserver consistency in general. However, some measurements present insufficient inter- and intraobserver agreement. Student t and Wilcoxon tests indicate potentially significant differences of some measurements between the different environments. The results show that especially in the virtual environment, it is not easy to find the right angle for some of the DSP measurements, However, when comparing the measurement differences between dry and virtual bones, the results show that most of the differences are less than or equal to 2.5 mm. Considering the IPI, the landmarks are already difficult to determine on the dry bone, but they are even more difficult to locate in the virtual environment. Nevertheless, this study shows that quantitative methods may be better suited for application in the virtual environment, but further research using different methods is needed.

How reliable is the application of the sex classifier based on exocranial surface (Musilová et al., 2016) for geographically and temporally distant skull series

Sex estimation is one of the crucial trends in cases of findings of unknown skeletal remains in forensics and bioarchaeology. The changing nature of sexual dimorphism (population specificity, secular trend, other external and internal factors influence) brings challenges to developing new methods; and there are new aims to be independent of these changes such, as the method by Musilová et al. (2016). These methods need to be evaluated on different datasets to determine if they are truly reliable among populations from different places and times, in the case of bioarchaeology. This study assessed the application of the aforementioned method on non-European contemporary and ancient populations to identify the reliability of the method on this separate dataset. The study sample consisted of 96 CT scans of skulls from contemporary Egyptians and 54 3D models of skulls from the Egyptian Old Kingdom Period (2700-2180 BC). The classifier method, previously tested on both Czech and French populations, yielded high accuracies (over 90 %) for sex estimation. For the contemporary Egyptian skull sample, the classifier was able to determine males versus females with an 89.59 % accuracy rate and an AUC value (area under the curve - a measure of the combined specificity and sensitivity of the test) of 0.99; this proves that the classifier is reliable even with a lower degree of accuracy. Conversely, the Old Kingdom Period sample yielded a lower level of accuracy at around 70 % (61.11 %, precisely), although with an AUC value of 0.92, the result is not considered reliable.

What we see is what we touch? Sex estimation on the pelvis in virtual anthropology

BACKGROUND

Computed tomography (CT) scans are a convenient means to study 3D reconstructions of bones. However, errors associated with the different nature of the observation, e.g. visual and tactile (on dry bone) versus visual only (on a screen) have not been thoroughly investigated.

MATERIALS AND METHODS

We quantified the errors between modalities for sex estimation protocols of nonmetric (categorical and ordinal) and metric data, using 200 dry pelves of archaeological origin and the CT reconstructions of the same bones. In addition, we 3D surface scanned a subsample of 39 pelves to compare observations with dry bone and CT data. We did not focus on the sex estimation accuracy but solely on the consistency of the scoring, hence, the interchangeability of the modalities.

RESULTS

Metric data yielded the most consistent results. Among the nonmetric protocols, ordinal data performed better than categorical data. We applied a slightly modified description for the trait with the highest errors and grouped the traits according to consistency and availability in good, intermediate, and poor.

DISCUSSION

The investigated modalities were interchangeable as long as the trait definition was not arbitrary. Dry bone (gold standard) performed well, and CT and 3D surface scans performed better. We recommend researchers test their affinity for using virtual modalities. Future studies could use our consistency analysis and combine the best traits, validating their accuracy on various modalities.

Multivariate assessments of activity-related skeletal changes: Interpreting Bell Beaker specialized male archery and social organization in Central Europe

OBJECTIVES

The Bell Beaker period witnessed the rise of individual inhumations with "wealthy" burial contexts containing archery-related grave goods, leading archaeologists to label the individuals in these tombs as "archers." This study looks to (1) compare the skeletons from male "archer" burials with those from male "non-archer" burials-those not having archery-related grave goods-in order to assess a possible link between burial context and physical activity, and (2) apply a biomechanics profile to evaluate whether the individuals associated with these "archer" burials practiced specialized archer activity.

MATERIALS AND METHODS

The corpus (males only) included 46 "archers" and 40 "non-archers" from Bell Beaker individual inhumations. Osteological data included measurements, scores of entheseal changes, and a diagnosis of certain pathologies. Data analyses involved visual observations, hypothesis tests, dimension reduction, and MANOVA, with approaches aimed at exploring the treatment of data missingness.

RESULTS

Measurement data revealed no differences between the two groups. Evaluations of entheseal changes found that "non-archers" had consistently more instances of bone surface modifications than "archers." Individual assessments of specialized archer occupation identified 11 possible specialized archers.

DISCUSSION

These findings indicate a possible labor differentiation represented through the presence of a probably prestigious "archer" burial context. This suggests a link between grave good presence and labor, but not between a Bell Beaker archery occupation and an "archer" burial context. Data analyses support the application of biomechanics to osteological analyses in order to assess specialized activity on the skeleton.

Leprosy: The age-old companion of humans - Re-evaluation and comparative analysis of Avar-period cases with Hansen's disease from the Danube-Tisza Interfluve, Hungary

In recent years, our knowledge of leprosy in the past has substantially been enriched. Nonetheless, much still remains to be discovered, especially in regions and periods from where no written sources are available. To fill in some research gaps, we provide the comparative analysis of eight Avar-period leprosy cases from the Danube-Tisza Interfluve (Hungary). In every case, to reconstruct the biological consequences of leprosy, the detected bony changes were linked with palaeopathological and modern medical information. To reconstruct the social consequences of being affected by leprosy, conceptualisation of the examined individuals' treatment in death was conducted. In every case, the disease resulted in deformation and disfigurement of the involved anatomical areas (rhinomaxillary region, feet, and/or hands) with difficulties in conducting certain physical activities. These would have been disadvantageous for the examined individuals and limited or changed their possibilities to participate in social situations. The most severe cases would have required continuous support from others to survive. Our findings indicate that, despite their very visible disease and associated debility, the examined communities did not segregate leprosy sufferers but provided and cared for them, and maintained a strong enough social network that made their survival possible even after becoming incapable of self-sufficiency.

