Individual Skeletons Research Articles

Osteometric characteristics of the Medieval population of Northern Sudan (based on materials from the Deraheib monument)

Introduction. Paleoanthropological studies of Medieval North African materials are extremely few. Despite the large number of international expeditions working in the region, very few results of craniometric and osteometric data are presented. This is partly due to the loss of practical measurement skills in European anthropological schools in the second half of the 20th century, partly due to the difficulties of studying the graves of the Islamic period. Several seasons of work of the Nubian Archaeological and Anthropological Expedition of the Research Institute and the Museum of Anthropology of Lomonosov Moscow State University on the Southern Necropolis of the medieval site Derakheyb (Republic of Sudan) were devoted to the study of this population. The purpose of the publication is characteristics of the medieval population buried in the Southern Necropolis of the Derakheyb site due to osteological features and introducing the new data. Materials and methods. The material is the bones of the postcranial skeleton of adult individuals (14 men and 9 women). The technique corresponds to the classical program in the modification of V.P. Alekseev (a total of 74 signs and 16 pointers). The reconstruction of the body length was carried out, the total body dimensions were described, and the proportion indicators were calculated. For intra-group analysis, the principal component method was used, which was carried out using individual data using the R language. Results and discussion. The male population is characterized by average total body size and shoulder width, while the female series is relatively narrow-shouldered. In the male series, the distal parts of the arms and legs are elongated relative to the proximal ones, and the lower limbs are elongated relative to the upper ones. The women's series featured a more graceful physique. The distal part of the leg is elongated relative to the proximal one, as in the male group; there is also some shortening of the upper limbs relative to the lower ones. Body length varies between 166 cm for men and 156 cm for women. Conclusion. According to osteometry data, the medieval population of the city of Derakheyb can be characterized as heterogeneous, the individuals that stand out mainly correspond to those that stood out according to craniological data. The male part of the population is medium-massive, and the female part is graceful. The entire sample is characterized by shortened lower limbs relative to the arms, as well as elongated distal parts of the arms and legs relative to the proximal ones, which reflects one of the features of the tropical adaptive type.

Vitamin D deficiency, pregnancy, and childbirth in early medieval Milan

This paper explores the burden of osteomalacia on pregnancy and childbirth through two cases from early medieval urban Milan. Two skeletons of female individuals with skeletal deformities and associated with 25–36 gestational weeks fetuses, excavated from the Ad Martyres and San Vittore al Corpo urban cemeteries and dated to the Early Middle Ages, were examined. Paleopathological and historical analyses were performed in a biocultural approach to investigate the impact of clinical complications and skeletal deformities on their daily life, the course of their pregnancy, and childbirth. The women showed severe skeletal deformities attributable to osteomalacia including scoliosis, reduced rib-neck angle, coxavara, severe bending of the pelvic bones, protrusio acetabuli, and narrowed pelvic outlet. The condition and its biomechanical complications impacted the health of both mothers and fetuses, the quality of life of the women (i.e., gait alteration, difficult and limited mobility, compression of internal organs), as well as pregnancy outcomes. It is possible that both the mothers and fetuses died due to childbirth complications. Bioarchaeological cases of osteomalacia, pregnancy, and death during childbirth are excessively rare. This paper also provides insight into how maternal experiences and biocultural environments in early medieval Milan impacted childbirth outcome. The study of the Ad Martyres and San Vittore al Corpo necropolises is still ongoing and could provide further insight. Isotopic and paleogenomic analyses may shed more light into the factors that led to vitamin D deficiency in these women.

Utility of the metatarsal diaphyseal nutrient foramen in estimating sex in the South African Africans population

IntroductionSex estimation is challenging in cases where dismembered or non-intact skeletal remains are recovered. Therefore, the development of sex estimation standards using various bones that present with high recovery rates during forensic investigations, like the metatarsal bones, is needed. The usefulness of the dimensions around the metatarsal diaphyseal nutrient foramen in sex estimation has not been assessed in South African Africans (SAA), constituting the majority of the country's population. Materials and methodsFive measurements around the nutrient foramen were taken from 995 metatarsal bones (first to fifth) from 200 individual skeletons (100 males, 100 females). Measurements subjected to direct and stepwise discriminant function (DFA) and logistic regression (LRA) analyses included the total length, distance from proximal end to nutrient foramen, circumference, and mediolateral and dorsoplantar diameters at the level of the nutrient foramen. ResultsThe original classification accuracies for multivariable functions of the stepwise and direct DFA ranged from 75.1 to 80 % and 76–79.5 % respectively. The original classification accuracies for multivariable functions of the stepwise and direct LRA ranged from 76.3% to 79.5 % and 75%–80.5 % respectively. The cross-validation classifications showed a drop of 0–2% for DFA and 0.2–1.9 % for LRA. Overall breadth measurements showed better classification accuracies than length measurements and females were classified with higher accuracy rates than males. ConclusionThe dimensions around the nutrient foramen of the metatarsal bones show sexual dimorphism in the SAA. The generated DFA and LRA functions produced high average classification accuracies which can be appropriate for use in sex estimation in forensic settings, especially when an isolated foot is recovered.

