Sr/Ca ratios indicate frugivory versus folivory in primates: a case study using handheld XRF in Kibale National Park, Uganda.

Researchers often use trace element concentrations, including strontium-calcium ratios (Sr/Ca), to reconstruct paleodiets. While most commonly used as a proxy for meat consumption, a more appropriate application may be to differentiate frugivory from folivory. Sr/Ca ratios in animal tissue reflect the Sr/Ca ratios of the highest calcium components of that animal's diet. Because plants have much higher concentrations of calcium than meat, meat consumption signals are often overwhelmed by the variation in Sr/Ca ratios coming from different plant parts. This study uses faunal and plant data from Kibale National Park, a protected forest in southwestern Uganda home to numerous primate species (for example, common chimpanzees and baboons), to assess the reliability of Sr/Ca ratios to differentiate between primate dietary groups. We find that leaves consistently have higher strontium and calcium concentrations than fruits and that this is mirrored in higher Sr/Ca ratios in folivorous primates compared to frugivorous primates. Plant species differ widely in both their overall Sr/Ca ratios and the differences between their fruit and leaf Sr/Ca ratios, but this variation does not overwhelm the dietary signal separating frugivores and folivores. Furthermore, this research demonstrates that non-destructive and portable X-ray florescence (XRF) methods are an effective means of gathering Sr/Ca data from plant and faunal material, increasing the opportunities to apply such methods to fossil material in the future.

Reconstructing herbivore diets: a multivariate statistical approach to interpreting amino acid nitrogen isotope values.

Recent studies have demonstrated that there exists significant variability in amino acid (AA) δ15N values of terrestrial plants, discriminating among plant types (i.e., legume seeds, grasses, tree leaves) as well as tissues of the same plant. For the first time, we investigate the potential of the spacing between the δ15N values of different AAs to differentiate between plant types and thus elucidate their relative importance in herbivore diet. Using principal component analysis, we show that it is possible to distinguish among five plant categories-cereal grains, rachis, legume seeds, herbaceous plants, and woody plants-whose consumption has different implications for understanding herbivore ecology and management practices. Furthermore, we were able to correctly classify the herbaceous plant diet of modern cattle using AA δ15N values of their tooth dentine adjusted for trophic enrichment. The AA δ15N patterns of wild and domestic herbivores from archaeological sites seem to be consistent with diets comprised predominantly of herbaceous plants, but there is variation in AA δ15N values among individuals that may reflect differing inputs of other plant types. The variation in AA δ15N values does not necessarily reflect the variation in herbivore bulk collagen δ13C and δ15N values, indicating that AA δ15N values have the potential to provide additional insights into plant dietary sources compared to bulk tissue isotope values alone. Future work should focus on defining trophic enrichment factors for a wider range of terrestrial herbivores and expanding libraries of primary producer AA δ15N values.

Shape, size, and quantity of ingested external abrasives influence dental microwear texture formation in guinea pigs.

Food processing wears down teeth, thus affecting tooth functionality and evolutionary success. Other than intrinsic silica phytoliths, extrinsic mineral dust/grit adhering to plants causes tooth wear in mammalian herbivores. Dental microwear texture analysis (DMTA) is widely applied to infer diet from microscopic dental wear traces. The relationship between external abrasives and dental microwear texture (DMT) formation remains elusive. Feeding experiments with sheep have shown negligible effects of dust-laden grass and browse, suggesting that intrinsic properties of plants are more important. Here, we explore the effect of clay- to sand-sized mineral abrasives (quartz, volcanic ash, loess, kaolin) on DMT in a controlled feeding experiment with guinea pigs. By adding 1, 4, 5, or 8% mineral abrasives to a pelleted base diet, we test for the effect of particle size, shape, and amount on DMT. Wear by fine-grained quartz (>5/<50 µm), loess, and kaolin is not significantly different from the abrasive-free control diet. Fine silt-sized quartz (∼5 µm) results in higher surface anisotropy and lower roughness (polishing effect). Coarse-grained volcanic ash leads to significantly higher complexity, while fine sands (130 to 166 µm) result in significantly higher roughness. Complexity and roughness values exceed those from feeding experiments with guinea pigs who received plants with different phytolith content. Our results highlight that large (>95-µm) external silicate abrasives lead to distinct microscopic wear with higher roughness and complexity than caused by mineral abrasive-free herbivorous diets. Hence, high loads of mineral dust and grit in natural diets might be identified by DMTA, also in the fossil record.