The casts of Pompeii: Post-depositional methodological insights

The casts of Pompeii bear witness to the people who died during the Vesuvius 79 AD eruption. However, studies on the cause of death of these victims have not been conclusive. A previous important step is the understanding of the post-depositional processes and the impact of the plaster in bones, two issues that have not been previously evaluated. Here we report on the anthropological and the first chemical data obtained from the study of six casts from Porta Nola area and one from Terme Suburbane. A non-invasive chemical analysis by portable X-ray fluorescence was employed for the first time on these casts of Pompeii to determine the elemental composition of the bones and the plaster. Elemental profiles were determined providing important data that cross-referenced with anthropological and stratigraphic results, are clearly helpful in the reconstruction of the perimortem and post-mortem events concerning the history of these individuals. The comparative analyses carried out on the bone casts and other collections from burned bones of the necropolis of Porta Nola in Pompeii and Rome Sepolcreto Ostiense, and buried bones from Valencia (Spain), reveal the extent of high temperature alteration and post-depositional plaster contamination. These factors make bioarchaeological analyses difficult but still allow us to support asphyxia as the likely cause of death.

Investigating intentional cranial modification: A hybridized two-dimensional/three-dimensional study of the Hirota site, Tanegashima, Japan

Intentional cranial modification has a long history, being a ubiquitous practice in many cultures around the world for millennia. The crania excavated at the Hirota site on Tanegashima Island, Kagoshima Prefecture, Japan, has been previously noted to have a marked tendency toward a short head and a flattened occipital bone, which has been suggested to be the result of artificial cranial deformation. However, whether this deformation was intentional or caused by unintentional habits remains unclear. This study aimed to investigate the characteristics of the cranial shape of the Hirota site to clarify whether the crania were intentionally modified. In the examination of Hirota crania, Kyushu Island Jomon and Doigahama Yayoi crania were added as comparative data and contrasted with three-dimensional (3D) surface scan imaging and two-dimensional outline-based geometric morphometric analysis, combined with objective assessments of potential cranial modification. The results showcased Hirota's short and flattened cranial morphology, indicating clear alignment with our hypothesis that Hirota samples are morphologically different from Doigahama and Jomon samples. No sex-based differences were found. Morphological abnormalities in cranial sutures were visually assessed utilizing novel 3D visualization methods of cranial outer surfaces. Based on a comprehensive review of the results, we concluded that Hirota site crania were intentionally modified. Although the motivation of the practice is unclear, the Hirota people may have deformed their crania to preserve group identity and possibly aid in the long-distance trade of shellfish, as seen archaeologically.

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.

Title: Skeletal evidence of the ethnic cleansing actions in the Free City of Danzig (1939-1942) based on the KL Stutthof victims analysis

In the early days of World War II, many of the prominent and influential people of Polish nationality from the Free City of Danzig were arrested by the Germans and sent to the nearby concentration camp KL Stutthof. Nearly a hundred of them died within the next seven months upon their arrival, and were buried in a clandestine mass grave in a nearby forest. However, the exact nature of their death is unknown, as it is unclear what the attitude of the aggressors was toward the victims. We do not know whether there was only one executioner or there were several assassins, nor if the killing methodology was consistent with the other state-regulated executions. The studied material represents the commingled remains of a minimum thirty-four people, possibly all male, aged from under eighteen to over sixty at the time of death. Perimortem traumatic lesions are shown mainly on the skull bones. We asked whether the perimortem trauma lesions visible on the victims' skeletons could be informative on the cause and manner of their death. Our results show the prevalence of the perimortem trauma inflicted by a blunt object are on the parietal bones above the Hat Brim Line (HBL), which is commonly associated with a violent attack. The gunshot trauma was usually localized on the occipital bone or posterior parietal, which could indicate a shot to the back of the head, and this was commonly encountered during executions. No signs of defensive injuries can be explained either by restraining of the hands or by a surprise attack. The abundance and variability of the trauma type can be evident of multiple assailants. Moreover, the multiple impact points detected on several crania prove unnecessary overkill and brutality, which reflects the personal attitudes of the executioners towards the victims.

Anthropometric study using three-dimensional pelvic CT scan in sex determination among adult Indonesian population

This study aims to determine pelvic anthropometry characteristics and logistic regression formula for adult sex identification obtained from adult three-dimensional pelvic computed tomography images. This study was an observational analytical study with retrospective regression and cross-sectional approach. The population was all patients at Radiology Installation of Dr. Soetomo General Academic Hospital as referral hospital in East Indonesian region, from September to December 2019 who underwent 3D pelvic CT examination. Then, age distribution and pelvic measurements data were obtained. In this case, statistical analysis was conducted for all the data obtained. A number of 204 samples were included in this study. All radiologic components were also significantly different between sexes (p < 0.05) except for transverse diameter of sacral segment (p = 0.180). Moreover, the conjugate pelvic inlet diameter (CPID), the left innominate height (LIH), and sub pubic angle (SPA) showed significant values for regression formula to determine an adult's sex using 3D pelvic CT. The calculation result > 0 is a prediction for female while < 0 is a prediction for male. From logistic regression model calculation, a high validity value (91.05%) was found with 100% sensitivity to identify male sex and 81.1% specificity to identify female sex. There were differences on radiometric variable characteristics in pelvic anthropometric study among adult Indonesians at Dr. Soetomo General Academic Hospital, Surabaya. The estimated values of pelvic measurements using 3D CT images could develop a pelvic model with a regression formula with high accuracy value using CPID, LIH, and SPA values.

