Dental microwear texture analysis (DMTA) has been widely used in the study of dietary habits and trends of animals, based on the abrasion patterns preserved in dental enamel. Therefore, it is seen as an important tool when it comes to understanding the ecology, niche partitioning, and competition between co-occurring taxa, both extant and extinct. During the Late Jurassic, sauropod dinosaur faunas were quite diverse, with distinct groups inhabiting the same ecosystems. Being the largest mega-herbivores of their ecosystems, competition for resources could have been a determining factor that led to such diversity, making sauropods a good study-group for DMTA. Here we describe the complete process of creating a large DMTA dataset of 119 teeth attributed to most major sauropod groups from the Late Jurassic. We describe in detail the production of dental molds, casts, and the steps taken throughout the measuring process of the three-dimensional surface textures. We also describe the way in which we tested the quality of our data, as well as the taphonomical implications for future studies using the resulting dataset. Not only did our tests confirm the lack of a taphonomic impact on the acquired data but also the comparability of measurements obtained from both molds and original teeth. The end result is the first large DMTA sauropod teeth dataset, consisting of 971 measurements.

Most faunas from the Mesozoic era were dominated by sauropod dinosaurs, the largest terrestrial animals to ever exist. These megaherbivores were remarkably diverse and widely distributed. Here we study three Late Jurassic faunas from the USA, Portugal and Tanzania, each approximately 150 million years old, which are known for their extreme sauropod diversity. Whereas general taxonomic composition was similar in these three faunas, the major clades differed in relative abundance. Moreover, their depositional strata record distinct climatic regimes. Using dental microwear texture analysis, we investigated the impact of these climate regimes and the resulting food availability on the different sauropod taxa. Wear patterns in camarasaurid macronarians show minimal variation across different climate regimes, supporting previous studies suggesting that these animals migrated to follow their preferred climate niche and food source. North American camarasaurids show similar wear patterns to those of Portuguese turiasaurs, another broad-crowned taxon, which did not exist in the Jurassic of North America. By contrast, where camarasaurids and turiasaurs co-occurred in Portugal, their microwear patterns are distinct, suggesting niche differentiation to avoid ecological competition between these two clades. Flagellicaudatan diplodocoids display highly variable wear patterns, indicating limited migration (and therefore seasonal variation in diet), which aligns with observed biogeography patterns in the USA. Early-branching titanosauriforms show highly distinct wear patterns between different climate regimes, which can probably be attributed to different abrasive loads in the respective habitats. Our results demonstrate that dental microwear texture analysis not only records dietary preferences but also reveals behaviour such as competition and migration related to dietary niches in past ecosystems.

Hydrogen and oxygen isotope ratios in proteinaceous tissues have been used for some time in migratory, ecological, and archaeological studies. While the result of isotopic variation in drinking water and diet has been investigated with controlled feeding experiments and studies in the wild, there are few controlled feeding studies that manipulate the diet components and diet type, and this across different taxa. In this experiment, the diet fed to rats, guinea pigs, and quail varied from plant-based to insect-based and meat-based pelleted diets. We report the diet to tissue offsets for δ2H (denoted Δδ2H) and δ18O (Δδ18O) of tissue-bound organic matter in two tissue types: muscle and dentine collagen. The diet to tissue offset varies by diet type in muscle of all three species, by up to 16 ‰ (Δδ2H) and 2 ‰ (Δδ18O). In dentine collagen, a range of ~20 ‰ in Δδ2H and ~1.5 ‰ in Δδ18O are observed across diets, though in a smaller number of samples. Additionally, we note large variation in Δδ2H and Δδ18O by tissue type (δ2H = ~60 ‰, δ18O = ~3–4 ‰) and more moderate differences by species (up to δ2H = 7.4 ‰, δ18O = 1.5 ‰). The difference in consumer tissue Δδ2H and Δδ18O by diet type is important to consider as a source of isotopic variability for some studies such as migratory research or diet or drinking water reconstructions and (palaeo-)climate inferences drawn from them, particularly in species that may vary their dietary habits.