Multiproxy isotopic analyses of human skeletal material from Rapa Nui: Evaluating the evidence from carbonates, bulk collagen, and amino acids.

OBJECTIVES: Stable isotope ratio analysis of bulk bone collagen dominates research into past diet; however, bone carbonate and compound specific isotope analyses (CSIA) of amino acids provide alternative, yet complementary, lines of evidence toward that same research goal. Together they inform on different aspects of diet, allowing greater certainty in reconstructions. Here we present new data on carbonate isotopes for Rapa Nui and reevaluate prehistoric diet in the context of these new and previously published bulk collagen and CSIA data. MATERIALS AND METHODS: We analyzed carbon isotopes in bone carbonate from 28 prehistoric human teeth from Rapa Nui. These represent a subset of material examined previously for carbon and nitrogen isotope ratios in bulk collagen. We then reevaluate prehistoric diet in light of these and other published data. In addition, we analyzed carbon and nitrogen isotope ratios in 28 modern plant specimens from Rapa Nui to better approximate the isotopic value of the terrestrial endmember. RESULTS: Bulk data suggest a predominantly terrestrial diet, with the amount of marine sources incorporated varying though time. While previously argued to reveal greater amounts of marine consumption, reanalysis of recently published CSIA data suggests this result may relate to the proportion of carbon assimilated rather than consumed. Utilizing models incorporating concentration dependence for estimating dietary proportions results in much lower estimates of marine consumption, in line with findings of the bulk data. DISCUSSION: While these data indicate a larger focus on terrestrial resources, limitations in all forms of analysis make it difficult to determine exact dietary contributions in this mixed system. Better understanding of the complex physiological processes governing isotopic routing and fractionation, and knowledge of appropriate isotopic endmember values are needed to advance this research.

New model to explain tooth wear with implications for microwear formation and diet reconstruction.

Paleoanthropologists and vertebrate paleontologists have for decades debated the etiology of tooth wear and its implications for understanding the diets of human ancestors and other extinct mammals. The debate has recently taken a twist, calling into question the efficacy of dental microwear to reveal diet. Some argue that endogenous abrasives in plants (opal phytoliths) are too soft to abrade enamel, and that tooth wear is caused principally by exogenous quartz grit on food. If so, variation in microwear among fossil species may relate more to habitat than diet. This has important implications for paleobiologists because microwear is a common proxy for diets of fossil species. Here we reexamine the notion that particles softer than enamel (e.g., silica phytoliths) do not wear teeth. We scored human enamel using a microfabrication instrument fitted with soft particles (aluminum and brass spheres) and an atomic force microscope (AFM) fitted with silica particles under fixed normal loads, sliding speeds, and spans. Resulting damage was measured by AFM, and morphology and composition of debris were determined by scanning electron microscopy with energy-dispersive X-ray spectroscopy. Enamel chips removed from the surface demonstrate that softer particles produce wear under conditions mimicking chewing. Previous models posited that such particles rub enamel and create ridges alongside indentations without tissue removal. We propose that although these models hold for deformable metal surfaces, enamel works differently. Hydroxyapatite crystallites are "glued" together by proteins, and tissue removal requires only that contact pressure be sufficient to break the bonds holding enamel together.

Alternative prey use affects helminth parasite infections in grey wolves.