Sex assessment using the radius bone in a French sample when applying various statistical models

Sex estimation of skeletal remains is one of the most important tasks in forensic anthropology. The radius bone is useful to develop standard guidelines for sex estimation across various populations and is an alternative when coxal or femoral bones are not available.The aim of the present study was to assess the sexual dimorphism from radius measurements in a French sample and compare the predictive accuracy of several modelling techniques, using both classical statistical methods and machine learning algorithms.A total of 78 left radii (36 males and 42 females) were used in this study. Sixteen measurements were made. The modelling techniques included a linear discriminant analysis (LDA), flexible discriminant analysis (FDA), regularised discriminant analysis (RDA), penalised logistic regression (PLR), random forests (RF) and support vector machines (SVM).The different statistical models showed an accuracy of classification that is greater than 94%. After selection of variables, the accuracies increased to 97%. The measurements made at the proximal part of the radius (sagittal and transversal diameters of the head, and sagittal diameter of the neck), at distal part (maximum width of the distal epiphysis) and of the entire bone (maximum length) stand out among the various models.The present study suggests that the radius bone constitutes a valid alternative for sex estimation of skeletal remains with comparable classification accuracies to the pelvis or femur and that the non-classical statistical models may provide a novel approach to sex estimation from the radius bone. However, the extrapolation of the current results cannot be made without caution because our sample was composed of very aged individuals.

Conformational variations of the medial epicondyle of the humerus: A case study of fusion anomaly on dry bones

The estimation of a biological profile in biological anthropology is a central point in the study of human remains. To specify this profile, the observation of variations, and pathologies on the skeleton is a tool that makes an individual unique. In this research, the focus was on the distal part of the humerus. Through the study of five individuals from an osteo-archaeological collection, conformational anomalies of the medial epicondyle of the humerus were highlighted. The aim is to describe them and to propose an etiology of appearance. For this purpose, observation of the rest of the skeleton was carried out, in order to search for the presence of other variations, in particular anomalies of fusion of secondary ossification centers. Overall, a non-fusion of the medial epicondyle of the humerus, two fused medial micro-epicondyles and two supplementary fusions were observed. These are very rare anomalies, with an estimated prevalence of 0.7%. Conformational abnormalities of this area can lead to pain. Therefore, medical imaging for diagnostic purposes may be available: useful data for antemortem documentation in case of a disturbing disappearance. Following the study of the entire skeleton, a common etiology for these different conformations cannot be proposed. However, two categories of etiologies can be proposed: a congenital anomaly and a developmental anomaly with an environmental influence (mechanical or deficiency). The new knowledge of this area will enrich the use of individualization factors, especially in the context of forensic anthropology.

The usability of the ratio of bi-humerus breadth to maximum pelvic breadth in sex estimation

BACKGROUND

Although sex can be determined with high accuracy in forensic anthropology, additional parameters are still required.

AIM

To estimate with known simple statistical methods, the usability of the bi-humerus/maximum pelvic breadth ratio in sex estimation.

SUBJECTS AND METHODS

Bi-humerus breadth and maximum pelvic breadth were measured using the topogram images (196 males, 171 females), the ratio between them was calculated. We examined the usability of the ratio of the distance between the lateral edges of the right and left humeral heads to the maximum distance between the two most lateral parts of the iliac crests in sex estimation.

RESULTS

There was significant difference in the bi-humerus breadth and "bi-humerus breadth/maximum pelvic breadth" according to sex. The greatest breadth of the pelvis was higher in females, yet the difference was not statistically significant. The ratio yielded 80.6%-90.3% accuracy for females and 73.6%-74.7% for males, depending on arm position.

CONCLUSIONS

The obtained data may contribute to the development of formulas created with metric measurements used in sex estimation. This can be used as a parameter to help in estimating the sex of skeletal remains found as a whole or excavated without losing their integrity, and also in the reconstruction of body structure.

Biometric sex assessment from the femur and tibia in a modern Greek population

Forensic anthropologists assess sex by analysing quantitative and qualitative characters of the human skeleton. In general, the pelvis and skull are the skeletal regions used most often, but in many cases, they are missing or fragmentary. In such circumstances, where only limb bones are present, it is necessary to use techniques based on other skeletal elements. Metric traits of the long bones of the lower extremities have been reported as reliable indicators of sex. This study was designed to determine whether the two main long bones of the leg, the femur and tibia, can be used for the assessment of sex on a Greek skeletal population. The skeletal sample used in this study comes from the modern human skeletal collection that is currently housed at the National and Kapodistrian University of Athens and is known as The Athens Collection. It consists of 371 femora and 372 tibiae corresponding to 200 adult individuals (111 males and 89 females). The age range is 19-96 years for males and 20-99 years for females. The maximum lengths and epiphyseal widths were measured for the present study, and it was found that the discriminant analysis of the metrical data of each long bone provided high sex discrimination accuracies. The rate of correct sex discrimination based on different long bones ranged from 91.50 % (left femur) to 93.40 % (left tibia). Our results suggest that lower limb bones can be used effectively for sexing in forensic contexts, in addition to other sex assessment techniques.

Efficiency of the Adjusted Binary Classification (ABC) Approach in Osteometric Sex Estimation: A Comparative Study of Different Linear Machine Learning Algorithms and Training Sample Sizes

The adjusted binary classification (ABC) approach was proposed to assure that the binary classification model reaches a particular accuracy level. The present study evaluated the ABC for osteometric sex classification using multiple machine learning (ML) techniques: linear discriminant analysis (LDA), boosted generalized linear model (GLMB), support vector machine (SVM), and logistic regression (LR). We used 13 femoral measurements of 300 individuals from a modern Turkish population sample and split data into two sets: training (n = 240) and testing (n = 60). Then, the five best-performing measurements were selected for training univariate models, while pools of these variables were used for the multivariable models. ML classifier type did not affect the performance of unadjusted models. The accuracy of univariate models was 82−87%, while that of multivariate models was 89−90%. After applying ABC to the crossvalidation set, the accuracy and the positive and negative predictive values for uni- and multivariate models were ≥95%. Sex could be estimated for 28−75% of individuals using univariate models but with an obvious sexing bias, likely caused by different degrees of sexual dimorphism and between-group overlap. However, using multivariate models, we minimized the bias and properly classified 81−87% of individuals. A similar performance was also noted in the testing sample (except for FEB), with accuracies of 96−100%, and a proportion of classified individuals between 30% and 82% in univariate models, and between 90% and 91% in multivariate models. When considering different training sample sizes, we demonstrated that LR was the most sensitive with limited sample sizes (n < 150), while GLMB was the most stable classifier.

