The Armenian highlands encompasses rugged and environmentally diverse landscapes and is character... more The Armenian highlands encompasses rugged and environmentally diverse landscapes and is characterized by a mosaic of distinct ecological niches and large temperature gradients. Strong seasonal fluctuations in resource availability along topographic gradients likely prompted Pleistocene hominin groups to adapt by adjusting their mobility strategies. However, the role that elevated landscapes played in hunter-gatherer settlement systems during the Late Pleistocene (Middle Palaeolithic [MP]) remains poorly understood. At 1640 m above sea level, the MP site of Kalavan 2 (Armenia) is ideally positioned for testing hypotheses involving elevation-dependent seasonal mobility and subsistence strategies. Renewed excavations at Kalavan 2 exposed three main occupation horizons and ten additional low densities lithic and faunal assemblages. The results provide a new chronological, stratigraphical, and paleoenvironmental framework for hominin behaviors between ca. 60 to 45 ka. The evidence presen...
Pre-print of the manuscript "Dental microwear texture analysis in Toothfrax and MountainsMap... more Pre-print of the manuscript "Dental microwear texture analysis in Toothfrax and MountainsMap® SSFA module: Different software packages, different results?" Submitted to PCI Paleontology. See related identifiers for the associated supplementary materials.
Research Compendium for the paper on SSFA comparison. See pre-print with the DOI 10.5281/zenodo.4... more Research Compendium for the paper on SSFA comparison. See pre-print with the DOI 10.5281/zenodo.4671438. Data from ConfoMap v. 8.2.9468. The Docker image of the Python analysis has a separate DOI 10.5281/zenodo.4302091.
Docker image of the Python analysis. See "Python_analysis/RUN_DOCKER.md in the record for de... more Docker image of the Python analysis. See "Python_analysis/RUN_DOCKER.md in the record for details.
This is the first release of this repository. The README.md document details the steps to downloa... more This is the first release of this repository. The README.md document details the steps to download all the files from a given Zenodo record, either using R or Python.
Understanding artifact variability, and especially the role of different raw materials and their ... more Understanding artifact variability, and especially the role of different raw materials and their possibleuse by past humans, is one of the most debated topics in Pleistocene archaeo logy. Functional studiesare critical to determine artifact use, and thus to address fundamental questions about the evolutionof human behaviour.The new Laboratory for Traceology and Controlled Experiments (TraCEr) is basedat the MONREPOS Archaeological Research Centre and Museum for HumanBehavioural Evolution. Its goal is to carry out ground-breaking func tio nalstudies that combine 1) methodological development and2) fundamental research on Pleistocene and Early Holocene archaeology.
ConfoMap templates for each surface in MNT format (including all original and processed surfaces,... more ConfoMap templates for each surface in MNT format (including all original and processed surfaces, as well as results). Each template has also been exported to a PDF file. Additionally, results are collated into 'brushing_v2.csv'
In mammals, tooth function, and its efficiency, depends both on the mechanical properties of the ... more In mammals, tooth function, and its efficiency, depends both on the mechanical properties of the food and on chewing dynamics. These aspects have rarely been studied in combination and/or at the intraspecific level. Here we applied 3D dental surface texture analysis to a sample of field voles (Microtus agrestis) trapped from Finnish Lapland at different seasons and localities to test for inter-population variations. We also explored intra-individual variation in chewing dynamics by analysing two facets on the second upper molars. Our results confirm that the two localities have similar environments and that the voles feed on the same items there. On the other hand, the texture data suggest that diets are seasonally variable, probably due to varying concentrations of abrasives. Lastly, the textures on the buccal facets are more isotropic and their direction deviates more from the mesial chewing direction than the lingual facets. We interpret these results as reflecting food, rather than chewing, movements, where food particles are more guided on the lingual side of the molars. This has implications for the application of dental microwear analysis to fossils: only homologous facets can be compared, even when the molar row seems to constitute a functional unit.