Predators affect prey populations not only through direct predation, but also by acting as definitive hosts for their parasites and completing parasite life cycles. Understanding the affects of parasitism on prey population dynamics requires knowing how their predators' parasite community is affected by diet and prey availability. Ungulates, such as moose (Alces americanus) and white-tailed deer (Odocoileus virginianus), are often important prey for wolves (Canis lupus), but wolves also consume a variety of alternative prey, including beaver (Castor canadensis) and snowshoe hare (Lepus americanus). The use of alternative prey, which may host different or fewer parasites than ungulates, could potentially reduce overall abundance of ungulate parasites within the ecosystem, benefiting both wolves and ungulate hosts. We examined parasites in wolf carcasses from eastern Manitoba and estimated wolf diet using stable isotope analysis. Taeniidae cestodes were present in most wolves (75%), reflecting a diet primarily comprised of ungulates, but nematodes were unexpectedly rare. Cestode abundance was negatively related to the wolf's δ(13) C value, indicating diet affects parasite abundance. Wolves that consumed a higher proportion of beaver and caribou (Rangifer tarandus), estimated using Bayesian mixing models, had lower cestode abundance, suggesting the use of these alternative prey can reduce parasite loads. Long-term consumption of beavers may lower the abundance of adult parasites in wolves, eventually lowering parasite density in the region and ultimately benefiting ungulates that serve as intermediate hosts. Thus, alternative prey can affect both predator-prey and host-parasite interactions and potentially affect food web dynamics.

Stable isotope study on ancient populations of central sudan: Insights on their diet and environment.

OBJECTIVES: A contribution to the knowledge of the economy and the environmental surroundings of the populations living along the Nile valley in three different periods. MATERIALS AND METHODS: This study reports stable isotope analyses on apatite bone samples of 139 humans, 48 mammals, and 43 fish from the Al Khiday archaeological sites in Sudan. The bones belong to four archaeological periods: pre-Mesolithic, Mesolithic, Neolithic, and Meroitic. Data were processed statistically. RESULTS: A significant difference exists between the pre-Mesolithic and Mesolithic mean δ(18) Ow value and the mean of the modern Nile. The mean δ(18) Ow values for the Neolithic humans and bovids are very similar (+1.5‰ ±4‰, and -2‰, respectively) and more positive than the mean values of Mesolithic mammals and Pre-Mesolithic humans. The water ingested by Meroitic humans (+7‰ ± 2.5‰) is enriched in (18) O in respect to the water ingested by the Neolithic population. There is a separation in the δ(13) Cdiet values between the pre-Mesolithic humans (-14‰ ± 1‰) and Mesolithic mammals (-12‰ ± 2‰) group and the Neolithic humans (-18‰ ± 1‰), Meroitic humans (-19‰ ±1‰), Neolithic mammals (-21‰), and the modern (mean δ(13) Cdiet = -19‰ ±2‰) mammal group. DISCUSSION: The climate became warmer and more arid from the pre-Mesolithic/Mesolithic to the Meroitic period. The environmental conditions influenced the strategies of subsistence and, in particular, the changes occurring from the pre-Mesolithic to the Neolithic can be considered contemporaneous to the transition from hunting-gathering-fishing to cultivation-herding. Am J Phys Anthropol 160:498-518, 2016. © 2016 Wiley Periodicals, Inc.

Technical note: An in vitro study of dental microwear formation using the BITE Master II chewing machine.

Dental microwear has been used for decades to reconstruct the diets of fossil hominins and bioarchaeological populations. The basic theory has been that hard-brittle foods (e.g., nuts, bone) require crushing and leave pits as they are pressed between opposing cheek-tooth surfaces, whereas soft-tough foods (e.g., grass blades, meat) require shearing and leave scratches as they are dragged along opposing surfaces that slide past one another. However, recent studies have called into question the efficacy of microwear as an indicator of diet. One issue has been the limited number of in vitro studies providing empirical evidence for associations between microwear pattern and chewing behavior. We here describe a new study using a chewing simulator, the BITE Master II, to examine the effects of angle of approach between opposing teeth and food consistency on microwear surface texture. Results indicate that opposing teeth that approach one another: 1) perpendicular to the occlusal plane (crushing) result in pits; 2) parallel to the occlusal plane (shearing) result in striations in the direction of movement; and 3) oblique to the occlusal plane (45°) result in both striations and pits. Results further suggest that different food types and abrasive loads affect the propensity to accumulate microwear features independent of feature shapes.

