In molars without permanent eruption, wear deeply modifies the geometry of the crown. To test for a signature of diet on wear dynamics, the molar geometry was compared between commensal house mice, relying on an omnivorous-granivorous diet, and Sub-Antarctic relatives, characterized by a switch towards a more 'predatory' behaviour. Laboratory-bred offspring of commensal mice served as a reference by providing mice of known age. Molar geometry was quantified using dense 3D semi-landmark based descriptors of the whole molar row and the upper molar only.Laboratory offspring displayed a decreased rate of wear compared to their commensal relatives, due to reduced mastication in mice fed ad libitum. Sub-Antarctic mice displayed a similarly decreased rate of molar wear, in agreement with an optimization towards incisor biting to seize prey. Laboratory offspring and Sub-Antarctic mice were further characterized by straight molar rows, whereas in commensal mice, the erupting third molar deviated away from the longitudinal alignment with the other molars, due to masticatory loadings.Quantifying changes in molar geometry could thus contribute to trace subtle diet variations, and provide a direct insight into the constraints during mastication, shedding light on the functional role of adaptive changes in molar geometry.
This contribution contains 3D models of upper molar rows of house mice (Mus musculus domesticus) belonging to Western European commensal and Sub-Antarctic feral populations.These two groups are characterized by different patterns of wear and alignment of the three molars along the row, related to contrasted masticatory demand in relation with their diet.These models are analyzed in the following publication:
Abstract This article studies the discoid Didacna sp. shell beads discovered at Kaylu, a Middle Holocene burial site located in Southern Turkmenistan. Microscopic, morphometric, spectrometric, and SEM analyses were carried out on the material to identify how the beads were manufactured and used. New radiocarbon dating and bioanthropological data to age and sex the two skeletons discovered in the burials are provided. A regional synthesis shows that personal ornaments from the Caspian region were diversified through time and that a stylistic shift between the last foragers and the first farmers occurred. We also observed strong correspondences between the personal ornaments documented in the northern, eastern, and western Caspian Sea during the Neolithic, with no evidence of similar symbolic production in Northern Iran. We propose that a northern route may have allowed the diffusion of common ornamental traditions in the Caspian region to the exclusion of the southern Caspian. Alternatively, discontinuities in material culture diffusion in coastal areas could be evidence of maritime voyaging. Seafaring may have granted the fast and spatially erratic diffusion of specific bead types, people, information, knowledge, and symbols from both sides of the Caspian Sea, by long maritime voyages or by leapfrog diffusion during the Neolithic.
Personal ornaments are a very specific kind of material production in human societies and are particularly valuable artifacts for the archaeologist seeking to understand past societies. In the Caribbean, Early Ceramic Age sites have yielded a highly diverse production both in terms of raw materials and typology. In recent years they have been the subject of renewed interest, mainly based on the diversity and provenance of raw materials, and on typological similarity, used as proxies for exchange networks, social interactions and the evolution of these phenomena through the Ceramic Age. Meanwhile, the chaîne opératoire for lithic beads and pendants has not been investigated in detail, including the process of creating narrow perforations in quartz beads several centimeters long. This hard material (7 on the Mohs scale), represented as rock crystal and amethyst in the collections, is indeed very difficult to perforate without the use of metal drills or harder minerals used as drill-bits or abrasives such as diamond or emery. In this work we demonstrate that it is possible to produce these perforations with cactus thorns and crushed quartz as abrasive powder. We also show that the wear created by our experimental work is fully comparable to the stigmata visible on the archaeological artifacts. This process, using only materials available to Ceramic Age people, also accounts for the absence of both adequate drills and production wastes of quartz beads in the archaeological record. The investment of Ceramic Age inhabitants of the Lesser Antilles in the production of the many beads made of very hard material recovered in archaeological excavations is once again highlighted. The perforation process, not investigated in detail so far in this archaeological context, has to be taken into account in the value of these highly symbolic artifacts, in addition to the exotic provenance of the raw material.
