Dental Microwear Texture Analysis Research Articles

Investigating the dietary niches of fossil Plio-Pleistocene European macaques: The case of Macaca majori Azzaroli, 1946 from Sardinia

The genus Macaca includes medium- to large-bodied monkeys and represents one of the most diverse primate genera, also having a very large geographic range. Nowadays, wild macaque populations are found in Asia and Africa, inhabiting a wide array of habitats. Fossil macaques were also present in Europe from the Late Miocene until the Late Pleistocene. Macaques are considered ecologically flexible monkeys that exhibit highly opportunistic dietary strategies, which may have been critical to their evolutionary success. Nevertheless, available ecological information regarding fossil European species is very sparse, limiting our knowledge of their evolutionary history in this geographic area. To further our understanding of fossil European macaque ecology, we investigated the dietary ecology of Macaca majori, an insular endemic species from Sardinia. In particular, we characterized the dental capabilities and potential dietary adaptations of M. majori through dental topographic and enamel thickness analyses of two M2s from the Early Pleistocene site of Capo Figari (1.8 Ma). We also assessed its diet through dental microwear texture analysis, while the microwear texture of M. majori was also compared with microwear textures from other European fossil macaques from mainland Europe. The dental topographic and enamel thickness analyses suggest that M. majori frequently consumes hard/mechanically challenging and/or abrasive foods. The results of the dental microwear analysis are consistent with this interpretation and further suggest that M. majori probably exhibited more durophagous dietary habits than mainland Plio-Pleistocene macaques. Overall, our results indicate that M. majori probably occupied a different dietary niche compared to its mainland fossil relatives, which suggests that they may have inhabited different paleoenvironments.

Three-dimensional dental microwear in type-Maastrichtian mosasaur teeth (Reptilia, Squamata)

Mosasaurs (Squamata, Mosasauridae) were large aquatic reptiles from the Late Cretaceous that filled a range of ecological niches within marine ecosystems. The type-Maastrichtian strata (68–66 Ma) of the Netherlands and Belgium preserve remains of five species that seemed to have performed different ecological roles (carnivores, piscivores, durophages). However, many interpretations of mosasaur diet and niche partitioning are based on qualitative types of evidence that are difficult to test explicitly. Here, we apply three-dimensional dental microwear texture analysis (DMTA) to provide quantitative dietary constraints for type-Maastrichtian mosasaurs, and to assess levels of niche partitioning between taxa. DMTA indicates that these mosasaurs did not exhibit neatly defined diets or strict dietary partitioning. Instead, we identify three broad groups: (i) mosasaurs Carinodens belgicus and Plioplatecarpus marshi plotting in the space of modern reptiles that are predominantly piscivorous and/or consume harder invertebrate prey, (ii) Prognathodon saturator and Prognathodon sectorius overlapping with extant reptiles that consume larger amounts of softer invertebrate prey items, and (iii) Mosasaurus hoffmanni spanning a larger plot area in terms of dietary constraints. The clear divide between the aforementioned first two groups in texture-dietary space indicates that, despite our small sample sizes, this method shows the potential of DMTA to test hypotheses and provide quantitative constraints on mosasaur diets and ecological roles.

Dental microwear texture analysis reveals a likely dietary shift within Late Cretaceous ornithopod dinosaurs

AbstractDinosaurs were the dominant megaherbivores during the Cretaceous when angiosperms, the flowering plants, emerged and diversified. How herbivorous dinosaurs responded to the increasing diversity of angiosperms is largely unknown due to the lack of methods that can reconstruct diet directly from body fossils. We applied dental microwear texture analysis (DMTA), an approach that quantifies microtopography of diet‐induced wear marks on tooth surfaces, to ornithopods, the dinosaur clade that includes taxa with the most sophisticated masticatory system. We found that Late Cretaceous ornithopods have significantly rougher dental microwear texture (DMT) compared to pre‐Late Cretaceous ornithopods, and DMT variation increased in hadrosaurids, a derived Late Cretaceous ornithopod clade. These changes indicate a likely temporal dietary shift towards more abrasive foodstuffs within ornithopods, probably due to the increased ingestion of phytoliths (amorphous silica bodies in plants). Phytoliths are a main source of rough DMT in modern herbivores, along with exogenous dust and grit, and were generally more concentrated in Late Cretaceous angiosperms than in other major plant groups. Our results show that DMTA of the occlusal enamel surface can be used to reconstruct the diets of herbivorous dinosaurs, with a resolution superior to conventional methods.