Mammal teeth have evolved morphologies that allow for the efficient mechanical processing of diff... more Mammal teeth have evolved morphologies that allow for the efficient mechanical processing of different foods, therefore increasing dietary energy uptake for maintenance of high metabolic demands. However, individuals masticate foods with biomechanical properties at odds with the optimal function of a given tooth morphology. Here, we investigate tooth form and function using two quantitative 3D methods at different scales on the same individuals of nine bovid species. Dental topometry quantifies the gross morphology, and therefore, reflects evolutionary adaptive patterns. Surface texture analysis infers mechanical occlusal events, which reflect the actual tooth function, and is free from the influence of morphology. We found that tough foods can be satisfactorily exploited by grazing species with enamel ridge morphologies not more complex than those found in intermediate feeders and browsers. Thus, the evolution of enamel complexity is likely determined by a balance between adaptation and constraints. Wider enamel ridges seem to be a common functional trait in bovids to compensate for severe wear from abrasive foods and/or chipping from hard foods. Our results demonstrate that supposedly essential functional adaptations in tooth morphology may not be required to process food efficiently. This emphasizes the large plasticity between “optimal” morphology and the potential function of the tooth, and underscores the need to appreciate (apparently) maladaptive structures in mammalian evolution as nevertheless effective functioning units.
Plant-herbivore interactions are hypothesized to drive vole population cycles through the grazing... more Plant-herbivore interactions are hypothesized to drive vole population cycles through the grazing-induced production of phytoliths in leaves. Phytoliths act as mechanical defences because they deter herbivory and lower growth rates in mammals. However, how phytoliths impair herbivore performance is still unknown. Here, we tested whether the amount of phytoliths changes tooth wear patterns. If confirmed, abrasion from phytoliths could play a role in population crashes. We applied dental microwear texture analysis (DMTA) to laboratory and wild voles. Lab voles were fed two pelleted diets with differing amounts of silicon, which produced similar dental textures. This was most probably due to the loss of food mechanical properties through pelletization and/or the small difference in silicon concentration between diets. Wild voles were trapped in Poland during spring and summer, and every year across a population cycle. In spring, voles feed on silica-rich monocotyledons, while in the su...
Neoecology and paleoecology both seek to answer the same questions, albeit using different materi... more Neoecology and paleoecology both seek to answer the same questions, albeit using different material, at different time scales and with different limitations. Nevertheless, too often, neoecologists neglect paleoecology, and paleoecologists only use neoecology as a baseline for actualism. One reason for this is the lack of tools that can be applied to both fields. This is a review of the contributions to both neoecology and paleoecology of three-dimensional (3D) dental microwear texture analysis (DMTA), a method that can act as a bridge between these fields. DMTA studies can be grouped according to the type of ecological questions researchers seek to answer: specific ecology, intra-specific ecology, niche partitioning and dietary overlap, and ecology over time. The first question has been the main focus of research; the other three were only superficially studied. In this review, selected examples will be presented to demonstrate that DMTA, as one of the few tools that can be applied to both modern and fossil samples, has been used to address key ecological questions in mammalian neoecology and paleoecology. With the wide range of neoecological and paleoecological questions that DMTA can answer, it is clear that this methodology will be used increasingly in the future, possibly in combination with other ecological proxies.
In the Arctic, food limitation is one of the driving factors behind small mammal population fluct... more In the Arctic, food limitation is one of the driving factors behind small mammal population fluctuations. Active throughout the year, voles and lemmings (arvicoline rodents) are central prey in arctic food webs. Snow cover, however, makes the estimation of their winter diet challenging. We analyzed the isotopic composition of ever-growing incisors from species of voles and lemmings in northern Finland trapped in the spring and autumn. We found that resources appear to be reasonably partitioned and largely congruent with phylogeny. Our results reveal that winter resource use can be inferred from the tooth isotopic composition of rodents sampled in the spring, when trapping can be conducted, and that resources appear to be partitioned via competition under the snow.