Ancient DNA gives new insights into a Norman Neolithic monumental cemetery dedicated to male elites

By integrating genomic and archaeological data, we provide new insights into the Neolithic French monumental site of Fleury-sur-Orne in Normandy, where a group of selected individuals was buried in impressively long monuments. The earliest individuals buried at Fleury-sur-Orne match the expected western European Neolithic genetic diversity, while three individuals, designated as genetic outliers, were buried after 4,000 calibrated BCE. We hypothesize that different, unrelated families or clans used the site over several centuries. Thirteen of 14 of the analyzed individuals were male, indicating an overarching patrilineal system. However, one exception, a female buried with a symbolically male artifact, suggests that the embodiment of the male gender in death was required to access burial at the monumental structures.

The Middle Neolithic in western Europe is characterized by monumental funerary structures, known as megaliths, along the Atlantic façade. The first manifestations of this phenomenon occurred in modern-day France with the long mounds of the Cerny culture. Here, we present genome-wide data from the fifth-millennium BCE site of Fleury-sur-Orne in Normandy (France), famous for its impressively long monuments built for selected individuals. The site encompasses 32 monuments of variable sizes, containing the burials of 19 individuals from the Neolithic period. To address who was buried at the site, we generated genome-wide data for 14 individuals, of whom 13 are males, completing previously published data [M. Rivollat et al., Sci. Adv. 6, eaaz5344 (2020)]. Population genetic and Y chromosome analyses show that the Fleury-sur-Orne group fits within western European Neolithic genetic diversity and that the arrival of a new group is detected after 4,000 calibrated BCE. The results of analyzing uniparentally inherited markers and an overall low number of long runs of homozygosity suggest a patrilineal group practicing female exogamy. We find two pairs of individuals to be father and son, buried together in the same monument/grave. No other biological relationship can link monuments together, suggesting that each monument was dedicated to a genetically independent lineage. The combined data and documented father–son line of descent suggest a male-mediated transmission of sociopolitical authority. However, a single female buried with an arrowhead, otherwise considered a symbol of power of the male elite of the Cerny culture, questions a strictly biological sex bias in the burial rites of this otherwise “masculine” monumental cemetery.

Performance of the supervised learning algorithms in sex estimation of the proximal femur: A comparative study in contemporary Egyptian and Turkish samples

Sex estimation standards are population specific however, we argue that machine learning techniques (ML) may enhance the biological sex determination on trans-population application. Linear discriminant analysis (LDA) versus nine ML including quadratic discriminant analysis (QDA), support vector machine (SVM), Decision Tree (DT), Gaussian process (GPC), Naïve Bayesian (NBC), K-Nearest Neighbor (KNN), Random Forest (RFM) and Adaptive boosting (Adaboost) were compared. The experiments involve two contemporary populations: Turkish (n = 300) and Egyptian populations (n = 100) for training and validation, respectively. Base models were calibrated using isotonic and sigmoid calibration schemes. Results were analyzed at posterior probabilities (pp) thresholds >0.95 and >0.80. At pp = 0.5, ML algorithms yielded comparable accuracies in the training (90% to 97%) and test sets (81% to 88%) which are not modified after employing the calibration techniques. At pp >0.95, the raw RFM, LDA, QDA, and SVM models have shown the best performance however, calibration techniques improved the performance of various classifier especially NBC and Adaboost. By contrast, the performance of GPC, KNN, QDA models worsened by calibration. RFM has shown the best performance among all models at both thresholds whereas LDA benefited the best from using both calibration methods at pp >0.80. Complex ML models are not necessarily achieving better performance metrics. LDA and QDA remain the fastest and simplest classifiers. We demonstrated the capability of enhancing sex estimation using ML on an independent population sample however, differences in the underlying probability distribution generated by models were detected which warranted more cautious application by forensic practitioners.

Sex classification using the human sacrum: Geometric morphometrics versus conventional approaches

The human pelvis shows marked sexual dimorphism that stems from the conflicting selective pressures of bipedal locomotion and parturition. The sacrum is thought to reflect this dimorphism as it makes up a significant portion of the pelvic girdle. However, reported sexual classification accuracies vary considerably depending on the method and reference sample (54%-98%). We aim to explore this inconsistency by quantifying sexual dimorphism and sex classification accuracies in a geographically heterogeneous sample by comparing 3D geometric morphometrics with the more commonly employed linear metric and qualitative assessments. Our sample included 164 modern humans from Africa, Europe, Asia, and America. The geometric morphometric analysis was based on 44 landmarks and 56 semilandmarks. Linear dimensions included sacral width, corpus depth and width, and the corresponding indices. The qualitative inspection relied on traditional macroscopic features such as proportions between the corpus of the first sacral vertebrae and the alae, and sagittal and coronal curvature of the sacrum. Classification accuracy was determined using linear discriminant function analysis for the entire sample and for the largest subsamples (i.e., Europeans and Africans). Male and female sacral shapes extensively overlapped in the geometric morphometric investigation, leading to a classification accuracy of 72%. Anteroposterior corpus depth was the most powerful discriminating linear parameter (83%), followed by the corpus-area index (78%). Qualitative inspection yielded lower accuracies (64–76%). Classification accuracy was higher for the Central European subsample and diminished with increasing geographical heterogeneity of the subgroups. Although the sacrum forms an integral part of the birth canal, our results suggest that its sex-related variation is surprisingly low. Morphological variation thus seems to be driven also by other factors, including body size, and sacrum shape is therefore likely under stronger biomechanical rather than obstetric selection.