Comparison between cervical vertebrae of man and of the domestic animals

Anatomy is the science that studies the form, architecture and structure of living beings, and the modality that explores the morphological differences between species is called comparative anatomy. Among the bone structures that make up the axial skeleton of individuals, the cervical vertebrae stand out, considered odd and irregular bones. Given the relevance of cervical vertebrae, the objective of the present study was to compare such bone elements in humans and domestic animals (dogs, horses and cattle) and, nevertheless, highlight the structural similarities in these different species in terms of quantities, functions and formats in resulting from bone accidents. For this, skeletons and individual anatomical pieces from the Human and Veterinary Anatomy Laboratory of the University of Franca (UNIFRAN - Franca, SP) were used, as well as anatomy books renowned in this area of ​​specialty and scientific articles. The results were presented in a descriptive way. As for quantity, humans have seven cervical vertebrae, just like dogs, horses and cattle. In all species, the cervical vertebrae support the neck, providing movement of the head and protection of the cervical spinal cord. Regarding shape, the first (atlas) and second (axis) cervical vertebrae are atypical in all species. The atlas has an arched body, containing the dorsal and ventral tubercle; furthermore, the transverse process is modified (wing of the atlas) with the alar foramen and lateral vertebral foramen. The caudal articular surface of the atlas (fovea dentis) articulates with the odontoid process of the axis. Cattle do not have a transverse foramen and, in no species, does the spinous process appear in the atlas. The axis had a rod-shaped odontoid process in dogs, concave in cattle and pointed in other species, in addition to an elongated spinous process. The other cervical vertebrae are typical, composed of a vertebral body (with head of the vertebra and vertebral fossa), vertebral arch (participates in the formation of the vertebral foramen), vertebral foramen (houses the spinal cord) and spinous processes (poorly developed), transverse (well developed, containing the transverse foramen) and cranial and caudal articular (flat surfaces). In all species, the seventh cervical vertebra is modified, presenting a long spinous process and reduction or absence of the transverse foramen; furthermore, in horses, the spinous process was detected only in this vertebra. In humans, dogs, horses and cattle, the seventh cervical vertebra has a pair of caudal costal facets for articulation with the first pair of ribs. Given the results obtained, it is accepted that the anatomical morphological similarities and differences between the cervical vertebrae may be related to the functional, evolutionary and postural aspects of the different species studied.

Impaired muscle parameters in adults with mild to severe types of osteogenesis imperfecta: a cross-sectional study.

Impaired muscle parameters may further compromise the already compromised skeleton in individuals with OI. This cross-sectional study aimed to compare muscle function and body composition in adults with various OI types and healthy controls. Sixty-eight adults with OI (mean age 42.2yr; 27 men) and 68 healthy age- and sex-matched controls were recruited. Maximal isometric muscle force was assessed by handheld dynamometry (hand grip, hip flexors, shoulder abductors, and ankle dorsiflexors), muscle endurance by posture maintenance tests (shoulder abduction, hip flexion, and wall sit), and functional lower limb strength by 30-s chair rise test. In a sub cohort, dynamic muscle function (peak power and force) was assessed by a ground reaction force plate, and lean and fat mass, muscle and fat cross-sectional area (CSA), and muscle density by dual-energy X-ray absorptiometry and peripheral quantitative computed tomography. Multiple linear regression models were fitted with group (OI type I, III, IV/V, or controls), country, sex, and age in the fixed effects part. Overall, adults with various types of OI had lower isometric, endurance, and functional muscle strength (mean difference [MD] = OI type I: 19-43%, OI type IV/V: 25-68%, OI type III: 20-72%) compared to controls. Furthermore, adults with OI type I had lower dynamic muscle function (peak force [MD = 25-29%] and power [MD = 18-60%]), lean mass (MD = 10-17%), muscle CSA (MD = 9-21%), and muscle density (MD = 2-3%) but higher adiposity indices (MD = 24-42%) compared to controls. Functional lower limb strength and maximal muscle force were significantly different between OI types, whereas muscle endurance was not. To conclude, adults with OI present with markedly impaired muscle function which may partially be explained by their altered body composition. Our findings emphasize the need for proper assessment of various muscle parameters and (research into) appropriate and safe muscle strengthening approaches in this population.