Here we describe recently recovered crocodyliform remains from the Tamagawa Formation of Kuji Group, Kuji city, northeastern Japan. The material comprises osteoderms, vertebrae, a frontal bone, and isolated teeth. The dorsal paravertebral osteoderms bear a sagittal keel on the posterior half of the element, extending to its caudal margin, which indicates the presence of paralligatorids within the Kuji crocodyliform assemblage. Further, the Kuji crocodyliform assemblage may have consisted of multiple taxa, as the frontal bone lacks the sagittal keel characteristic of paralligatorids. Contemporaneous paralligatorids have been reported from Northeastern China, Mongolia, and Uzbekistan. The discovery of a potential paralligatorid from Kuji, Japan, suggests that paralligatorids were widely distributed across Asia, from coastal to inland regions, during the Late Cretaceous. Furthermore, potential diets of taxa included in the crocodyliform assemblage from Kuji were estimated through dental microwear texture analysis. The dental microwear texture observed in Kuji specimens is distinct from that of piscivorous and small crocodylians (skull length <20 cm), while comparable to that of large crocodylians consuming hard-objects (skull length >20 cm). Considering the existence of a medium-sized species (3 m total length) in the crocodyliform assemblage from Kuji, their diet probably included mid to large sized tetrapods, such as turtles and dinosaurs. (c) 2025 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

Dietary preferences of extant reptiles can be directly observed, whereas diet reconstruction of extinct species typically relies on morphological or dental features. More specific information about the ingested diet is contained in the chemistry of hard tissues. Stable isotopes of calcium and strontium show systematic fractionations between diet and skeletal bioapatite, which is applied for diet and trophic-level reconstructions of extant and extinct vertebrate species. Here, we present the first comprehensive analysis of stable calcium and strontium isotopes of bones and teeth from 28 extant reptiles, including lepidosaurs and archosaurs (crocodilians) with distinct herbivorous to faunivorous feeding behaviour, establishing a dietary reference frame. Both calcium and strontium isotopes exhibit systematic offsets between dietary groups, with insectivores having the highest, herbivores intermediate and carnivores the lowest calcium and strontium isotope values. Although the isotopic trophic-level effect is similar to mammals, the absolute calcium isotope values in reptiles are more positive in each diet category. Combining isotopic data with dental microwear texture analysis enables a refined understanding of reptile feeding ecology and the identification of durophagous diets. This toolbox opens new possibilities for improved dietary reconstructions of extinct taxa, such as dinosaurs and other non-mammalian species in the fossil record.

Dental microwear texture analysis (DMTA) has emerged as a valuable method for investigating the feeding ecology of vertebrates. Over the past decade, three-dimensional topographic data from microscopic regions of tooth surfaces have been collected, and surface texture parameters have been published for both extant and fossil species. However, different types of measurement instruments and surface processing used by respective laboratories conducting DMTA have limited the potential data comparison. In this study, we propose correction formulae for the DMTA data produced by different instruments to facilitate intercomparison. We used six confocal instruments from five laboratories to scan standard tooth samples with strictly defined scan areas. We found significant differences in DMTA parameter values among the different machines, despite scanning the exact same spots. The degree of discrepancy varied considerably, with instruments from the same manufacturer and similar models showing less variation. Some parameters exhibited high correlations between instruments, enabling the development of regression equations for correction formulae. Using these correction formulae, we adjusted published DMTA data and conducted a meta-analysis of extant herbivores to examine the effects of internal and external abrasives. Our findings indicate overall positive effects of internal and external abrasives on DMTA, with varying responses to the abrasives between ruminant and non-ruminant herbivores. The meta-analysis supports the hypothesis that ruminants effectively "wash ingesta" in their rumens, mitigating the impact of external abrasives and reducing overall dental wear.