Three-dimensional geometric morphometric sex determination of the whole and modeled fragmentary human pubic bone

Sex determination of the human pelvis has traditionally been done through visual analyses of morphoscopic traits and there are limited metric methods available to forensic anthropologists to add metric credibility to these analyses. The goal of this research was to create an improved metric method using three-dimensional geometric morphometrics to determine sex from both whole and modeled fragmented human pubic bones. The sample consisted of n = 378 pubic bones from the University of New Mexico’s Maxwell Museum Documented Skeletal Collection and eight landmarks were collected from each bone. Statistical analyses and machine learning algorithms were used to predict the accuracy of the method’s ability to classify a bone as male or female on both whole and simulated fragmented remains; this included tests run on each possible landmark combination of three or more landmarks to simulate fragmented bones (218 combinations). The results of the whole bone analysis resulted in 95.35% testing accuracy. The results of the modeled fragmentary analysis consisted of 164 combinations which exhibit a 90% or higher accuracy in sex prediction; and twelve combinations which exhibit 96% or higher accuracy in sex prediction. In particular, two landmarks clustered around the ventral arc of the pubic bone performed the best, indicating this is the most sexually dimorphic portion of the bone. These results indicate that three-dimensional geometric morphometrics is a valid method to be applied to sex determination in forensic anthropology.

Whole genome sequence of bacteremic Clostridium tertium in a World War I soldier, 1914

•

This original article is the first report of isolate and culture of a bacterium from ancient human samples and dental pulp in particular.

•

The dental pulp is a mirror of the individual's infectious state at the time of death.

•

Ancient dental pulp culture yielded to the identification and isolation of the bacterium Clostridium tertium responsible for septicaemia during World War I,.

Background

Dental pulp, encapsulating a blood drop, could be used to diagnose pathogen bacteraemia in archaeological materials using DNA-based techniques. We questioned the viability of such ancient pathogens preserved in ancient dental pulp.

Methods

After meticulous decontamination of 32 teeth collected from 31 World War I soldiers exhumed in Spincourt, France, dental pulps were extracted and cultured under strict anaerobiosis. Colonies were identified by mass spectrometry and whole genome sequencing. Fluorescent in situ hybridisation (FISH) was used for the direct microscopic detection of pathogens of interest in the dental pulp. All the experimental procedures included negative controls, notably sediments in contact with individual SQ517 to ensure that results did not arise from contamination.

Findings

Clostridium tertium was detected by FISH in two dental pulp specimens taken from a 1914 soldier. After a two-day incubation period, both dental pulp samples grew colonies identified by mass spectrometry and genome sequencing as C. tertium; whereas negative controls remained free of C. tertium in all the observations, and no C. tertium was founded in sediments. Skeletal remains of this soldier exhibited two notches in the left tibia evocative of a cold steel wound, and a probably fatal unhealed bullet impact in the hip bone.

Interpretation

Data indicated the presence of C. tertium in the dental pulp at the time of the death of one World War I soldier, in 1914. This observation diagnosed C. tertium bacteraemia, with war wounds as the probable portal of entry for C. tertium. Our C. tertium strains ante-dated by three years, the princeps description of this deadly opportunistic pathogen.

Applying posterior probability informed thresholds to traditional cranial trait sex estimation methods

Sex estimation methods using traditional cranial nonmetric traits utilize predictive models to produce a final sex estimation, using the resulting model's score to classify the individual. When sex estimations are assigned from discriminant scoring alone, statistical confidence in the resultant estimate is not always assessed or reported. Although some forensic anthropologists may qualitatively report their confidence in the assessment (e.g., "probable male"), these statements are subjective, not standardized, and not necessarily based on statistical results in a uniform way. The goals of this study were to evaluate how posterior probability-informed thresholds (PPITs) impacted accuracy rates, assess the balance between sample inclusion and accuracy for the proposed PPIT approach, and make recommendations for the use and interpretation of specific thresholds in casework. Using a sample of U.S. Black and White females and males (n = 292), we examined how PPITs can standardize the decision-making process of inferring sex for two methods using nonmetric cranial traits. We found that using PPITs of at least 0.85 increased accuracy (over 92% for some PPITs) yet remained highly inclusive of the sample. PPITs < 0.75 did not produce classification accuracy rates significantly higher than chance, and when using these cranial trait sex estimation methods, cases with posterior probabilities (PPs) <0.75 should be reported as "indeterminate." The 0.75-0.84 PPIT interval had an accuracy rate of 76%, which was both statistically significantly different from chance as well as from the higher (>0.85) groups, suggesting that although sex estimation at this level may be acceptable, the results hold lower confidence.

Sex estimation from the greater sciatic notch: a comparison of classical statistical models and machine learning algorithms

The greater sciatic notch (GSN) is a useful element for sex estimation because it is quite resistant to damage, and thus it can often be assessed even in poorly preserved skeletons. This study aimed to develop statistical models for sex estimation based on visual and metric analyses of the GSN, and additional variables linked to the GSN. A total of 60 left coxal bones (30 males and 30 females) were analysed. Fifteen variables were measured, and one was a morphologic variable. These 16 variables were used for the comparison of six statistical models: linear discriminant analysis (LDA), regularized discriminant analysis (RDA), penalized logistic regression (PLR) and flexible discriminant analysis (FDA), and two machine learning algorithms, support vector machine (SVM) and artificial neural network (ANN). The statistical models were built in two steps: firstly, only with the GSN variables (group 1), and secondly, with the whole variables (group 2), in order to see if the models including all the variables performed better. The overall accuracy of the models was very close, ranging from 0.92 to 0.97 using specific GSN variables. When additional variables starting from the deepest point of GSN are available, it is worth to use them, because the accuracy increases. PLR (after optimization of parameters) stands out from other statistical models. The position of the deepest point of GSN (Fig. 2) probably plays a crucial role for the sexual dimorphism, as stated by the good performance of the visual assessment of this point and the fact that the A2 angle (posterior angle with the deepest point of the GSN as the apex) is included in all models.