The skeletal completeness of the Palaeozoic chondrichthyan fossil record.

Chondrichthyes (sharks, rays, ratfish and their extinct relatives) originated and diversified in the Palaeozoic but are rarely preserved as articulated or partly articulated remains because of their predominantly cartilaginous endoskeletons. Consequently, their evolutionary history is perceived to be documented predominantly by isolated teeth, scales and fin spines. Here, we aim to capture and analyse the quality of the Palaeozoic chondrichthyan fossil record by using a variation of the skeletal completeness metric, which calculates how complete the skeletons of individuals are compared to estimates of their original entirety. Notably, chondrichthyan completeness is significantly lower than any published vertebrate group: low throughout the Silurian and Permian but peaking in the Devonian and Carboniferous. Scores increase to a range similar to pelycosaurs and parareptiles only when taxa identified solely from isolated teeth, scales and spines are excluded. We argue that environmental influences probably played an important role in chondrichthyan completeness. Sea level significantly negatively correlates with chondrichthyan completeness records and resembles patterns already evident in records of ichthyosaurs, plesiosaurs and sauropodomorphs. Such observed variations in completeness highlight the impact of different sampling biases on the chondrichthyan fossil record and the need to acknowledge these when inferring patterns of chondrichthyan macroevolution.

Вычислительный фантом для дозиметрии красного костного мозга пятилетнего ребенка от инкорпорированных бета-излучателей

The red bone marrow (RBM) exposure due to bone-seeking radionuclides can lead to grave medical consequences. In particular, the increased risk of leukemia in people exposed due to contamination of the Techa River in 1950s is associated with the RBM exposure due to 89,90Sr. Improvement of the internal RBM dosimetry methods includes the development of computational phantoms that represent 3D models of the skeletal sites. Modeling radiation transport within such phantoms enables estimation of conversion factors from the radionuclide activity in the bone to the RBM dose rate. This paper is an extension study focused on generating a set of computational phantoms representing skeletons of individuals of different ages. The aim was to develop a computational phantom representing a 5-yearold child for internal RBM dosimetry from incorporated beta emitters. The phantoms of the skeletal sites with active hematopoiesis were created using the original Stochastic Parametric Skeletal Dosimetry (SPSD) method. With this method, every such site represented a set of smaller phantoms of simple geometric shape. RBM distribution across the skeleton, bone size, characteristics of bone micro-architecture, as well as density and chemical composition of the simulated media (RBM, bone) were determined based on the published data. As a result, a computational phantom of the major skeletal sites with active hematopoiesis representing a 5-year-old child was generated that included 43 phantoms of bone fragments. Linear dimensions of phantoms were within 3–75 mm. Micro-architecture parameters varied greatly: BV/TV ratio —13–52%, Tb. Th. — 0.09–0.29 mm, Tb. Sp. —0.48–0.98 mm.

Dense orchard landscape mapping based on image merging with skeleton prediction

To address the difficulty of individual vine-plant segmentation in large orchards, this study proposes a segmentation model for individual canopies that combines the characteristics of tree deciduousness and natural growth patterns. This enables the landscape mapping of orchards under intensive planting conditions. In this study, winter and summer unmanned aerial vehicle (UAV) remote-sensing images of kiwifruit orchards were used for canopy segmentation. It involved: 1) target location identification of tree trunks in winter images and alignment of winter and summer image information; 2) semantic segmentation of branches in winter images; 3) screening of individual skeletons and prediction of branch growth; 4) removal of non-canopy parts of summer images using digital image processing to obtain canopy leaf segmentation results; and 5) segmentation of the extent of the individual plant canopies based on the predicted results of the individual plants. The branch precision rate for the final kiwifruit canopy at the plant level was 99.25% and the recall rate was 95.96%. The average recall rate of the canopy precision segmentation was 82.79%, the accuracy rate of which was 73.31%. This model does not involve plant height information and can implement instance segmentation of deciduous trees of the same species, with similar characteristics, and dense planting. The proposed solution addresses the problem of large-scale standardized planting of the same species, especially those that do not have obvious height or color differences and cannot be segmented using a digital elevation model.