Dental microwear texture analysis (DMTA) has become a well-established method for dietary inference and reconstruction in both extant and extinct mammals and other tetrapods. As the volume of available data continues to grow, researchers could benefit from combining published data from various studies to perform meta-analyses. However, the different optical profilometers used to capture three-dimensional surface scans for DMTA are known to produce variation even when measuring the same surface. In this study, we compare DMTA data of 36 guinea pigs that received different diets in a controlled feeding experiment, measured using five different instruments: three confocal-scanning microscopes and two confocal laser-scanning microscopes. Each dataset is filtered according to in-house standards of the respective laboratories. Our findings reveal inter-microscope differences in the majority of the 40 DMTA parameters analyzed. Height and volume parameters were the most consistent across instruments, whereas density and complexity parameters exhibited pronounced differences. We thus propose DMTA parameters that were stable regardless of microscope. Despite these inter-microscope variations, the overall results from all instruments consistently show the same dietary differentiation among the guinea pig feeding groups, supporting the suitability of DMTA for reproducible and objective dietary inferences. To enhance data exchange, inter-lab comparability, and collaboration in the future, we propose a roadmap that includes the introduction of device-specific correction equations.

The Amami rabbit (Pentalagus furnessi) and the Ryukyu long-furred rat (Diplothrix legata) are rare, endemic mammals of the Ryukyu Islands. So far, knowledge about their basic ecology is limited. This study aims to expand data on their feeding ecology by dental microwear texture (DMT) analysis using skull specimens (n = 20 for each species) collected as roadkill. DMT data were compared with those from laboratory-reared rodents in controlled feeding experiments, to infer the physical properties of their diets. The results indicated no sexual difference in DMT for either species, suggesting similar diets between males and females. However, a significant seasonal variation was observed in the Ryukyu long-furred rat, with increased DMT roughness in winter, suggesting a dietary shift from more abundant and less mechanically demanding summer foods like soft-bodied invertebrates to harder foods such as acorns. In contrast, the Amami rabbit showed consistently less rough DMT throughout the year. Microwear patterns suggested that the Amami rabbit consumes plants with toughness comparable to bamboo and dry grass. These findings highlight the importance of seasonal dietary shifts in the Ryukyu long-furred rat and the consistent diet of the Amami rabbit, providing insights into their ecological adaptations.

Dental microwear texture analysis (DMTA) is widely applied for inferring diet in vertebrates. Besides diet and ingesta properties, factors like wear stage and bite force may affect microwear formation, potentially leading to tooth position-specific microwear patterns. We investigated DMTA consistency along the upper cheek tooth row in young adult female rats at different growth stages, but with erupted adult dentitions. Bite forces for each molar (M) position were determined using muscle cross-sectional areas and lever arm mechanics. Rats were categorized into three size classes based on increasing skull length. Maximum bite force increased with size, while across all size classes, M3 bite force was almost 1.4 times higher than M1 bite force. In size class 1, M1 and M2 showed higher values than M3 for DMTA complexity, height, and volume parameters, while in size class 3, M1 had the lowest values. Comparing the same tooth position between size classes revealed opposing trends: M1 and M2 showed, for most parameters, decreasing roughness and complexity from size class 1-3, while M3 displayed the opposite trend, with size class 1 showing lowest, and either size class 2 or 3 the highest roughness and complexity values. This suggests that as rats age and M3 fully occludes, it becomes more utilized during mastication. DMTA, being a short-term diet proxy, is influenced by eruption and occlusion status changes. Our findings emphasize the importance of bite force and ontogenetic stage when interpreting microwear patterns and advise to select teeth in full occlusion for diet reconstruction.

Dental microwear texture analysis (DMTA) has been widely used in the study of dietary habits and trends of animals, based on the abrasion patterns preserved in dental enamel. Therefore, it is seen as an important tool when it comes to understanding the ecology, niche partitioning, and competition between co-occurring taxa, both extant and extinct. During the Late Jurassic, sauropod dinosaur faunas were quite diverse, with distinct groups inhabiting the same ecosystems. Being the largest mega-herbivores of their ecosystems, competition for resources could have been a determining factor that led to such diversity, making sauropods a good study-group for DMTA. Here we describe the complete process of creating a large DMTA dataset, from the required pre-analytical molding, casting, and three-dimensional data acquisition to the post-processing steps to quality check the acquired data. A total of 119 teeth attributed to the major sauropod groups from the Late Jurassic were measured for the most commonly analyzed DMTA parameters. We describe in detail the production of dental molds, casts, and the steps taken throughout the measuring process. We also describe the way in which we tested the quality of our data, as well as the taphonomical implications for future studies using the resulting dataset. The end result is the first large DMTA sauropod teeth dataset, consisting of 1011 measurements.

