Juvenile and Infant Osteology

We studied the postnatal development of the skull of Noctilio leporinus, examining the relationship between ectocranial elements, including shape changes and sutures closure and fusion. Most shape changes and structure development were observed at subadults and adults; zygomatic arch, sagittal crest, occipital process and mandibular processes developed noticeably up to the adult stage. Cranial sutures closure and fusion sequences of N. leporinus agree with that of hystricomorph rodents, artiodactyls, primates, sirenians and carnivores, beginning with the cranial vault followed by the basicranium, supporting a conserved pattern for mammalia. Detailed comparisons exhibit a complete cranial sutures fusion reached earlier at Desmodus rotundus regarding N. leporinus and Pteropus sp., and an early fusion for the sutura coronalis plus late fusion for the sutura sagittalis at N. leporinus regarding Desmodus rotundus. The drastic shape changes of cranial elements, as well as sutures closure and fusion in N. leporinus at subadults and adults, seem to be closely related to the acquisition of morphological specializations during stages of development when the fisher bat begins to feed independently.

Here we evaluate Bhattacharya et al.’s (2018) recent paper “Whole-genome sequencing of Atacama skeleton shows novel mutations linked with dysplasia” published in Genome Research. In this short report, we examine the hypothesis that the so-called “Atacama skeleton” has skeletal abnormalities indicative of dysplasia, critique the validity of the interpretations of disease based on genomic analyses, and comment on the ethics of research on this partially mummified human foetus. The current paper acts as a case study of the importance of using an anthropological approach for aDNA research on human remains. A critical evaluation of the ethically controversial paper by Bhattacharya et al. highlights how an understanding of skeletal biological processes, including normal and abnormal growth and development, taphonomic processes, environmental context, and close attention to ethical issues of dealing with human remains, is vital to scientific interpretations. To this end, close collaboration with palaeopathologists and local archaeologists through appropriate peer-reviewed journals will add to the rigour of scientific interpretation and circumvent misinterpretation.

Recent studies have reported that quantifying symphyseal and auricular surface curvature changes on 3D models acquired by laser scanners has a potential for age estimation. However, no tests have been carried out to evaluate the repeatability of the results between different laser scanners. 3D models of the two pelvic joints were generated using three laser scanners (Custom, Faro, and Minolta). The surface curvature, the surface area, and the distance between co-registered meshes were investigated. Close results were found for surface areas (differences between 0.3% and 2.4%) and for distance deviations (average <20 lm, SD <200 lm). The curvature values were found to be systematically biased between different laser scanners, but still showing similar trends with increasing phases/scores. Applying a smoothing factor to the 3D models, it was possible to separate anatomy from the measurement error of each instrument, so that similar curvature values could be obtained (p < 0.05) independent of the specific laser scanner. Recent studies have shown the benefits of quantitative methods using 3D laser scanner models in addressing fundamental issues in physical and forensic anthropology. Sexual dimorphism and population and ancestry variation have been investigated quantifying surface areas or extracting curves (1–5). The morphological features of the symphyseal and the auricular surfaces used for age estimation have been examined looking at the surface curvature changes (6–8). Laser scanners have also been used to investigate cranial facial variation and for facial identification (9–13). In all these applications, the precision and the repeatability of the measurements among different instruments are essential for the reliability of each method; in fact, there are different models of laser scanners and differences between the software used for postprocessing the scans (i.e., aligning, merging, and fusion of the single scans to create a 3D model). It has been demonstrated that the surface areas were reproduced with high precision and the measurement errors of the extracted information varied from 0.2% to about 1% (5,14); it has been also shown that the location of points on the surface (landmarks) and the measurements of length could be accurately repeated on 3D models (11,12,15). When some of the parameters used for the scans made by the same laser scanner have been changed, measurement error was reported to increase slightly to 2% (14). However, all these studies have tested the repeatability of measurements made by the same instrument. Laser surface scanning (and CT-scanning) of bones is proposed as a method to make osteological data more widely and easily available, for example, the Smithsonian 3D collection (16), " Digitised Diseases " (17) and " From Cemetery to Clinic " (18). It is thus important to investigate whether 3D models acquired by different laser scanners may exhibit larger differences than those acquired by the same scanner. Irrespective of the performance of each laser scanner, the nodes of the resulting 3D model surfaces represent the true anatomical shape, plus some error due to measurement uncertainty. The formal expression of this uncertainty is difficult, as it requires full knowledge not only of the instrument and object properties, but also of operational details which may not always be available, such as calibration steps followed and the exact distance between object and scanner (19,20). A simple but general approach to assess measurement error that does not rely on any external knowledge beyond the scanned 3D mesh would therefore be particularly convenient. We assumed the measurement uncertainty manifests itself exclusively as independent random error in the position of mesh nodes, which can be effectively reduced by a smoothing operation over neighboring nodes. If this assumption is appropriate , the use of an adequate amount of smoothing would filter out the measurement error while preserving the overall anatomical shape of the bone surface and homogenize 3D models from different instruments. The aim of this study was to experimentally verify the validity of our assumption using 3D models of sym-physeal and auricular surfaces generated with three different

Examination of three frozen bodies, a 13-y-old girl and a girl and boy aged 4 to 5 y, separately entombed near the Andean summit of Volcán Llullaillaco, Argentina, sheds new light on human sacrifice as a central part of the Imperial Inca capacocha rite, described by chroniclers writing after the Spanish conquest. The high-resolution diachronic data presented here, obtained directly from scalp hair, implies escalating coca and alcohol ingestion in the lead-up to death. These data, combined with archaeological and radiological evidence, deepen our understanding of the circumstances and context of final placement on the mountain top. We argue that the individuals were treated differently according to their age, status, and ritual role. Finally, we relate our findings to questions of consent, coercion, and/or compliance, and the controversial issues of ideological justification and strategies of social control and political legitimation pursued by the expansionist Inca state before European contact.