Technical Note: The Forensic Anthropology Society of Europe (FASE) Map of Identified Osteological Collections

Identified (documented) osteological collections represent an important resource in the development of forensic anthropology standards and methods as well as a precious tool for learning and training of practitioners. Even though the number of papers presenting identified collections worldwide increases, many of the collections have still not been divulged to the scientific community in sufficient detail to ascertain their exact number. The Forensic Anthropology Society of Europe (FASE) therefore developed a tool that goes beyond sporadic publications: the FASE Map of Identified Osteological Collections, which is freely accessible and continuously updated and revised. The online map is available at http://forensicanthropology.eu/osteological-collections/. The map of skeletal collections was created in 2017 and currently displays information on 153 identified osteological collections (43 of them categorized as contemporary) located in 41 different countries. This article offers a short analysis of the type, geographical location and content of the collections included in the map. The aim of this article and the map as such is to provide a useful resource to facilitate research planning and teaching in forensic anthropology and related disciplines.

Calculation of likelihood ratios for inference of biological sex from human skeletal remains

It is common in forensic anthropology to draw inferences (e.g., inferences with respect to biological sex of human remains) using statistical models applied to anthropometric data. Commonly used models can output posterior probabilities, but a threshold is usually applied in order to obtain a classification. In the forensic-anthropology literature, there is some unease with this "fall-off-the-cliff" approach. Proposals have been made to exclude results that fall within a "zone of uncertainty", e.g., if the posterior probability for "male" is greater than 0.95 then the remains are classified as male, and if the posterior probability for "male" is less than 0.05 then the remains are classified as female, but if the posterior probability for "male" is between 0.05 and 0.95 the remains are not classified as either male or female. In the present paper, we propose what we believe is a simpler solution that is in line with interpretation of evidence in other branches of forensic science: implementation of the likelihood-ratio framework using relevant data, quantitative measurements, and statistical models. Statistical models that can implement this approach are already widely used in forensic anthropology. All that is required are minor modifications in the way those models are used and a change in the way practitioners and researchers think about the meaning of the output of those models. We explain how to calculate likelihood ratios using osteometric data and linear discriminant analysis, quadratic discriminant analysis, and logistic regression models. We also explain how to empirically validate likelihood-ratio models.

A unique case of skeletal dysplasia in an adult male in Late Iron Age Switzerland

OBJECTIVE

We report a probable case of multiple skeletal dysplasia observed in a Late Iron Age young adult male.

MATERIALS

The individual studied belongs to a Late Iron Age necropolis from Switzerland. The skeletal elements are well preserved METHODS: Macroscopic and radiographic assessment.

RESULTS

The individual shows evidence of both craniofacial and mandibular deformation. Developmental defects are also visible with effects on the general shape and articular surfaces of both humeri, as well as the left femur and tibia.

CONCLUSION

We propose that the lesions observed are manifestations of skeletal dysplasia, such as pseudo-achondroplasia or multiple epiphyseal dysplasia.

SIGNIFICANCE

This is the first recorded case of multiple skeletal dysplasia in an Iron Age necropolis in Switzerland, questioning the integration of physically compromised individuals in La Tène society.

LIMITATIONS

Examination of other skeletal dysplasias from archaeological contexts provides support for this diagnosis.

SUGGESTIONS FOR FUTURE RESEARCH

The integration of individuals with disabilities in La Tène societies is still poorly understood and further research is needed to better characterize these communities.

Morphometric analysis of foramen magnum and occipital condyle using CT images for sex determination in a Saudi Arabian population

OBJECTIVE OF THE STUDY

The objective of this study was to evaluate FM and occipital condyles measurements morphometrically for sex determination by using discriminant function analysis and to note visually the variation in the shape of the foramen magnum in a Saudi Arabian population by using CT scan images.

MATERIAL AND METHODS

This study included 472 CT scans (236 males and 236 females; age range, 18-72 years). The foramen magnum shapes were classified into 8 types: oval, egg, round, hexagonal, pentagonal, tetragonal, irregular (A) and irregular (B). The intraobserver and interobserver test was done to calculate the reliability of the measurement. Eight dimensions of the FM and occipital condyle were evaluated to determine the sexual dimorphism using an independent t-test. Sex determination was estimated using discriminate function analysis.

RESULTS

The commonest shape of FM was hexagonal and the tetragonal shape was the least common type. Coefficient of reliability (R) was high, ranging between 0.89 and 0.99, which indicates the measurements are reliable and sufficiently precise. All the eight measurements, the FM length and width, FM index, FM area, the width and length of right and left occipital condyles were significantly greater in males than the female. Univariate discriminant function showed an accuracy rate varying from 61% to 66.6% based on FM or occipital condyles measurements. The multivariate analysis of FM and occipital condyle measurements increased the overall accuracy rate of sex determination to 71.6%.

CONCLUSION

The univariate analysis of FM and occipital condyle measurements indicates, that the FM area (66.1%), FML (62.5%), FMW (62.5%) and ROCL (62.1%) could be reliable individual variables in sex determination. The multivariate analysis including all the eight variables of FM and occipital condyle increased the accuracy rate of sex determination to 71.6% in determining the sex as male (73.3%) or female (69.9%). The shape of the FM is not useful in sex estimation. The results obtained showed a low degree of sexual dimorphism in the basicranium, the use of this method in forensic anthropology could be helpful for assessment on highly fragmented skull bases.