Tree-climbing in search of fruit: an ancient arboreal marsupial megafrugivore from the Miocene of Australia

Diprotodontids, a group of large-bodied wombat-like marsupial herbivores, were broadly distributed in Australasian Cenozoic deposits. While most diprotodontids were terrestrial quadrupeds and are often compared to placental herbivores like rhinoceros and hippopotamuses, the zygomaturine diprotodontid Nimbadon lavarackorum, based on its post-cranial morphology, is thought to have occupied the treetops. Understanding the dietary ecology of N. lavarackorum during the Miocene can help clarify potential motivations for an arboreal lifestyle. Here, we conducted dental microwear texture analysis (DMTA) and stable isotope analysis (SIA) of N. lavarackorum specimens from the Riversleigh World Heritage Area and compared them to analogous extant mammals to assess the likelihood that these tree-dwelling marsupials occupied a unique ecological niche during the Miocene in Australia—arboreal megafrugivores. The DMTA of N. lavarackorum (i.e., low anisotropy and high complexity) is most similar to extant mammals that include a high proportion of fruit in their diet and is inconsistent with and statistically distinct from obligate folivores. Stable carbon isotopes of N. lavarackorum also indicate the consumption of C3 food sources, consistent with the consumption of 13C enriched fruit in a C3 forest environment. Fruits may have been a motivation for this ca 70 kg marsupial moving into or staying in the treetops—an ecological niche that is currently unoccupied in Australia today.Larisa DeSantis [larisa.desantis@vanderbilt.edu], Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA; Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN 37240, USA; Michael Archer [m.archer@unsw.edu.au], Earth and Sustainability Science Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia; Karen Black [k.black@unsw.edu.au], Earth and Sustainability Science Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia; Suzanne Hand [s.hand@unsw.edu.au], Earth and Sustainability Science Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia; Vera Korasidis [vera.korasidis@unimelb.edu.au], Department of Geography, Earth and Atmospheric Sciences, University of Melbourne, Parkville, VIC, 3010, Australia.

The diet of young Neandertals from France, Pech de l’Azé I and Hortus II, reconstructed using dental microwear texture analysis

The diet of young Neandertals from France, Pech de l’Azé I and Hortus II, reconstructed using dental microwear texture analysis

Discriminating dietary behaviour between wild and domestic goats using dental microwear texture: first results from a modern reference set and early Neolithic goat exploitation in the southern Levant

Current evidence supports the idea that animal domestication occurred in multiple loci and at different time periods throughout the Near East rather than according to a single origin. In this scenario, the southern Levant is being increasingly considered as another presumed primary centre of goat domestication, alongside eastern Anatolia and the Zagros. Assessing the status (i.e. wild or domestic) of this animal in this region, however, is hampered by the difficulty of morphologically distinguishing domestic goats from their wild relatives. Diet reconstruction is a powerful approach to address this issue since the feeding of managed animals is partially controlled by their owners, unlike free-ranging wild populations. For the first time, we propose to contribute to this question through dental microwear texture analysis (DMTA) using confocal microscopy.Characterising how the dietary behaviour of extant wild and domestic goats is reflected in DMTA is critical. For this purpose, we constructed a reference collection composed of three wild goat species (19 Capra pyrenaica from the southern Iberian Peninsula, 12 Capra ibex from the Alps and 12 Capra nubiana from the Near East) and 15 domestic goats (Capra hircus) reared in an extensive system in Mediterranean scrubland areas.The preliminary results indicate that DMTA allows discrimination of the groups of extant goats. The results obtained were used to characterise the palaeodiet of 16 goats (Capra format aegagrus) from two key Early and Middle Pre-Pottery Neolithic B sites in the southern Levant: Kharaysin (Zarqa, Jordan, ca. 8800-7500 cal BC) and Qarassa (As-Suweyda, Syria, 8700-8200 cal BCE). The higher variability in archaeological goats could be an indicator of controlled feedings. It could also support the hypothesis about diverse and experimental management systems at the first steps of animal domestication.This paper shows the potential of this tool to address the process of early animal domestication. Following this initial work, the reference collection will include a broader spectrum of livestock management strategies and the archaeological corpus will be expanded through new samples during upcoming excavations and the integration of additional sites.