Molar morphology is shaped by phylogenetic history and adaptive processes related to food processing. Topographic parameters of the occlusal surface, such as sharpness and relief, can be especially informative regarding diet preferences of a species. The occlusal surface can however be deeply modified by wear throughout an animal's life, potentially obliterating other signals. Age being difficult to assess in wild populations, especially small rodents, experimental studies of wear through age in laboratory populations may constitute a powerful way to assess its impact on molar geometry and topography, and to validate descriptors of molar morphology that could mitigate this issue. Molar morphology was therefore quantified using 3D geometric morphometrics and topographic estimates in four groups of house mice: wild‐trapped mice, lab‐bred offspring of these wild mice, typical laboratory mice, and their hybrids. Three descriptors of the molar morphology were considered: the surface of the whole molar row, the surface of the first upper molar, and a truncated template of the first upper molar mimicking advanced wear. Increasing wear with age was demonstrated in the different groups, with a more pronounced effect in the wild‐trapped population. The geometry of the molar row is not only modified by wear, but also by the relative position of the late developing molars on the jaw due to loading during mastication. As a consequence, the alignment of the molars is modified in wild mice, showing a qualitative difference between wild animals and their lab‐bred offspring. Results obtained from the lab should thus be transferred with caution to the interpretation of differences in wild populations. Topographic estimates computed for the first upper molar seems to provide more stable parameters than those based on the whole molar row, because issues related to non‐planar occlusal surface along the molar row are discarded. The truncated template was proven efficient in discarding the wear effect to focus on genetic differences, allowing an efficient characterization of the hybridization signature between wild and lab mice. Dominance of the wild phenotype for the first molar shape supports that the lab strain evolved in a context of relaxation of the selective pressures related to nutrition.
AbstractHigher education in evolutionary anthropology involves providing students with in‐depth knowledge of biological and cultural heritage sites and collections that are frequently inaccessible. Indeed, most sites, fossils, and archaeological remains can be visited or manipulated only rarely and solely by specialists with extensive experience. Owing to the development of 3D and medical imaging techniques, this fragile heritage is now more widely accessible, and in a dynamic way. However, exclusive adoption of virtual teaching and learning has a negative impact on student engagement and, naturally, on exchanges with instructors, and thus cannot be used without some reservations. In the ITAP (Immersion dans les Terrains de l’Anthropologie biologique et de la Préhistoire) project of the higher education STEP (Soutien à la Transformation et à l’Expérimentation Pédagogiques) transformation program at the University of Bordeaux, we combine student‐active teaching with Master's students fully immersed in ongoing fieldwork, laboratory study, and dissemination of research results in order to develop more individually shaped learning curricula and to foster both professional and new interdisciplinary skills. Here, we present examples of experiments conducted in the ITAP project using both authentic and virtual collections of archaeological, experimental, and reference materials that help to break down the barriers between research activities and higher education, as well as providing a more general appraisal of the appropriate use of virtual tools in higher education by combining them with real‐life situations.
Past bird communities are still under-studied in several Caribbean regions, including the Lesser Antilles. In order to improve our understanding of this area’s avifauna, we explore morphometrical variations of the carpometacarpus (CMC) within West Indies Mimidae species. We combine geometric morphometric (GMM) and conventional osteology focusing on characters of the entire or distal portion of the CMC. Morphological variation related to their phylogenetic history is investigated using uni- and multi-variate statistics, and the expression of certain osteological characters. Fossil bone remains from the Guadeloupe Islands were included in the datasets to test the applicability of these results to the archaeological and paleontological record. Our results are consistent with the known phylogeny of Mimidae. The GMM analysis clearly differentiated taxa at both inter- and intra-generic levels, which when combined with osteological characters, allow fossil specimens to be determined to species. For the fossil record of Guadeloupe Islands, this concerns three taxa: the Scaly-breasted Thrasher 'Allenia fusca', the Gray Catbird 'Dumetella carolinensis', the first fossil occurrence of this bird in the Greater and Lesser Antilles, and the Brown Trembler 'Cinclocerthia ruficauda' in Desirade and Marie-Galante, where the bird is now extirpated. These results are of particular interest for tracking the impact of environmental changes on the composition of West Indian bird communities.
Conodont animals were early jawless vertebrates equipped with a feeding apparatus composed of several tooth-like elements. The P1 elements, at the rear of the apparatus, were characterized by a robust shape and rapid morphological evolution. Occlusion occurred between paired right and left P1 elements, occasioning some bilateral asymmetry, which, together with allometric growth, may partially obliterate the temporal differences. The present study aims to disentangle these different components of morphological variation in Late Devonian Polygnathus P1 conodont elements. An extensive 2D geometric morphometric analysis of the platform shape was performed through the Famennian record of two outcrops. This analysis was completed by a 3D study on a subset of conodont elements. The 2D and 3D morphometric quantifications provided highly congruent results, showing that the 2D shape constitutes a good approximation of the element geometry. The 3D analysis delivered further insights into the relationship between the geometry of the elements and the constraints related to occlusion. The 2D analysis allowed a quantitative assessment of the variation among species and through time. Allometry and bilateral asymmetry were differently expressed depending on the species considered, suggesting that constraints imposed on pairing by the morphology of the elements varied even among related species. The within-species variation was so important that it largely obliterated temporal trends; a relationship of Polygnathus shape and conodont biofacies variations through the Famennian nevertheless suggested an evolution driven by ecological interactions between conodont genera.