The Free State Collection for Anthropological Research (FS-CAR): a new contemporary identified skeletal collection in South Africa

Documented skeletal collections are valuable resources for anthropological studies aimed at reconstruction of the biological profile and examination of osteological trauma and pathology. The Free State Collection for Anthropological Research is a new, contemporary skeletal collection, based in central South Africa that has become available for such studies. This paper aims to provide an overview of the collection to encourage its future use in national and international research. The collection currently contains 64 female and 122 male skeletons of individuals that have died in the Free State province since the year 2000. Black individuals constitute 94.6% of the collection. Age-at-death ranges between 19 and 86 years, with an overall mean of 40 years. Year-of-birth ranges from 1927 to 1991. Tuberculosis (22.6%) and influenza/pneumonia (20.4%) are the most common cause of death for these individuals. Although the current demographic profile of the collection is skewed, new individuals are continuously being added. The collection offers several opportunities for anthropological research. The relatively young age-at-death and contemporary nature of the collection make it a useful tool for validation of existing methods for estimations of components of the biological profile. It can also be used in conjunction with other collections for the development of new methods for age and sex estimation and studies of trauma and disease manifestation of the skeleton.

STARC OSTEOARCH: An open access resource for recording and sharing human osteoarchaeological data

AbstractThis paper introduces an open access resource for recording and sharing macroscopic data on archaeological human skeletal remains: STARC OSTEOARCH. The resource was developed using a cloud collaboration service, Airtable, and it accommodates data collection on individual skeletons as well as disassociated commingled remains. The attributes covered include key information on demography (sex and age‐at‐death), taphonomy (zonation, anatomical preservation, weathering, fragmentation, and other types of post‐mortem alteration), diet (dental diseases and dental wear), mechanical stress (entheseal changes, osteoarthritis, Schmorl's nodes, and vertebral arthritis), biodistances (cranial metrics and nonmetrics and dental metrics and nonmetrics), and various pathological lesions. References and key descriptions of the categories per attribute have been incorporated in the resource to facilitate raw data sharing, which can be achieved using Airtable's sharing functionality. This initiative aims at promoting standard practices in the field and facilitating data collection and sharing.

Антропологические материалы из погребальных комплексов сарматского времени (могильник Вонючка-1, Кавказские Минеральные Воды)

Introduction. Most of the burial mounds of the Caucasian Mineral Waters region combine the burials of representatives of different archaeological cultures separated by thousands of years. Therefore, the rate of accumulation of monocultural synchronous materials in collections for some epochs is quite low, and slows down even more due to the unequal preservation of bone remains. The introduction of new information into scientific circulation based on the results of recent archaeological work will allow faster accumulation of materials and data exchange between researchers working on the same issue. The purpose of this work is to publish morphological features of the skeleton of individuals belonging to the Sarmatian culture of the Pre-Caucasus. Materials and methods. The skeletons of three individuals, from three burials of one mound, dating from the III-I centuries BC and belonging to the nomads of the early Sarmatian time were investigated. The study used both traditional methods of anthropology and bioarchaeological approaches. Sex and age studies were carried out on all preserved parts of the skeleton according to standard anthropological methods. A program for fixing markers of stress and pathological conditions was applied to all the studied individuals. Results. Skeletal remains of two young women and a mature man were studied. Both women had anomalies in the development of teeth: in one case – underdevelopment of enamel, in the other – partial congenital adentia. A set of specific features on the postcranial skeleton of a man allow us to characterize him as a rider, right-handed. Discussion. The results of the study supplement our knowledge about the variability of morphological features of the skeleton of representatives of the nomads of the early Sarmatian culture. Some of the detected signs have a pronounced genetic determination; however, the data obtained is insufficient to identify kinship ties, despite the fact that according to the interpretation of archaeologists, this group of burials is defined as a generic cemetery created during the lifetime of one generation. All the discovered features of the skeleton find analogies among the published materials of synchronous time. @ 2023. This work is licensed under a CC BY 4.0 license.