Coyotes Reveal Baseline Nitrogen Decline Across End-Pleistocene Ecosystem Collapse

The end Pleistocene was a time of ecological turmoil, coincident with environmental change, extinctions, and anthropogenic impacts on the landscape. As one of the few persisting predators from the Pleistocene, La Brea’s exceptional record of coyotes (Canis latrans) provides a unique opportunity to clarify how a recently documented ecosystem state-shift impacted survivors. Through a multiproxy analysis of Rancho La Brea coyotes from the past 50,000 years to present, we analyzed over 100 individuals for radiocarbon chronologies, stable isotopes, dental microwear, and morphology to assess the consequences of megafaunal extirpation on these predators. Most notably, coyotes demonstrate a significant decline in δ15Nbone collagen values immediately after the extirpation of megafauna. While this decline is suggestive of a change in diet from more to less meat, stable isotopes of amino acids from a subset of samples instead provide evidence of a baseline shift in nitrogen—indicating large scale changes in the availability of nutritional resources. While coyotes do not demonstrate notable changes in diet across the extirpation boundary, as inferred from stable carbon isotopes in tooth enamel and dental microwear texture analysis, significant shifts in stable oxygen isotopes in δ18Oenamel and δ13Cbone collagen indicate more nuanced changes in potential prey-resources. Coyotes also demonstrate a linear decline in body size that begins prior to the local extirpation of megafauna (~20,000 years ago) and may be in response to competition with larger canids, the decline in large prey, and/or concurrent increases in aridity during this interval. A dramatic increase in scavenging of forested prey (e.g., deer) during the past century stands out as significantly distinct from the dietary niches occupied over the past 50,000 years—implying dramatic impacts of human behavior on coyotes, a recent shift in their ecological role, and the highly adaptable nature of these carnivores.

Paleoecology of the Plio-Pleistocene of Queensland: Ecological Shifts Evidenced From Fauna at the Darling Downs

The continent of Australia is currently warming approximately thirty-five percent faster than the rest of the globe, with the warmest year on record coinciding with the most extreme bush fires. While effects of ongoing climate change are apparent over the past century, Australia has experienced pronounced aridification since the Miocene/Pliocene, transitioning from tropical forests to more open habitats. To better contextualize on-going climate change, we assess the ecology and paleobiology of mammalian faunas in Australia from the Pliocene to the Present in the Darling Downs region of Queensland Australia. Via the analysis of stable isotopes from tooth enamel and dental microwear texture analysis of the chewing surfaces of teeth, we clarify the ecology and paleobiology of medium to large marsupials from the Pliocene Chinchilla Sands and Pleistocene Eastern Darling Downs faunas. By comparing these ancient marsupial mammal communities to extant marsupial mammals that inhabit these regions today, we further demonstrate that the most dramatic changes between past ecosystems are clearly between those of the Present and the Plio-Pleistocene—indicated that the Darling Downs region of today is disparate as compared to the past. Most notably, Macropus giganteus consumes vegetation that is ~5.6‰ higher in δ13C values today than during the past, indicating feeding in a significantly more open landscape. The Pliocene and Pleistocene of the Darling Downs are instead dominated by mixed-feeding and browsing taxa, with several taxa exhibiting diets disparate from modern analogues (e.g., an abundance of C4 browsers). Collectively, these deep-time temporal comparisons are a clear example of how ecological communities observed today do not represent the full range of ecological niches occupied in the past and highlight the dramatic climate-departures experienced today.