Large herbivorous mammals have evolved chewing systems capable of processing a large variety of s... more Large herbivorous mammals have evolved chewing systems capable of processing a large variety of structurally diverse foods. Three-dimensional (3D) surface texture parameters are applied to investigate wear mechanisms related to tooth morphology, food source, and chewing dynamics. We tested 46 industrial 3D surface texture parameters for their capability to robustly indicate specific biomechanics in two grazing (Blue Wildebeest and Grevy's Zebra) and two browsing (Giraffe and Black Rhinoceros) ungulate mammals. These species inhabit sub-Saharan Africa and represent foregut and hindgut fermenters. The results did not indicate a wavelength threshold that can consistently separate the structural (morphology) from the functional (diet) signals in the microtextures of the species studied. This implies that no structural signal is present at this scale. The most effective surface texture parameters for discriminating species with different diets are the parameters of height (Sa), functional (Smc, Sxp), volume (Vmc, Vv, Vvc, Vvv), density of furrows (medf), isotropy (IsT), and flatness (FLTt, FLTp, FLTq) of tooth surface textures. The surface textures of grazers are characterised by more anisotropy, higher height and volume values, more peaks and deeper furrows than browsers. In addition to discriminate between dietary preferences, surface texture parameters reflect the dynamic processes in the occlusal space that can scarcely be observed in situ. We found that during mastication, the occlusal gap is larger when the food consumed consists of more grasses and is smaller when browse is comminuted. With the narrowing of the occlusal gap, high peaks of surface texture are more likely to be ground down, either by attrition (tooth-tooth contact) or by fast fluid movements due to hydrodynamic pressures. A larger food bolus, in turn, is more likely to prevent peaks from being flattened. Thus, the surface texture parameters provide a tool set for understanding masticatory function directly at the enamel surface at a micrometre scale.
Mammals inhabit all types of environments and have evolved chewing systems capable of processing ... more Mammals inhabit all types of environments and have evolved chewing systems capable of processing a huge variety of structurally diverse food components. Surface textures of cheek teeth should thus reflect the mechanisms of wear as well as the functional traits involved. We employed surface textures parameters from ISO/DIS 25178 and scale-sensitive fractal analysis (SSFA) to quantify dental wear in herbivorous mammals at the level of an individual wear enamel facet. We evaluated cheek dentitions of two grazing ungulates: the Blue Wildebeest (Connochaetes taurinus) and the Grevy's Zebra (Equus grevyi). Both inhabit the east African grassland savanna habitat, but they belong to fundamentally different taxonomic units. We tested the hypothesis that the foregut fermenting wildebeest and the hindgut fermenting zebra show functional traits in their dentitions that relate to their specific mode of food-composition processing and digestion. In general, surface texture parameters from SSFA as well as ISO/DIS 25178 indicated that individual enamel ridges acting as crushing blades and individual wear facets of upper cheek teeth are significantly different in surface textures in the zebra when compared with the wildebeest. We interpreted the complexity and anisotropy signals to be clearly related to the brittle, dry grass component in the diet of the zebra, unlike the wildebeest, which ingests a more heterogeneous diet including fresh grass and herbs. Thus, SSFA and ISO parameters allow distinctions within the subtle dietary strategies that evolved in herbivorous ungulates with fundamentally different systematic affinities but which exploit a similar dietary niche.
The objective of this study is to estimate changes in feeding preferences of the proboscidean spe... more The objective of this study is to estimate changes in feeding preferences of the proboscidean species Gomphotherium subtapiroideum (Schlesinger 1917) by means of dental microwear analyses. The dietary changes are first evaluated through the ontogeny of this species, between juveniles and adults, and are then studied through geological time, from early Middle Miocene (MN5) to middle Late Miocene (MN8-9) localities of the German Molasse Basin. The microwear patterns of juvenile and adult individuals of G. subtapiroideum from Sandelzhausen (MN5) differ merely by the variable ''length of scratches'', emphasizing longer jaw movements during mastication in adults. The microwear signatures of G. subtapiroideum do not vary significantly between the two geological time periods studied, but reflect mixed feeding preferences in both cases. These results imply that, despite an important environmental change at that time (drying and opening), the ecology of G. subtapiroideum and, especially, its feeding habits were