Technical Note: Calcium and carbon stable isotope ratios as paleodietary indicators.

Calcium stable isotope ratios are hypothesized to vary as a function of trophic level. This premise raises the possibility of using calcium stable isotope ratios to study the dietary behaviors of fossil taxa and to test competing hypotheses on the adaptive origins of euprimates. To explore this concept, we measured the stable isotope composition of contemporary mammals in northern Borneo and northwestern Costa Rica, two communities with functional or phylogenetic relevance to primate origins. We found that bone collagen δ(13) C and δ(15) N values could differentiate trophic levels in each assemblage, a result that justifies the use of these systems to test the predicted inverse relationship between bioapatite δ(13) C and δ(44) Ca values. As expected, taxonomic carnivores (felids) showed a combination of high δ(13) C and low δ(44) Ca values; however, the δ(44) Ca values of other faunivores were indistinguishable from those of primary consumers. We suggest that the trophic insensitivity of most bioapatite δ(44) Ca values is attributable to the negligible calcium content of arthropod prey. Although the present results are inconclusive, the tandem analysis of δ(44) Ca and δ(13) C values in fossils continues to hold promise for informing paleodietary studies and we highlight this potential by drawing attention to the stable isotope composition of the Early Eocene primate Cantius.

C4 -consumers in southern Europe: the case of Friuli V.G. (NE-Italy) during early and central Middle Ages.

Isotope variations were studied in necropolises of the early (6th to 7th century CE) and central (10th to 11th century CE) medieval period located in Fruili-Venezia Giulia (Northeastern Italy). The two periods each shortly followed two great barbarian invasions that changed the politics and economy of Italy: the arrivals of Langobards in 578 CE and the Hungarian incursions from the end of the 9th to the first half of the 10th century. These events had a tragic effect on the economy of Friuli-Venezia Giulia: severe depopulation and the partial abandonment of the countryside with fall of agricultural production.

Mandible microwear texture analysis of crickets raised on diets of different abrasiveness reveals universality of diet-induced wear.

Animals have evolved diverse comminuting tools. While vertebrates possess mineralized teeth, insect mandibles often bear metal-inclusion-hardened serrated cusps. Microscopic dental enamel wear (microwear) is known to be caused by contact with ingesta. To test if insect mandible microwear is also diet-dependent, we kept newly moulted adult two-spotted crickets (Gryllus bimaculatus) for four weeks on alfalfa-based rodent pellets with and without added mineral abrasives (loess, quartz, volcanic ash). Six crickets per diet were examined after 1, 3, 7, 14, 21 and 28 days. All diets induced progressive mandible wear, affecting specific locations along the distal tooth cusps differently. The depth of furrows increased on most abrasive-containing diets until day 21, while wear mark complexity increased from day 1 to 3 and 14 to 21. After 28 days, these parameter values for large volcanic ash and large quartz diets significantly exceeded those for the control diet. These results are comparable to observations from guinea pig feeding experiments with the same diets. Cricket mandible wear was affected by all abrasives. Notably, large volcanic ash and large quartz induced the deepest, most complex lesions, akin to observations in guinea pigs. This suggests a universal wear process, supporting that microwear analyses are suitable for inferring invertebrate diets.

Lipid Extraction and Sample Preservation Techniques for Stable Isotope Analysis and Ecological Assays.