Dental wear and oral pathology among sex determined Early Bronze-Age children from Franzhausen I, Lower Austria.

The physical properties of diet and oral health throughout childhood play an important role in the development of human dentition, and differed greatly before the industrial revolution. In this study we examined dental wear and oral pathology in a sample of children from the Early Bronze-Age to investigate the physical and mechanical properties of childhood diet and related oral health. We explore cross-sectional age and sex-based variation of children in the sample. The analysis was carried out on the dentitions of 75 children, 978 teeth, excavated from the Early Bronze-Age cemetery Franzhausen I in Lower Austria. Presence of dental caries and calculus was recorded. Dental wear was measured using dentine exposure, occlusal topography, and dental microwear texture analysis. Sex determination was carried out using amelogenin peptide analysis. Caries were found in only 4 individuals (crude prevalence rate-5%, 95% CI 1% to 13%), affecting only 5 teeth (true prevalence rate-less than 1%). Dentine exposure was observed in over 70% of deciduous molars and dental wear measurements indicate a comparatively strong dental wear accumulation especially, among younger children, when compared to modern-day and later pre-industrial populations. Microwear textures presented a high complexity (Asfc > 2)/low anisotropy (epLsar < 1) profile, especially in older children. Differences between male and female children were not generally significant but increased dentine exposure was observed in the lower molars of younger female children. Our results suggest that the Early Bronze-Age children at Franzhausen I consumed a non-cariogenic diet, more abrasive and inclusive of harder/polyhedral foodstuffs than present-day children and some later Medieval children. Differences in dental wear accumulation were observed between children within the population, but with minimal variation between the sexes mostly occurring among younger children.

A long-term perspective on Neanderthal environment and subsistence: Insights from the dental microwear texture analysis of hunted ungulates at Combe-Grenal (Dordogne, France).

Large bovids and cervids constituted major components of the European Middle Palaeolithic faunas and hence a key resource for Neanderthal populations. In paleoenvironmental reconstructions, red deer (Cervus elaphus) occurrence is classically considered as a tree-cover indicator while Bovinae (Bison priscus and Bos primigenius) and reindeer (Rangifer tarandus) occurrences are typically associated with open landscapes. However, insights into the ecology of extant ungulate populations show a more complex reality. Exploring the diet of past ungulates allows to better comprehend the hunting strategies of Palaeolithic populations and to reconstruct the modifications through time of past landscapes. By reflecting what animals have eaten during the last days or weeks of their life, dental microwear textures of herbivores link a population and its environment. Here we analyzed, via Dental Microwear Texture Analysis (DMTA), the diet of 50 Bos/Bison, 202 R. tarandus and 116 C. elaphus preyed upon by the Neanderthals that occupied Combe-Grenal rock-shelter, one of the most important Mousterian archaeo-sequences in southwestern France considering its long stratigraphy, abundance of faunal remains and the variations perceptible in Palaeolithic material culture. Grazers and mixed-feeders are the most represented dietary categories among Combe-Grenal's guild of herbivores, highlighting the availability, along the sequence, of open landscapes. The absence of clear changes in the use of plant resources by hunted ungulates through time, even though palaeoenvironmental changes were well-documented by previous studies along the sequence, is interpreted as resulting from the hunting of non-randomly selected prey by Neanderthals, preferentially in open environments. Thus, these results provide further insight into the hunting strategies of Neanderthals and modify our perception of potential links between subsistence and material culture. Combe-Grenal hunters "stayed in the open" through millennia, and were not forced to switch to hunting tactics and material technology adapted to close encounters in forested environments.