not affected. Its dental microwear pattern is then compared with those of other species of Proboscidea from the Middle-Late Miocene of Germany, namely Deinotherium giganteum and Gomphotherium steinheimense. Keywords Diet Á Environment Á Europe Á Miocene Á Proboscidea Á Weaning Kurzfassung Die vorliegende Untersuchung hat das Ziel anhand von ,,Microwear''-Analysen an Backenzähnen eventuelle Veränderungen von Futterpräferenzen der Rüsseltierart Gomphotherium subtapiroideum (Schlesinger 1917) abzuklären. Hierbei werden eventuelle innerartliche Veränderungen zum einen im Laufe der Ontogenie, also zwischen juvenilen und adulten Tieren, zum anderen im Laufe der Zeit vom frühen Mittel-Miozän (MN5) zum mittleren Ober-Miozän (MN8-9), basierend auf Material von Fundstellen aus dem deutschen Molassebecken, ausgewertet. Das ,,Microwear''-Muster von G. subtapiroideum aus Sandelzhausen (MN5) zeigt keine nennenswerten Unterschiede zwischen juvenilen und adulten Individuen, außer für die Länge der Kratzer, die wohl von längeren Kieferbewegungen bei adulten Tieren herrühren. Die ,,Mircowear''-Signatur von G. subtapiroideum lässt auch keine wesentliche Veränderung zwischen den beiden, untersuchten geologischen Zeiten erkennen; in beiden Fällen ist das Signal typisch für ,,mixed-feeder''. Dieses Ergebnis spricht dafür, dass, obwohl in diesem Zeitraum eine nicht unwesentliche Veränderung zu einer allgemein trockeneren und offeneren Umwelt statt gefunden hat, dies keinen Einfluß auf die Lebensweise und das
Although low in diversity, megaherbivores (mammals weighting over 10 3 kg) and especially probosc... more Although low in diversity, megaherbivores (mammals weighting over 10 3 kg) and especially proboscideans have a powerful impact on the structure and dynamics of present-day ecosystems. During the Neogene (23 to 2.6 Ma) of Europe, the diversity and geographic distribution of these megaherbivores was much greater. Nonetheless, their role in past ecosystems is unclear. Nutrition is one of the main bonds between organisms and their environment. Therefore, the ecology of organisms can be inferred from their dietary habits. The present study is aimed at characterizing the feeding habits of diverse megaherbivores through dental microwear analyses. This method was applied on cheek teeth of three sympatric species of proboscideans from the middle/late Miocene of the Molasse Basin in Southern Germany: Gomphotherium subtapiroideum, Gomphotherium steinheimense, and Deinotherium giganteum. The microwear signatures are significantly different between these taxa, suggesting differences in feeding habits and ecological niches within a woodland environment. D. giganteum probably browsed on dicotyledonous foliages whereas the two species of gomphotheres were neither strict grazers nor strict browsers and instead probably fed on a large spectrum of vegetal resources. The differences of occlusal molar morphology between the two gomphotheres are supported by the dental microwear pattern. Indeed, G. subtapiroideum probably ingested more abrasive material than G. steinheimense. Thus, our results suggest that these proboscideans did not compete for food resources.
Newly colonised, isolated habitats, like islands, provide diverse niches to be filled and are pro... more Newly colonised, isolated habitats, like islands, provide diverse niches to be filled and are prone to facilitate ecological separation which might lead to an adaptive radiation. Examples of such radiations can be found in the Mediterranean for the genera Candiacervus (Crete), Nesogoral (Sardinia) and Hoplitomeryx (Gargano). A different strategy to cope with limited resources on islands is generalism. We test whether populations of the endemic bovid Myotragus balearicus from two sites and Pleistocene as well as Holocene levels on Mallorca island displays ecological separation indicated by diet, or whether the species shifted its dietary trait towards generalism. We expect to find either: (1) dietary divergence in space and time (between sites and stratigraphic levels), which would indicate niche partitioning and/or a shift in dietary traits due to environmental influences; or (2) dietary congruence in a less specialised, generalistic dietary strategy in space and time which would indicate a flexible trait to cope with instable resource availability. We compare individuals from a fossil assemblage at a northern site and one assemblage from the eastern coast in terms of their dietary traits. Traits are reconstructed using dental dietary proxies, complementary in time scale and resolution. (1) 3D-dental topometry and (2) enamel surface texture analysis. Data suggest that individuals from both assemblages of M. balearicus behaved as variable browse dominated intermediate feeders. We thus conclude that the observed variability relates to a shift towards generalism as a subsistence strategy. We consider hypsodonty the pre-adaptation for this life style that enabled M. balearicus to exploit almost any food source in its energetically restricted island habitat.