An ancient coronavirus from individuals in France, circa 16th century

ObjectivesAt the time when the COVID-19 pandemic was responsible for more than six million deaths worldwide, the antiquity of coronaviruses remains undefined. We investigated individuals buried during the 16th century in France for the direct and paleoserological diagnosis of the coronavirus. MethodsThe 2011-2012 excavation of Abbey Saint-Pierre in Baume-Les-Messieurs, France uncovered 12 skeletons of individuals from the 13th to the 18th century. The total proteins extracted from dental pulps were subjected to microbial paleoserology, targeting SARS-CoV-2, human-associated coronavirus (HCoV)-229E, and OC43 antigens and for coronavirus peptide research using metaproteomics, in parallel to negative controls. ResultsThree peptide sequences totaling 36 amino acids indicative of a coronavirus were retrieved from the dental pulp remains collected from two individuals buried circa 16th century, in whom paleoserology confirmed a specific immunological response against modern-day SARS-CoV-2 and HCoV-229E. ConclusionWe provide serological and proteomic evidence for a betacoronavirus with no modern correspondent, infecting populations in the 16th century, extending the antiquity of coronaviruses by more than three centuries. Historical, archaeozoological, and paleoproteomic data suggested close contacts between these two individuals and domestic swine, cattle, and poultry, suggesting an ancient zoonotic coronavirus. Coronaviruses have been undesirable companions of populations long before the ongoing coronavirus disease 2019 outbreak emerged.

SMAM: Self and Mutual Adaptive Matching for Skeleton-Based Few-Shot Action Recognition.

This paper focuses on skeleton-based few-shot action recognition. Since skeleton is essentially a sparse representation of human action, the feature maps extracted from it, through a standard encoder network in the few-shot condition, may not be sufficiently discriminative for some action sequences that look partially similar to each other. To address this issue, we propose a self and mutual adaptive matching (SMAM) module to convert such feature maps into more discriminative feature vectors. Our method, named as SMAM-Net, first leverages both the temporal information associated with each individual skeleton joint and the spatial relationship among them for feature extraction. Then, the SMAM module adaptively measures the similarity between labeled and query samples and further carries out feature matching within the query set to distinguish similar skeletons of various action categories. Experimental results show that the SMAM-Net outperforms other baselines on the large-scale NTU RGB+D 120 dataset in the tasks of one-shot and five-shot action recognition. We also report our results on smaller datasets including NTU RGB+D 60, SYSU and PKU-MMD to demonstrate that our method is reliable and generalises well on different datasets. Codes and the pretrained SMAM-Net will be made publicly available.

New species from the early Eocene London Clay suggest an undetected early Eocene diversity of the Leptosomiformes, an avian clade that includes a living fossil from Madagascar

We report the first records of the leptosomiform taxon Plesiocathartes from the early Eocene London Clay of Walton-on-the-Naze (Essex, UK). Two species could be distinguished, one of which is described as Plesiocathartes insolitipes, sp. nov. (the other is classified as Plesiocathartes sp.). We furthermore describe two small leptosomiform-like birds from Walton-on-the-Naze, Waltonavis paraleptosomus, gen. et sp. nov. and W. danielsi, gen. et sp. nov., which are represented by partial skeletons of multiple individuals. In plesiomorphic characters of the coracoid and furcula, the new taxon Waltonavis is distinguished from Plesiocathartes and the extant Leptosomus; the skull of Waltonavis furthermore exhibits basipterygoid processes, which are absent in Leptosomus. Another new species, Lutavis platypelvis, gen. et sp. nov., is based on a partial skeleton from Walton-on-the-Naze and closely resembles Plesiocathartes in the overall shape of the tarsometatarsus. However, L. platypelvis is clearly distinguished from leptosomiform birds in the morphology of the hypotarsus, the more massive coracoid, and other skeletal features. Although we consider close affinities to Plesiocathartes and, hence, the Leptosomiformes to be possible, we could not identify derived characters that enable an unambiguous phylogenetic placement of L. platypelvis. In any case, the new species document an unexpected diversity of Plesiocathartes-like fossil in the London Clay and may open a new perspective for a reconstruction of the ancestral morphology of the avian clade Afroaves, which includes the Leptosomiformes and other arboreal landbirds.