Behavioral strategies of prehistoric and historic children from dental microwear texture analysis

IntroductionReconstructing the dietary and behavioral strategies of our hominin ancestors is crucial to understanding their evolution, adaptation, and overall way of life. Teeth in general, and dental microwear specifically, provide a means to examine these strategies, with posterior teeth well positioned to tell us about diet, and anterior teeth helping us examine non-dietary tooth-use behaviors. Past research predominantly focused on strategies of adult individuals, leaving us to wonder the role children may have played in the community at large. Here we begin to address this by analyzing prehistoric and historic children through dental microwear texture analysis of deciduous anterior teeth.Materials and MethodsFour sample groups were used: Neandertals (N = 8), early modern humans (N = 14), historic Egyptians from Amarna (N = 19) and historic high-Arctic Inuit from Point Hope, Alaska (N = 6). Anterior deciduous teeth were carefully cleaned, molded, and cast with high-resolution materials. Labial surfaces were scanned for dental microwear textures using two white-light confocal microscopes at the University of Arkansas, and a soft filter applied to facilitate data comparisons.Results and DiscussionResults show that dental microwear texture analysis successfully differentiated the samples by all texture variables examined (anisotropy, complexity, scale of maximum complexity, and two variants of heterogeneity). Interestingly, the Neandertal and Point Hope children had similar mean values across all the texture variables, and both groups were significantly different from the Amarna, Egyptian children. These differences suggest diversity in abrasive load exposure and participation in non-dietary anterior tooth-use behaviors. Further analyses and an expanded sample size will help to strengthen the data presented here, but our results show that some prehistoric and historic children took part in similar behaviors as their adult counterparts.

Multi-proxy dentition analyses reveal niche partitioning between sympatric herbivorous dinosaurs

Dentitions of the sympatric herbivorous dinosaurs Hungarosaurus (Ankylosauria, Nodosauridae) and Mochlodon (Ornithopoda, Rhabdodontidae) (Santonian, Hungary) were analysed to investigate their dietary ecology, using several complementary methods—orientation patch count, tooth replacement rate, macrowear, tooth wear rate, traditional microwear, and dental microwear texture analysis (DMTA). Tooth formation time is similar in Hungarosaurus and Mochlodon, and traditional and DMTA microwear features suggest low-browsing habits for both taxa, consistent with their inferred stances and body sizes. However, Mochlodon possesses a novel adaptation for increasing dental durability: the dentine on the working side of the crown is double the thickness of that on the balancing side. Moreover, crown morphology, enamel thickness, macrowear orientation, and wear rate differ greatly between the two taxa. Consequently, these sympatric herbivores probably exploited plants of different toughness, implying dietary selectivity and niche partitioning. Hungarosaurus is inferred to have eaten softer vegetation, whereas Mochlodon likely fed on tougher material. Compared to the much heavier, quadrupedal Hungarosaurus, the bipedal Mochlodon wore down more than twice as much of its crown volume during the functional life of the tooth. This heavy tooth wear might correlate with more intensive food processing and, in turn, could reflect differences in the metabolic requirements of these animals.

Interpreting spatially explicit variation in dietary proxies through species distribution modeling reveals foraging preferences of mammoth (Mammuthus) and American mastodon (Mammut americanum)