Mechanical metric for skeletal biomechanics derived from spectral analysis of stiffness matrix

A new metric for the quantitative and qualitative evaluation of bone stiffness is introduced. It is based on the spectral decomposition of stiffness matrix computed with finite element method. The here proposed metric is defined as an amplitude rescaled eigenvalues of stiffness matrix. The metric contains unique information on the principal stiffness of bone and reflects both bone shape and material properties. The metric was compared with anthropometrical measures and was tested for sex sensitivity on pelvis bone. Further, the smallest stiffness of pelvis was computed under a certain loading condition and analyzed with respect to sex and direction. The metric complements anthropometrical measures and provides a unique information about the smallest bone stiffness independent from the loading configuration and can be easily computed by state-of-the-art subject specified finite element algorithms.

How low can we go? A skeletal maturity threshold for probabilistic visual sex estimation from immature human os coxae

OBJECTIVES

The appearance of sexually dimorphic traits varies depending on the type of bone, age, environmental and genetic factors and is closely linked to skeletal maturation sequence. Subadult sex estimation currently shows inconsistent accuracy and methods do not incorporate indicators of maturation. The goal of this study is to apply the Santos et al. (2019) adult sex estimation method on virtually reconstructed subadult os coxae and account for pelvic maturation.

MATERIAL AND METHODS

The right os coxae of 194 female and male individuals aged 11-30 years from Marseille, France were virtually reconstructed from computed tomography (CT) scans. Santos et al.'s (2019) 11 traits were scored as female, male, or indeterminate. Maturation of 10 pelvic epiphyseal sites was scored using a four-stage system (0-3) to obtain a composite maturity score from 1 to 30.

RESULTS

Three maturity groups were identified based on composite maturity scores ranging from 0 to 30. Individuals with a composite maturity score of 15 or higher showed 98 % sex estimation accuracy and a 6 % indeterminate rate. Scores of 2 for the ischiatic tuberosity or 1 for the anterior superior iliac spine can be used as proxies for a composite maturity score of 15 and application on incomplete bones.

DISCUSSION

Sexual dimorphism was observed in the epiphyseal maturation sequence and the development of sexually dimorphic pelvic traits. The Santos et al. (2019) method is applicable on immature individuals who meet a maturation threshold with comparable accuracy to adults, without relying on known or estimated age.

New insights on interpersonal violence in the Late Pleistocene based on the Nile valley cemetery of Jebel Sahaba

The remains of 61 individuals buried in the cemetery of Jebel Sahaba (site 117) offer unique and substantial evidence to the emergence of violence in the Nile Valley at the end of the Late Pleistocene. Excavated and assessed in the 1960s, some of the original findings and interpretations are disputed. A full reanalysis of the timing, nature and extent of the violence was conducted through the microscopic characterization of the nature of each osseous lesion, and the reassessment of the archaeological data. Over 100 previously undocumented healed and unhealed lesions were identified on both new and/or previously identified victims, including several embedded lithic artefacts. Most trauma appears to be the result of projectile weapons and new analyses confirm for the first time the repetitive nature of the interpersonal acts of violence. Indeed, a quarter of the skeletons with lesions exhibit both healed and unhealed trauma. We dismiss the hypothesis that Jebel Sahaba reflects a single warfare event, with the new data supporting sporadic and recurrent episodes of inter-personal violence, probably triggered by major climatic and environmental changes. At least 13.4 ka old, Jebel Sahaba is one of the earliest sites displaying interpersonal violence in the world.

The size and shape of the human pelvis: a comparative study of modern and medieval age populations

INTRODUCTION

Great variability in shape and size of the bony pelvis can be observed in the current population, but there is not enough data on how long the historical period must elapse to gain changes in pelvic shape and size. The aim of the study was to identify morphological changes in bony pelvis in males and females after a developmentally short period of approximately one thousand years.

MATERIAL AND METHODS

Seventeen defined external dimensions of pelvic bone from 120 adult individuals (two craniocaudal, two ventrodorsal, six mediolateral, three acetabular dimensions, and four dimension of the auricular surface) were measured. The medieval sample of 60 pelvic bones (30 male and 30 female) was obtained from the Great Moravian site of Mikulčice-Valy (9th-10th century), while the modern collection of 60 pelvic bones (30 male and 30 female) dates from the late 19th and first half of the 20th centuries. Obtained results were evaluated using the independent t-test at a 5% level of significance.

RESULTS

A comparison of male and female pelvic dimensions within a single population yielded expected results: the mean male values were greater. In modern population, male pelvis mean values were greater in 15 of defined parameters, while in medieval population, male dimensions were larger in 16 variables. A comparison of modern and medieval female pelvic bones found 11 variables to be greater in medieval sample (one determining the craniocaudal dimension, five the mediolateral, all three the acetabular, and two determining the auricular surface dimensions), but only two were significant (two dimensions determining the mediolateral dimensions). In modern female samples, there were five variables greater (one determining the craniocaudal dimension, one the ventrodorsal, one the mediolateral, and two determining the auricular surface dimensions), but only two were significant as well (one determining the craniocaudal and one the ventrodorsal dimensions). A comparison of male pelvic bones found 13 variables to be greater in medieval pelvis (one determining the craniocaudal dimension, all six the mediolateral, one the ventrodorsal, all three the acetabular, and two determining the auricular surface dimensions), but only four were significant as well (all determining the mediolateral dimensions). In modern male sample, there were only four variables greater (one determining the craniocaudal dimension, one the ventrodorsal, and two determining the auricular surface dimensions), but only one was significant (determining the craniocaudal dimension).

CONCLUSION

Unexpectedly, our study did not find the early medieval population to have a smaller pelvis compared to the modern population. While pelvic bones of the former were somewhat lower, but wider, those of the latter population were a bit higher and narrower. The study allows a very careful statement that one millennium is a time period long enough for measurable morphological deviations of the pelvic bones shape and size to occur.