The association between skeletal lesions and tuberculosis in a pre-antibiotic South African sample

ObjectiveThis study assessed the sensitivity and specificity of skeletal lesions to accurately diagnose TB in a pre-antibiotic South African skeletal sample. MaterialsA total of 435 skeletons of individuals who died before 1950 from the Raymond A. Dart Collection of Human Skeletons. 176 died of TB, 109 died of other pulmonary diseases, and 150 died of other causes. MethodsThe presence / absence of 23 skeletal lesions were assessed for differences in frequency between groups. Sensitivities and specificities were calculated and compared to Dangvard Pedersen et al. (2019). ResultsLesions on the ventral surface of thoracic and lumbar vertebral bodies were observed significantly more often in TB and pulmonary cases than in other cause of death group and yielded a 55% probability of a true TB diagnosis, if observed. An association between skeletal lesions and TB was found for rib and vertebral lesions. ConclusionsThe results suggest that even when not documented to have died of TB, TB-related changes are observed in many individuals in a South African skeletal sample, indicating that they may have been infected with the disease. SignificanceThe study provides information that can assist palaeopathologists in making inferences about the prevalence of TB in past populations. LimitationsSample sizes were small, and the inclusion of a pulmonary disease group may have confounded the results. Suggestions for further researchThe selection of a control group without any possible contact with TB may improve the results and should be investigated.

Elemental Imaging of Long-term Gadolinium Retention in Rodent Femur.

Background The use of gadolinium-based contrast agents (GBCAs) is linked to gadolinium retention in the skeleton of healthy individuals. The mechanism of gadolinium incorporation into bone tissue is not fully understood and requires spatially resolved analysis to locate the gadolinium. Purpose To compare the quantitative distribution of gadolinium retained over time in rodent femur following the administration of gadodiamide and gadobutrol at three different time points. Materials and Methods In this animal study conducted between May 2018 and April 2020, 108 9-week-old healthy rats were repeatedly injected with either gadodiamide, gadobutrol, or saline solution and were killed 1, 3, or 12 months after the last injection. The femurs of six female and six male rats per each group and time point were collected. Quantitative elemental imaging of gadolinium in longitudinal thin sections was performed on one sample per sex with use of laser ablation inductively coupled plasma mass spectrometry (ICP-MS). Gadolinium concentration was determined with use of ICP-MS on the samples of all animals (six per group). Mann-Whitney U tests were applied on pairwise comparisons to determine potential sex effect and GBCA effect on gadolinium concentrations. Results The highest gadolinium retention was observed in the gadodiamide group (concentration, 97-200 nmol · g-1), exceeding the mean concentration in the gadobutrol group (6.5-17 nmol · g-1). However, the gadolinium distribution pattern was similar for both contrast agents, showing prominent gadolinium retention at endosteal surfaces, in the bone marrow, and in small tissue pores. Gadolinium distribution in cortical bone changed over time, initially showing a thin rim of higher concentration close to the periosteum, which appeared to grow wider and move toward the interior of the femur over 1 year. Conclusion For both gadolinium-based contrast agents, gadolinium retention in rat bone was initially located close to the periosteum and bone cavities and changed with bone remodeling processes. The relevance to long-term storage of gadolinium in humans remains to be determined. © RSNA, 2022 Online supplemental material is available for this article.

Skeletal and soft tissue completeness of the acanthodian fossil record

AbstractAcanthodians are a poorly understood paraphyletic grade of extinct Palaeozoic fishes. They play an increasingly prominent role in our understanding of vertebrate evolution as part of the chondrichthyan stem‐group even though their evolutionary history is scarce. The limited preservation of their mostly cartilaginous skeleton largely results in a bias towards isolated remains such as fin spines and scales. Here, we quantify the quality of the acanthodian fossil record by using a variation of the Skeletal Completeness Metric (SCM), an approach that calculates how complete the skeletons of individuals are compared to their theoretical complete skeleton. A novel Soft Tissue Completeness Metric (STCM) is introduced to estimate the percentage of soft body tissue preserved as an alternate measurement of completeness. Completeness scores for >1600 specimens comprising >300 taxa obtained from museum collection visits and literature surveys were assembled into a database. Acanthodian completeness peaks in the Lower–Middle Devonian, Pennsylvanian, and earliest Permian. There is no correlation between acanthodian taxonomic richness and completeness. Acanthodians show a significantly lower completeness distribution than many tetrapod groups, but a similarly low distribution to bats. Skeletons deposited in freshwater are significantly more complete than in marine environments where sea level significantly negatively correlates with observed completeness. Our assessment reveals only weak spatial biases influencing the acanthodian fossil record while environmental biases are much higher. This quantified evaluation of acanthodians provides a foundation for further assessments of the likely influence of character absences from morphological datasets on estimates of early chondrichthyan and, therefore, early gnathostome evolution.