IntroductionThe end Pleistocene was a time of considerable ecological upheaval. Recent work has explored the megafauna extinction’s role in altering ecosystem processes. Analyses of functional traits withing communities reveal hidden consequences of the megafauna extinction beyond declines in taxonomic diversity. Functional diversity analyses offer new insight into our understanding of past ecosystems and may even inform future rewilding efforts. However, the utility of functional diversity may be hampered by the use of discrete, taxon-level functional traits, such as dietary categories, that mask variation in functional diversity over space and time.MethodsWe present an approach in which species distribution modeling, in Maxent, provides context for interpreting variation in two widely used proxies for diet among fossil taxa: stable isotope analysis and dental microwear texture analysis. We apply this approach to two ecologically distinct taxa, the American mastodon (Mammut americanum) and mammoths (Mammuthus) and investigate their resource use over space and time from the last glacial maximum to the end Pleistocene (25–11.7 thousand years before present).ResultsMammoth dietary behavior varies by context across their geographic distribution, despite possessing evolutionary adaptations that facilitate grazing. Mammoths exhibit a preference for grazing where species distribution modeling predicts the highest likelihood of occurrence but engage in more mixed-feeding outside of core likelihood areas. In contrast, dietary preferences for mastodon are less resolved and our analyses were unable to identify significant differences in diet across their distribution.DiscussionThe ecological roles of some species are context specific and need to be critically evaluated when planning for management of reintroductions or introducing novel species to restore lost ecological function.

A workflow for quality control in surface texture analysis applied to teeth and tools

Quantification and automation represent important methodological developments in dental microwear analysis and in artifact microwear (use-wear) analysis in order to address the issues of subjectivity and reproducibility of the traditional methods, increase discrimination power, and improve pattern recognition. However, automatic and quantitative methods (dental microwear texture and quantitative artifact microwear analyses) require high-quality data to work with. Surface data acquired with confocal microscopy can reach incredible levels of accuracy and resolution; yet, they are not without issues. In this paper, in an approach similar to quality control in industry, I propose a good-practice workflow for controlling the quality of the acquired and processed 3D data (height maps). I also suggest tools to deal with some of the issues commonly encountered. This workflow should be applied routinely to every height map after acquisition and processing, so that only high-quality height maps are analyzed. In turn, the systematic quality control of the 3D data improves the robustness of the quantitative results and of their interpretations.

First application of dental microwear texture analysis to infer theropod feeding ecology

AbstractTheropods were the dominating apex predators in most Jurassic and Cretaceous terrestrial ecosystems. Their feeding ecology has always been of great interest, and new computational methods have yielded more detailed reconstructions of differences in theropod feeding behaviour. Many approaches, however, rely on well‐preserved skulls. Dental microwear texture (DMT) analysis is potentially applicable to isolated teeth, and here employed for the first time to investigate dietary ecology of theropods. In particular, we test whether tyrannosaurids show DMT associated with more hard‐object feeding than compared to Allosaurus; this would be a sign for higher levels of osteophagy, as has often been suggested. We find no significant difference in complexity and roughness of enamel surfaces between Allosaurus and tyrannosaurids, which conflicts with inferences of more frequent osteophagic behaviour in Tyrannosaurus as compared to other theropods. Orientation of wear features reveals a more pronounced bi‐directional puncture‐and‐pull feeding mode in Allosaurus than in tyrannosaurids. Our results further indicate ontogenetic niche shift in theropods and crocodylians, based on significantly larger height parameters in juvenile theropods which might indicate frequent scavenging, resulting in more bone–tooth contact during feeding. Overall, DMT is found to be very similar between theropods and extant large, broad‐snouted crocodylians and shows great similarity in feeding ecology of theropod apex predators throughout the Jurassic and Cretaceous.

Controlled feeding experiments with juvenile alligators reveal microscopic dental wear texture patterns associated with hard-object feeding