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.

The stable isotope composition of zinc (delta 66Zn), which is an essential trace metal for many biological processes in vertebrates, is increasingly used in ecological, archeological, and paleontological studies to assess diet and trophic level discrimination among vertebrates. However, the limited understanding of dietary controls and isotopic fractionation processes on Zn isotope variability in animal tissues and biofluids limits precise dietary reconstructions. The current study systematically investigates the dietary effects on Zn isotope composition in consumers using a combined controlled feeding experiment and box-modeling approach. For this purpose, 21 rats were fed one of seven distinct animal- and plant-based diets and a total of 148 samples including soft and hard tissue, biofluid, and excreta samples of these individuals were measured for delta 66Zn. Relatively constant Zn isotope fractionation is observed across the different dietary groups for each tissue type, implying that diet is the main factor controlling consumer tissue delta 66Zn values, independent of diet composition. Furthermore, a systematic delta 66Zn diet-enamel fractionation is reported for the first time, enabling diet reconstruction based on delta 66Zn values from tooth enamel. In addition, we investigated the dynamics of Zn isotope variability in the body using a box-modeling approach, providing a model of Zn isotope homeostasis and inferring residence times, while also further supporting the hypothesis that delta 66Zn values of vertebrate tissues are primarily determined by that of the diet. Altogether this provides a solid foundation for refined (paleo)dietary reconstruction using Zn isotopes of vertebrate tissues. Graphical Abstract The delta 66Zn values of vertebrate tissues are primarily determined by the diet and the cycling of zinc.

Dinosaurs 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.

Hard tissue formation patterns and rates reveal details of animal physiology, life history, and environment, but are understudied in reptiles. Here, we use fluorescence labels delivered in vivo and laser confocal scanning microscopy to study tooth and bone formation in a managed group of green iguanas (Iguana iguana, Linné 1758) kept for 1.5 years under experimentally controlled conditions and undergoing several dietary switches. We constrain rates of tooth elongation, which we observe to be slow when enamel is initially deposited (c. 9 µm/day), but then increases exponentially in the dentin root, reaching c. 55 µm/day or more after crown completion. We further constrain the total timing of tooth formation to ∼40-60 days, and observe highly variable timings of tooth resorption onset and replacement. Fluorescent labels clearly indicate cohorts of teeth recruited within Zahnreihen replacement waves, with faster sequential tooth recruitment and greater wave sizes posteriorly, where each wave initiates. Fluorescence further reveals enamel maturation after initial deposition. Rates of hard tissue formation in long bones range from 0.4 to 3.4 µm/day, correlating with animal weight gain and cortical bone recording the entire history of the experiment. We suggest additional labeling experiments to study hard tissue formation patterns in other reptiles, and propose strategies for chemical analyses of hard tissues in order to extract temporal information about past environments, behaviors, and diets from reptilian fossils throughout the Phanerozoic.

The drivers of dental wear and compensatory hypselodont tooth growth are of current research interest. Expanding previous macroscopic dental wear measurements based on microtomographic scans of guinea pigs (Cavia porcellus) fed natural diets, we added diet groups with different predicted drivers of dental wear and analysed how measured variables relate to each other. The teeth of guinea pigs fed either pelleted diets containing external abrasives of various shapes, sizes and percentages (n = 66) or natural whole-leaf diets (n = 36, low-phytolith lucerne or grass or high-phytolith bamboo) were evaluated. The bamboo-fed animals showed the lowest tooth height with deep dentine basins, similar to the pellet-fed animals. Deeper dentine basins generally correlated with higher occlusal surfaces, allowing the hypothesis that changes in the pressure signal due to lower basins could initiate compensatory growth and broadening of the whole tooth surface in hypselodont teeth. Macroscopic dental wear did not categorically differ between whole-leaf or pelleted diets or between diets with internal phytoliths or with external silicate abrasives. Supporting interpretations that tooth wear should be viewed as a response to the biomechanical properties of ingested feed which may or may not be aptly summarized by broad descriptors such as 'whole/pelleted' or 'natural/artificial'.