Lipid extraction is an important component of many ecological and ecotoxicological measurements. For instance, percent lipid is often used as a measure of body condition, under the assumption that those individuals with higher lipid reserves are healthier. Likewise, lipids are depleted in 13C compared with protein, and it is consequently a routine to remove lipids prior to measuring carbon isotopes in ecological studies so that variation in lipid content does not obscure variation in diet. We provide detailed methods for two different protocols for lipid extraction: Soxhlet apparatus and manual distillation. We also provide methods for polar and non-polar solvents. Neutral (non-polar) solvents remove some lipids but few non-lipid compounds whereas polar solvents remove not only most lipids but also many non-lipid compounds. We discuss each of the methods and provide guidelines for best practices. We recommend that for stable isotope analysis, researchers test for a relationship between the change in the carbon stable isotope ratio and the amount of lipid extracted to see if the degree of extraction has an impact on isotope ratios. Stable isotope analysis is widely used by ecologists, and we provide a detailed methodology that minimizes known biases.

Nutritional reconstruction in an early modern population: Searching for a relationship between dental microwear and bone element composition.

BACKGROUND: Observing the microwear patterns of the dental crowns enamel surface can provide information on the ingredients and structure of the food consumed, but also on eating habits and lifestyle. Major role in reconstructing the diet and lifestyle of past populations is played by the analysis of alkaline earth metals, such as strontium, barium, zinc and calcium. Ba and Sr are indicators of the consumption of vegetables, plants (cereals and legumes) and marine organisms. This study aims to assess dietary diversity and identify its components based on microscopic techniques and chemical analyses of material from early modern archaeological sites in Wroclaw, Poland. METHODS: The material consisted of 36 permanent molars and the intrasternal parts of 122 first ribs, collected from 6 Wroclaw early modern cemeteries. Tooth microwear was evaluated on Scanning electron microscopy images, with Microwear 4.02 software. Bone chemical composition (Ca, P, Ba, Sr content) was evaluated with mass spectrometry. RESULTS: Most lines were present on the teeth from St. Mary Magdalene Cemetery, with the lowest average number of lines observed on the teeth from St. Barbara Cemetery. The Ca/P ratios calculated for different sites formed two clusters that allows to distinguish two groups of archaeological sites with different bone preservation status. Number of differences in Ba/Sr, Sr/Ca, Ba/Ca ratios was found between disctinct archaeological sites. A number of correlations were found between the concentration of the chemical elements, but no statistically significant correlation was found between the microwear characteristics and the proportion of the elements studied. Some strong correlations were found between microwear features and the Ca/P ratio. CONCLUSIONS: the different values of Sr/Ca, Ba/Ca and Ba/Sr ratios indicate different diets in the different communities. The data obtained indicate a mixed diet, with a relatively high proportion of animal products throughout Wroclaw. Conclusions should be treated with caution due to secondary diagenesis. The lack of interdependence between microwear and chemical composition characteristics suggests that the two methods should be considered complementary and not overlapping, as they provide different insights into the diets of past populations. The comparison of microwear between different sites should always take into account secondary diagenesis and the burial environment, as these influence the characteristics of microwear.

Dental wear proxy correlation in a long-term feeding experiment on sheep (Ovis aries).

Dietary reconstruction in vertebrates often relies on dental wear-based proxies. Although these proxies are widely applied, the contributions of physical and mechanical processes leading to meso- and microwear are still unclear. We tested their correlation using sheep (Ovis aries, n = 39) fed diets of varying abrasiveness for 17 months as a model. Volumetric crown tissue loss, mesowear change and dental microwear texture analysis (DMTA) were all applied to the same teeth. We hereby correlate: (i) 46 DMTA parameters with each other, for the maxillary molars (M1, M2, M3), and the second mandibular molar (m2); (ii) 10 mesowear variables to each other and to DMTA for M1, M2, M3 and m2; and (iii) volumetric crown tissue loss to mesowear and DMTA for M2. As expected, many DMTA parameters correlated strongly with each other, supporting the application of reduced parameter sets in future studies. Correlation results showed only few DMTA parameters correlated with volumetric tissue change and even less so with mesowear variables, with no correlation between mesowear and volumetric tissue change. These findings caution against interpreting DMTA and mesowear patterns in terms of actual tissue removal until these dental wear processes can be better understood at microscopic and macroscopic levels.