Sex estimation from knee breadth dimensions in a Finnish population

Sex estimation is an important part of osteological analysis of skeletons and forensic identification process. Traditionally cranial and pelvic traits are utilized for accurate sex estimation. However, post-cranial measurements have also been proven to accurately estimate sex especially from robust bones such as the femur. In this study, we investigated the potential of knee breadth dimensions in sex estimation in a Finnish population. To conduct this study we utilized a study sample (n = 1654) belonging to the Northern Finland Birth Cohort 1966. All individuals were 46 years of age at the time of the examination. Three knee breadth dimensions were measured from subjects' knee posteroanterior radiographs: femoral biepicondylar breadth (FBEB), mediolateral breadth of the femoral condyles (FCML), and mediolateral breadth of the tibial plateau (TPML). Sex estimation was performed using logistic regression. The study clearly demonstrated that all three measurements were different between males and females. Sectioning points for individual knee breadth measurements were 82.9 mm for FBEB, 76.6 mm for FCML and 75.4 mm for TPML. The classification rates ranged from 90.9% to 93.6%. The less commonly used measurements of FCML and TPML showed higher accuracy than FBEB in sex estimation. Our study confirmed that knee breadths can be successfully utilized to improve sex estimation in cases where the skeleton is only partially preserved and other major components of sex estimation are absent. We can also provide new standards for sex estimation from the knee joint in a Finnish population.

Age-related differences in cranial sexual dimorphism in contemporary Europe

Biomechanical load and hormonal levels tended to change just like the soft and skeletal tissue of the elderly with age. Although aging in both sexes shared common traits, it was assumed that there would be a reduction of sexual dimorphism in aged individuals. The main goals of this study were (1) to evaluate age-related differences in cranial sexual dimorphism during senescence, (2) to determine age-related differences in female and male skulls separately, and (3) to compare skull senescence in Czech and French adult samples as discussed by Musilová et al. (Forensic Sci Int 269:70-77, 2016). The cranial surface was analyzed using coherent point drift-dense correspondence analysis. The study sample consisted of 245 CT scans of heads from recent Czech (83 males and 59 females) and French (52 males and 51 females) individuals. Virtual scans in the age range from 18 to 92 years were analyzed using geometric morphometrics. The cranial form was significantly greater in males in all age categories. After size normalization, sexual dimorphism of the frontal, occipital, and zygomatic regions tended to diminish in the elderly. Its development during aging was caused by morphological changes in both female and male skulls but secular changes must also be taken into account. The most notable aging changes were the widening of the neurocranium and the retrusion of the face, including the forehead, especially after the age of 60 in both sexes. Sexual dimorphism was similar between the Czech and French samples but its age-related differences were partially different because of the population specificity. Cranial senescence was found to degrade the accuracy of sex classification (92-94%) in the range of 2-3%.

Sexing the bony labyrinth: A morphometric investigation in a subadult and adult Belgian identified sample

In forensic anthropology, sex estimation is a fundamental step in assessing individual biological profiles when analyzing human skeletons. Yet, current methods are not reliable enough to allow an accurate sex identification of highly fragmented, burnt, or subadult remains. This paper aims to investigate sexual dimorphism of the bony labyrinth on both identified subadult and adult individuals. The bony labyrinth is of particular interest for sex estimation since it is alleged to complete size and maturation pre-pubertally and is located inside the petrous part of the temporal bone which protects it from taphonomic processes. The study was performed on 93 CT scans of identified individuals from two Belgian osteological collections (19-20th century) and from current pediatric images (Erasme hospital, Brussels). Linear and angular measurements were taken on 2D slices of right bony labyrinths. Intra- and interobservers error measurements were calculated. Statistical tests were used to unravel any morphological variations between subadult and adult bony labyrinths and to highlight differences between females and males, separately in subadults and adults. Linear discriminant functions were established by cross-validation and tested on an independent sample from Belgium. Some measurements were significantly different between subadults and adults, and between females and males within both subadult and adult samples. Univariate functions achieved 72.7% in subadults and 68.4% in adults whereas multivariate equations increased accuracy respectively up to 84.9% and 78.4%. This study entails promising results to design a sex estimation method suitable for fragmented and/or subadult remains. Further metric approaches are needed to explore bony labyrinth sexual dimorphism.

Adjusted binary classification (ABC) model in forensic science: An example on sex classification from handprint dimensions

Binary classification techniques are commonly used in forensic examination to test if a specimen belongs to a particular group and base the expert opinion on the questioned evidence. However, most of the currently used methods do not achieve sufficient accuracy due to the ignoring of the specimens classified in the overlapping area. To address the issue, we proposed a novel Adjusted binary classification (ABC) algorithm that automatically adjusts posterior probabilities to reach classification accuracy and positive/negative predicted values (PPV, NPV) of 95 %. In the presented example, we used three handprint measurements from 160 participants (80 males and 80 females) to develop models that would classify sex from their dimensions. The sample was split into the training/cross-validated (70 %) and testing sample (30 %). We developed four classification models using linear discriminant analysis (LDA) by employing traditional single cut-off values and ABC approach that for each group provides a specific posterior probability cut-off threshold. In the cross-validated sample, the accuracy of traditional models was 78.7-92.5 %, while PPVs/NPVs ranged between 78.2 and 93 %. ABC models provided 95 % accuracy, PPV, and NPV, and could classify 35.5-88.1 % of specimens. In the testing sample, ABC models achieved accuracy of 97.3-100 %, PPV/NPV 95.4-100 %, and could be applied to 29.1-87.5 % of specimens. The study demonstrated that the ABC approach could adjust classification models to reach predefined values of accuracy, PPV, and NPV. Therefore, it could be an efficient tool for conducting a binary classification in forensic settings and minimizing the possibilities of incorrect classifications.