In mammals, complex dental microwear textures (DMT) representing differently sized and shaped enamel lesions overlaying each other have traditionally been associated with the seeds and kernels in frugivorous diets, as well as with sclerotized insect cuticles. Recently, this notion has been challenged by field observations as well as in vitro experimental data. It remains unclear to what extent each food item contributes to the complexity level and is reflected by the surface texture of the respective tooth position along the molar tooth row. To clarify the potential of seeds and other abrasive dietary items to cause complex microwear textures, we conducted a controlled feeding experiment with rats. Six individual rats each received either a vegetable mix, a fruit mix, a seed mix, whole crickets, whole black soldier fly larvae, or whole day-old-chicks. These diets were subjected to material testing to obtain mechanical properties, such as Young’s modulus, yield strength, and food hardness (as indicated by texture profile analysis [TPA] tests). Seeds and crickets caused the highest surface complexity. The fruit mix, seed mix, and crickets caused the deepest wear features. Moreover, several diets resulted in an increasing wear gradient from the first to the second molar, suggesting that increasing bite force along the tooth row affects dental wear in rats on these diets. Mechanical properties of the diets showed different correlations with DMT obtained for the first and second molars. The first molar wear was mostly correlated with maximum TPA hardness, while the second molar wear was strongly correlated with maximum yield stress, mean TPA hardness, and maximum TPA hardness. This indicates a complex relationship between chewing mechanics, food mechanical properties, and observed DMT. Our results show that, in rats, seeds are the main cause of complex microwear textures but that hard insect body parts can also cause high complexity. However, the similarity in parameter values of surface textures resulting from seed and cricket consumption did not allow differentiation between these two diets in our experimental approach.

This record contains the results of the 3D surface texture analysis on surfaces from three datasets: Sheep's teeth Guinea pig's teeth Lithic flakes Each surface has been processed in batch with a template. The result of the analysis on each surface is saved in MNT format (including all original and processed surfaces, as well as results) and exported to a PDF file. Ultimately, the results are collated into CSV files (see https://doi.org/10.5281/). The analysis has been performed with ConfoMap (a derivative of MountainsMap Imaging Topography) v. 8.0.9173.

RATIONALE Blood water oxygen isotope compositions can provide valuable insights into physiological processes and ecological patterns. While blood samples are commonly drawn for medical or scientific purposes, blood fractions are infrequently measured for oxygen isotopic compositions (δ18 O) because such measurements are time consuming and expensive. METHODS We sampled blood from sheep, goats, and iguanas raised in field and animal laboratories into serum, EDTA, heparin, and uncoated plastic vials commonly used in medical and scientific research, then separated red blood cell (RBC) and plasma or serum blood fractions. These were injected into helium-flushed Exetainer tubes where they naturally outgassed endogenous CO2 (goat blood), or into He- and CO2 -flushed tubes (iguana blood). The CO2 gas was sampled on a GasBench II system, and δ18 O was measured by an isotope ratio mass spectrometer (IRMS). RESULTS Repeated δ18 O measurements were stable over multiple days. The addition of desiccated blood solids to water standards had little impact on their δ18 O measurements, suggesting that organic molecular constituents within blood serum and plasma do not interfere with blood water δ18 O values. We observed slight but statistically significant δ18 O offsets between plasma, serum and RBC fractions. Mass-dependent body water turnover times for iguanas were derived from the data. CONCLUSIONS We demonstrate that a simple blood-CO2 equilibration method using the GasBench can quickly, reliably and accurately characterize water δ18 O in the plasma, RBC, and whole blood fractions of mammalian and reptilian blood samples (precision ≤ 0.1 ‰). This method will expand the application of blood stable isotope analysis in physiological and medical research.

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.