Elucidating shark diets with DNA metabarcoding from cloacal swabs.

Animal dietary information provides the foundation for understanding trophic relationships, which is essential for ecosystem management. Yet, in marine systems, high-resolution diet reconstruction tools are currently under-developed. This is particularly pertinent for large marine vertebrates, for which direct foraging behaviour is difficult or impossible to observe and, due to their conservation status, the collection of stomach contents at adequate sample sizes is frequently impossible. Consequently, the diets of many groups, such as sharks, have largely remained unresolved. To address this knowledge gap, we applied metabarcoding to prey DNA in faecal residues (fDNA) collected on cotton swabs from the inside of a shark's cloaca. We used a previously published primer set targeting a small section of the 12S rRNA mitochondrial gene to amplify teleost prey species DNA. We tested the utility of this method in a controlled feeding experiment with captive juvenile lemon sharks (Negaprion brevirostris) and on free-ranging juvenile bull sharks (Carcharhinus leucas). In the captive trial, we successfully isolated and correctly identified teleost prey DNA without incurring environmental DNA contamination from the surrounding seawater. In the field, we were able to reconstruct high-resolution teleost dietary information from juvenile C. leucas fDNA that was generally consistent with expectations based on published diet studies of this species. While further investigation is needed to validate the method for larger sharks and other species, it is expected to be broadly applicable to aquatic vertebrates and provides an opportunity to advance our understanding of trophic interactions in marine and freshwater systems.

The history of mesowear: a review.

Published mesowear data was reviewed from the year 2000 to November 2019 (211 publications, 707 species, 1,396 data points). Mesowear is a widely applied tooth wear technique that can be used to infer a herbivore's diet by scoring the height and sharpness of molar tooth cusps with the naked eye. Established as a fast and efficient tool for paleodiet reconstruction, the technique has seen multiple adaptations, simplifications, and extensions since its establishment, which have become complex to follow. The present study reviews all successive changes and adaptations to the mesowear technique in detail, providing a template for the application of each technique to the research question at hand. In addition, the array of species to which mesowear has been applied, along with the equivalent recorded diets have been compiled here in a large dataset. This review provides an insight into the metrics related to mesowear publication since its establishment. The large dataset overviews whether the species to which the various techniques of mesowear are applied are extant or extinct, their phylogenetic classification, their assigned diets and diet stability between studies, as a resource for future research on the topic.

Isotopic Discrimination (δ15N, δ13C) in Captive and Wild Common Murres (Uria aalge) and Atlantic Puffins (Fratercula arctica).

Studying the diet of consumers using stable isotopes provides insight into the foraging ecology of individuals and species. To accurately reconstruct the integrated diet of animals using stable isotope values, we must quantify diet-tissue discrimination factors (DTDFs), or the way in which stable isotopes in prey are incorporated into the tissues of consumers. To quantify DTDFs, controlled experiments are needed, whereby consumers are fed a constant diet. However, relatively few controlled-diet studies have been conducted for seabirds. In this study, captive adult Atlantic puffins (Fratercula arctica) and common murres (Uria aalge) were fed a two-source diet of capelin (Mallotus villosus) and Atlantic silverside (Menidia menidia) to determine the DTDFs for the cellular component of blood and plasma for both δ15N and δ13C. The DTDFs for the cellular component (Δ15N: 2.80±0.28; Δ13C: 1.21±0.22) and plasma (Δ15N: 1.72±1.03; Δ13C: -0.18±0.56) of puffins were similar to those for the cellular component (Δ15N: 2.91±0.18; Δ13C: 1.09±0.23) and plasma (Δ15N: 2.18±0.77; Δ13C: -0.70±0.18) of murres. We reconstructed the diet of wild murres and puffins breeding on the northeastern coast of Newfoundland using previously published DTDFs and estimated DTDFs from our feeding experiment. Reconstructed dietary proportions supported a priori knowledge of diet, although outputs were sensitive to the DTDF used. Despite the similarity of our DTDFs for puffins and murres, along with the similarity of our DTDFs with those of other seabird species, our sensitivity analysis revealed considerable differences among resultant dietary contributions from mixing models, further highlighting the importance of using species- and tissue-specific DTDFs to enhance knowledge in the foraging ecology of seabirds using stable isotopes.