Dynamics of the Zebrafish Skeleton in Three Dimensions During Juvenile and Adult Development.

Zebrafish are a valuable model for normal vertebrate skeletogenesis and the study of myriad bone disorders. Bones grow, ossify and change shape throughout the zebrafish lifetime, and 3D technologies allow us to examine skeletogenic processes in detail through late developmental stages. To facilitate analysis of shape, orientation and tissue density of skeletal elements throughout ontogeny and adulthood, we generated a high-resolution skeletal reference dataset of wild-type zebrafish development. Using microCT technology, we produced 3D models of the skeletons of individuals ranging from 12 to 25 mm standard length (SL). We analyzed the dynamics of skeletal density and volume as they increase during juvenile and adult growth. Our resource allows anatomical comparisons between meristic units within an individual—e.g., we show that the vertebral canal width increases posteriorly along the spine. Further, structures may be compared between individuals at different body sizes: we highlight the shape changes that the lower jaw undergoes as fish mature from juvenile to adult. We show that even reproductively mature adult zebrafish (17–25 mm SL) continue to undergo substantial changes in skeletal morphology and composition with continued adult growth. We provide a segmented model of the adult skull and a series of interactive 3D PDFs at a range of key stages. These resources allow changes in the skeleton to be assessed quantitatively and qualitatively through late stages of development, and can serve as anatomical references for both research and education.

First application of a puberty estimation method to skeletons of young pregnant females: A case for the reevaluation of maternal–fetal burials

AbstractThe objective of this study was to evaluate the pubertal status of skeletons belonging to young females who died while pregnant to better understand puberty, the attainment of reproductive capacity, pregnancy, and maternal and fetal mortality in the past. A method to analyze pubertal development in osteological remains was applied to three skeletons of pregnant individuals from different medieval Spanish cemeteries. Pelvic measurements, stature estimates, and pathology studies were also employed. One pregnant individual, determined to have possibly been “at risk” for a complicated delivery, was found to be pubescent having died during the maturation phase of the pubertal growth spurt. Two Hispano‐Muslim individuals were both postpubescent, although one had passed this milestone not long before death. This study is the first of its kind to apply puberty determination methodology to the skeletons of pregnant individuals and as such, was able to identify the skeleton of a pregnant, but still pubescent, girl in an archaeological collection. Delays observed in reaching the later pubertal stages prolonged puberty and could have enabled girls to become pregnant before having achieved complete maturity. The authors suggest that this skeleton is not one of a kind and believe it necessary to consider the reevaluation of maternal–fetal burials making use of pubertal status determination methods. In this way, puberty, the early reproductive stages, and motherhood in the past can be better understood.

Constructing a multiple‐part morphospace using a multiblock method

Abstract Popular current methods for quantifying variation in biological shape are well‐suited to analyses of isolated parts (e.g. the same bone from the skeletons of many individuals). An analytical challenge exists for quantifying variation between the shapes of multiple‐part objects where each part has a different position, rotation or scale (e.g. partial or whole articulated skeletons). We investigated regularised consensus principal component analysis (RCPCA) as a multiblock method for quantifying variation in the shape of multiple‐part objects. Multiblock methods are routinely used in other big data research fields such as bioinformatics/medicine, marketing and food research, but have not been widely embraced for evolutionary biology research. We have created the new package morphoBlocks for the r programming language to make RCPCA more accessible for shape evolution research. morphoBlocks provides a complete workflow for formatting, analysing and visualising the variation between multiple‐part objects by integrating functions from a diverse range of other packages. In particular, global components produced by RCPCA provide a consensus space that we present here as a morphospace for multiple‐part objects. morphoBlocks is demonstrated with a case study of manually placed landmarks and automatically placed pseudolandmarks from the partial wing skeletons of 15 extant penguin species and five fossil penguin species. Our case study provides quantitative support for a historical hypothesis about the magnitude and mode of morphological change across the evolutionary history of penguins. RCPCA can be used to analyse two‐ or three‐dimensional datasets with 10s of landmarks, or 100s to 1,000s of semilandmarks or pseudolandmarks, from 10s to 100s of specimens comprised of two or more parts. We use morphoBlocks on a small three‐bone case study and provide a framework for applying this method to much larger studies investigating the ecological or evolutionary significance of multiple‐part objects.