Dental wear analyses are classically applied to mammals because they have evolved heterodont dentitions for sophisticated mastication. Recently, several studies have shown a correlation between pre-assigned and analytically inferred diet preferences in extant reptiles through dental microwear texture analysis (DMTA), a method using quantitative assessment of microscopic wear marks to reconstruct the diet material properties. The first tentative applications of DMTA to extinct reptiles have followed. However, for large and small mammals, microwear analyses have undergone a long time of ground-truthing through direct feeding observations, stomach content analyses, and feeding experiments. Such data are currently lacking for reptiles, but are necessary to further extend DMTA, especially to Archosauria, as the application to dinosaurs could be of great interest to the scientific community. We herein present data from a pilot feeding experiment with five juvenile American alligators (Alligator mississippiensis). Each individual received a diet of assumed different hardness for ~4 months: crocodylian pellets (control), sardines, quails, rats, or crawfish. All individuals initially received the same pellet diet, and we found them to show similar dental microwear texture patterns before they were switched to their designated experimental diet. From the first feeding bout on, dental microwear textures differed across the diets. The crawfish-feeder showed consistently higher surface complexity, followed by the rat-feeder. Quail- and fish-feeding resulted in similar wear signatures, with low complexity. Fast tooth replacement and selective tooth use likely affected microwear formation, but we were able to detect a general hard (crawfish and rat) versus soft (quail and fish) DMTA signature. Such patterns can support the identification of hard-object feeding in the fossil record.

Accuracy of dental microwear impressions by physical properties of silicone materials

Dental microwear analysis is an oft-used paleodietary estimation method, and the impression molds or resin casts are often analyzed rather than the original tooth surfaces. A choice of silicone products for dental impressions is crucial because the quality of microwear data is affected by the impression accuracy of the molds. For this reason, microwear researchers have heavily depended on a few commercial products such as “President” (Coltène/Whaledent AG, Switzerland) to avoid analytical errors caused using different silicone materials. Considering that the production business might be terminated, however, heavy reliance on specific products could be a potential weakness in the field. In this study, we aimed at identifying specific indexes of physical properties of silicone materials with satisfactory accuracy. For this purpose, we measured dynamic viscoelasticity and shrinkage rates of various silicone compounds, including the standard impression material President and other eight affordable dental silicones. We scanned both original tooth surface and dental impression molds with a confocal laser microscope and conducted dental microwear texture analysis (DMTA) to quantitatively compare the scanned surfaces. The results showed relationships between the material properties of silicones and impression accuracy, indicating that the materials that cured slowly and began to shrink relatively early in the hardening process were less accurate. Some of these dental impression molds showed blurred surfaces, implying that molds were peeled off from the tooth surface at the microscopic level, as the shrinkage speed might exceed the curing speed. The following indices provided in the product information were found to be helpful in the search for substitutes: (1) medium viscosity, (2) short curing time after mixing (5–6 min), and (3) delayed change in shrinkage.

Dental mesowear and microwear for the dietary reconstruction of Quaternary Southeast Asian serows and gorals

Serows and gorals (Bovidae, Caprinae) are emblematic antelopes distributed in Southeast Asia. They all are nearly threaten or vulnerable species nowadays despite having a more widespread distribution during the Pleistocene. Fossils of three native caprine species, i.e., a Sumatran serowCapricornis sumatraensis, Chinese goralNaemorhedus griseus, and Himalayan goralNaemorhedus goral, were recovered from four Pleistocene paleontological and archeological sites in Thailand, namely Pha Bong, Khok Sung, Tham Wiman Nakin, and Tham Lod Rockshelter. To investigate dietary changes of these Southeast Asian serows and gorals through the Quaternary, differences in feeding habits and habitat preferences between the Pleistocene and extant populations were examined using the hypsodonty index (HI) together with the mesowear II method and the dental microwear texture analysis (DMTA). The HI and mesowear-II results showed that Pleistocene and extant caprines were mixed feeders. For the Pleistocene caprine populations, the DMTA results suggested more browsing signals forC. sumatraensisthan bothNaemorhedusspecies that were mixed feeders similar to their extant populations. The DMTA demonstrated a considerable dietary overlap among the Pleistocene sympatric caprine populations. The dental microwear results also revealed that the extantC. sumatraensisis a leaf-dominant browser, while the extantN. griseuspossibly feeds on seeds or tough food items. These data combined with previous stable carbon isotope analyses reinforce the idea that the restricted ranges of habitats for these extant serow and goral populations have possibly been driven by the Holocene climatic and environmental changes as well as the negative effects of human activities.