This contribution contains the 3D models of the set of Famennian conodont elements belonging to the species Polygnathus glaber and Polygnathus communis analyzed in the following
The recent identification of cave paintings dated to 42-40 ka BP in Borneo and Sulawesi highlights the antiquity of painted representations in this region. However, no instances of three-dimensional portable art, well attested in Europe since at least 40 ka BP, were documented thus far in East Asia prior to the Neolithic. Here, we report the discovery of an exceptionally well-preserved miniature carving of a standing bird from the site of Lingjing, Henan, China. Microscopic and microtomographic analyses of the figurine and the study of bone fragments from the same context reveal the object was made of bone blackened by heating and carefully carved with four techniques that left diagnostic traces on the entire surface of the object. Critical analysis of the site's research history and stratigraphy, the cultural remains associated with the figurine and those recovered from the other archeological layers, as well as twenty-eight radiometric ages obtained on associated archeological items, including one provided by a bone fragment worked with the same technique recorded on the object, suggest a Late Paleolithic origin for the carving, with a probable age estimated to 13,500 years old. The carving, which predates previously known comparable instances from this region by 8,500 years, demonstrates that three-dimensional avian representations were part of East Asian Late Pleistocene cultural repertoires and identifies technological and stylistic peculiarities distinguishing this newly discovered art tradition from previous and contemporary examples found in Western Europe and Siberia.
The house mouse (Mus musculus domesticus), as a successful invasive species worldwide, has to forage a variety of resources. Subantarctic mice display among the most notable diet shift from the usual omnivorous-granivorous diet, relying on a larger proportion of terrestrial animal prey. In agreement, a recent study of their mandible morphology evidenced an evolution of their mandible shape to optimize incisor biting and hence seize preys. Here, the incisors themselves are the focus of a morphometric analysis combined with a 3D study of their internal structure, aiming at a comparison between subantarctic populations (Guillou island, Kerguelen archipelago) with a range of western European continental, commensal mice. The predatory foraging behavior of Guillou mice was indeed associated with a sharper bevel of the lower incisor, which appears as an efficient morphology for piercing prey. The incisor of these mice also displays a reduced pulp cavity, suggesting slower eruption counterbalancing a reduced abrasion on such soft food material. The dynamics of the ever-growing incisor may thus allow adaptive incisor sculpting and participate to the success of mice in foraging diverse resources.
The planktonic foraminifera genus Globigerinoides provides a prime example of a species-rich genus in which genetic and morphological divergence are uncorrelated. To shed light on the evolutionary processes that lead to the present-day diversity of Globigerinoides, we investigated the genetic, ecological and morphological divergence of its constituent species. We assembled a global collection of single-cell barcode sequences and show that the genus consists of eight distinct genetic types organized in five extant morphospecies. Based on morphological evidence, we reassign the species Globoturborotalita tenella to Globigerinoides and amend Globigerinoides ruber by formally proposing two new subspecies, G. ruber albus n.subsp. and G. ruber ruber in order to express their subspecies level distinction and to replace the informal G. ruber “white” and G. ruber “pink”, respectively. The genetic types within G. ruber and Globigerinoides elongatus show a combination of endemism and coexistence, with little evidence for ecological differentiation. CT-scanning and ontogeny analysis reveal that the diagnostic differences in adult morphologies could be explained by alterations of the ontogenetic trajectories towards final (reproductive) size. This indicates that heterochrony may have caused the observed decoupling between genetic and morphological diversification within the genus. We find little evidence for environmental forcing of either the genetic or the morphological diversification, which allude to biotic interactions such as symbiosis, as the driver of speciation in Globigerinoides.
OBJECTIVES:A marked asymmetry was previously reported in the sacral alae and S1-L5 facets orientation of the Neandertal individual Regourdou 1. Here, we provide a detailed description and quantification of the morphology and degree of asymmetry of this sacrum.MATERIAL AND METHODS:Regourdou 1 was compared to a modern human sample composed of 24 females and 17 males, and to other Neandertal individuals. Both traditional and geometric morphometric analyses were used in order to quantify the degree of sacral asymmetry of Regourdou 1.RESULTS:The asymmetry of both sacral alae and facets orientation substantially exceeds directional and absolute asymmetry of the healthy modern sample. Regourdou 1 shows a considerably shorter right ala, which is absolutely and relatively outside of the modern and Neandertal variations.CONCLUSION:Regourdou 1 shows marked sacral asymmetry that probably originated in early ontogenetic development. An asymmetric sacrum reflects asymmetric load dissipation and could relate to other morphological abnormalities observed in the skeleton, especially the mild scoliosis of the spine and the asymmetry of the femoral diaphyses. Further investigation is necessary to elucidate the relationship between those morphologies as well as a potential impact on the life of the individual.