Combining stable isotopes, morphological, and molecular analyses to reconstruct the diet of free-ranging consumers.

Accurate estimates of animal diet composition are essential to untangle complex interactions in food webs. Biomarkers and molecular tools are increasingly used to estimate diet, sometimes alongside traditional dietary tracing methods. Yet only a few empirical studies have compared the outcomes and potential gains of using a combination of these methods, especially using free-ranging animals with distinct foraging preferences.We used stable isotopes, morphological, and molecular analyses to investigate the diet of free-ranging consumers with two distinct diet types, that is, carnivore and omnivore. By combining the three analytical methods to assess the diet of consumers during the same period, we aimed to identify the limits of each method and to assess the potential benefits of their combined use to derive diet estimates.Our results showed that the different methods led to a consistent diet description for carnivores, which have a relatively simple diet mixture, but their outcomes somewhat differed for omnivore, which have a more complex diet. Still, the combined use of morphological and molecular analyses enhanced the diversity of food sources detected compared to the use of a single method independently of diet types. Precision of diet estimates derived from stable isotope analyses was improved by the addition of priors obtained from morphological and molecular diet analyses of the same population.Although we used free-ranging animals without a known diet, our empirical testing of three of the most widely used methods of diet determination highlights the limits of relying over a single approach, especially in systems with few or no a priori information about the foraging habits of consumers. The choice of an appropriate approach of diet description should be a key step when planning dietary studies of free-ranging populations. We recommend using more than one dietary determination methods especially for species with complex diet mixtures.

MicroWeaR: A new R package for dental microwear analysis.

Mastication of dietary items with different mechanical properties leaves distinctive microscopic marks on the surface of tooth enamel. The inspection of such marks (dental microwear analysis) is informative about the dietary habitus in fossil as well as in modern species. Dental microwear analysis relies on the morphology, abundance, direction, and distribution of these microscopic marks. We present a new freely available software implementation, MicroWeaR, that, compared to traditional dental microwear tools, allows more rapid, observer error free, and inexpensive quantification and classification of all the microscopic marks (also including for the first time different subtypes of scars). Classification parameters and graphical rendering of the output are fully settable by the user. MicroWeaR includes functions to (a) sample the marks, (b) classify features into categories as pits or scratches and then into their respective subcategories (large pits, coarse scratches, etc.), (c) generate an output table with summary information, and (d) obtain a visual surface-map where marks are highlighted. We provide a tutorial to reproduce the steps required to perform microwear analysis and to test tool functionalities. Then, we present two case studies to illustrate how MicroWeaR works. The first regards a Miocene great ape obtained from through environmental scanning electron microscope, and other a Pleistocene cervid acquired by a stereomicroscope.

Know your fish: A novel compound-specific isotope approach for tracing wild and farmed salmon.

The rapid expansion of the aquaculture industry with carnivorous fish such as salmon has been accompanied by an equally rapid development in alternative feed ingredients. This has outpaced the ability of prevailing authentication method to trace the diet and origins of salmon products at the retail end. To close this gap, we developed a new profiling tool based on amino acid δ13C fingerprints. With this tool, we discriminated with high-accuracy among wild-caught, organically, and conventionally farmed salmon groups, as well as salmon fed alternative diets such as insects and macroalgae. Substitution of fishmeal with macroalgae was detected at 5% difference level. The δ13C fingerprints of essential amino acids appear particularly well suited for tracing protein sources, and the non-essentials for tracing lipid origins (terrestrial vs. aquatic). In an industry constantly developing new feed proteins and functional additives, our method is a promising tool for tracing salmon and other seafood products.