The Ice Age diet of the La Quina 5 Neandertal of southwest France

The La Quina 5 Neandertal individual, dated to late Marine Isotope Stage (MIS) 4 or early MIS 3, lived during a particularly cold and arid Ice Age interval, hunting mostly reindeer in open steppe habitats. Stable isotopes indicate the importance of hunted resources for Neandertals, although evidence of plant use also has been discovered. To address the plant food signature in the diet of La Quina 5, we marshal multiple methods, including dental microwear texture analysis (DMTA) and plant microremains analysis. For the DMTA, La Quina 5 is compared to Neandertals from MIS 5 – MIS 3, including Malarnaud, Spy I, Kůlna 1, Švédův stůl 1, and several individuals from Hortus cave (n=5), Krapina (n=19) and Vindija (n=4), as well as human foragers, farmers and pastoralists (n=150). La Quina 5 presents a low value for anisotropy implying the use of heterogeneous masticatory regimes like those characterizing foragers of the Americas. La Quina 5 also has a low complexity value indicating a plant-poor diet, and may have relied significantly on hunted resources perhaps necessary in the cold glacial interval of lower temperatures during Heinrich Stadial 6. Nevertheless, plant microremains are preserved in the dental calculus, including starch grains from grass seeds and plant underground storage organs, demonstrating the importance of plant foods in Paleolithic diets even if temporally or spatially dispersed.

Dental microwear texture analysis correlations in guinea pigs (Cavia porcellus) and sheep (Ovis aries) suggest that dental microwear texture signal consistency is species-specific

Dental microwear texture (DMT) analysis is used to differentiate abrasive dental wear patterns in many species fed different diets. Because DMT parameters all describe the same surface, they are expected to correlate with each other distinctively. Here, we explore the data range of, and correlations between, DMT parameters to increase the understanding of how this group of proxies records wear within and across species. The analysis was based on subsets of previously published DMT analyses in guinea pigs, sheep, and rabbits fed either a natural whole plant diet (lucerne, grass, bamboo) or pelleted diets with or without added quartz abrasives (guinea pigs and rabbits: up to 45 days, sheep: 17 months). The normalized DMT parameter range (P4: 0.69 ± 0.25; M2: 0.83 ± 0.16) and correlation coefficients (P4: 0.50 ± 0.31; M2: 0.63 ± 0.31) increased along the tooth row in guinea pigs, suggesting that strong correlations may be partially explained by data range. A comparison between sheep and guinea pigs revealed a higher DMT data range in sheep (0.93 ± 0.16; guinea pigs: 0.47 ± 0.29), but this did not translate into more substantial correlation coefficients (sheep: 0.35 ± 0.28; guinea pigs: 0.55 ± 0.32). Adding rabbits to an interspecies comparison of low abrasive dental wear (pelleted lucerne diet), the softer enamel of the hypselodont species showed a smaller data range for DMT parameters (guinea pigs 0.49 ± 0.32, rabbit 0.19 ± 0.18, sheep 0.78 ± 0.22) but again slightly higher correlations coefficients compared to the hypsodont teeth (guinea pigs 0.55 ± 0.31, rabbits 0.56 ± 0.30, sheep 0.42 ± 0.27). The findings suggest that the softer enamel of fast-replaced ever-growing hypselodont cheek teeth shows a greater inherent wear trace consistency, whereas the harder enamel of permanent and non-replaced enamel of hypsodont ruminant teeth records less coherent wear patterns. Because consistent diets were used across taxa, this effect cannot be ascribed to the random overwriting of individual wear traces on the more durable hypsodont teeth. This matches literature reports on reduced DMT pattern consistency on harder materials; possibly, individual wear events become more random in nature on harder material. Given the species-specific differences in enamel characteristics, the findings suggest a certain species-specificity of DMT patterns.