The Armenian highlands encompasses rugged and environmentally diverse landscapes and is character... more The Armenian highlands encompasses rugged and environmentally diverse landscapes and is characterized by a mosaic of distinct ecological niches and large temperature gradients. Strong seasonal fluctuations in resource availability along topographic gradients likely prompted Pleistocene hominin groups to adapt by adjusting their mobility strategies. However, the role that elevated landscapes played in hunter-gatherer settlement systems during the Late Pleistocene (Middle Palaeolithic [MP]) remains poorly understood. At 1640 m above sea level, the MP site of Kalavan 2 (Armenia) is ideally positioned for testing hypotheses involving elevation-dependent seasonal mobility and subsistence strategies. Renewed excavations at Kalavan 2 exposed three main occupation horizons and ten additional low densities lithic and faunal assemblages. The results provide a new chronological, stratigraphical, and paleoenvironmental framework for hominin behaviors between ca. 60 to 45 ka. The evidence presen...
Pre-print of the manuscript "Dental microwear texture analysis in Toothfrax and MountainsMap... more Pre-print of the manuscript "Dental microwear texture analysis in Toothfrax and MountainsMap® SSFA module: Different software packages, different results?" Submitted to PCI Paleontology. See related identifiers for the associated supplementary materials.
Research Compendium for the paper on SSFA comparison. See pre-print with the DOI 10.5281/zenodo.4... more Research Compendium for the paper on SSFA comparison. See pre-print with the DOI 10.5281/zenodo.4671438. Data from ConfoMap v. 8.2.9468. The Docker image of the Python analysis has a separate DOI 10.5281/zenodo.4302091.
Docker image of the Python analysis. See "Python_analysis/RUN_DOCKER.md in the record for de... more Docker image of the Python analysis. See "Python_analysis/RUN_DOCKER.md in the record for details.
This is the first release of this repository. The README.md document details the steps to downloa... more This is the first release of this repository. The README.md document details the steps to download all the files from a given Zenodo record, either using R or Python.
Understanding artifact variability, and especially the role of different raw materials and their ... more Understanding artifact variability, and especially the role of different raw materials and their possibleuse by past humans, is one of the most debated topics in Pleistocene archaeo logy. Functional studiesare critical to determine artifact use, and thus to address fundamental questions about the evolutionof human behaviour.The new Laboratory for Traceology and Controlled Experiments (TraCEr) is basedat the MONREPOS Archaeological Research Centre and Museum for HumanBehavioural Evolution. Its goal is to carry out ground-breaking func tio nalstudies that combine 1) methodological development and2) fundamental research on Pleistocene and Early Holocene archaeology.
ConfoMap templates for each surface in MNT format (including all original and processed surfaces,... more ConfoMap templates for each surface in MNT format (including all original and processed surfaces, as well as results). Each template has also been exported to a PDF file. Additionally, results are collated into 'brushing_v2.csv'
In mammals, tooth function, and its efficiency, depends both on the mechanical properties of the ... more In mammals, tooth function, and its efficiency, depends both on the mechanical properties of the food and on chewing dynamics. These aspects have rarely been studied in combination and/or at the intraspecific level. Here we applied 3D dental surface texture analysis to a sample of field voles (Microtus agrestis) trapped from Finnish Lapland at different seasons and localities to test for inter-population variations. We also explored intra-individual variation in chewing dynamics by analysing two facets on the second upper molars. Our results confirm that the two localities have similar environments and that the voles feed on the same items there. On the other hand, the texture data suggest that diets are seasonally variable, probably due to varying concentrations of abrasives. Lastly, the textures on the buccal facets are more isotropic and their direction deviates more from the mesial chewing direction than the lingual facets. We interpret these results as reflecting food, rather than chewing, movements, where food particles are more guided on the lingual side of the molars. This has implications for the application of dental microwear analysis to fossils: only homologous facets can be compared, even when the molar row seems to constitute a functional unit.
Mammal teeth have evolved morphologies that allow for the efficient mechanical processing of diff... more Mammal teeth have evolved morphologies that allow for the efficient mechanical processing of different foods, therefore increasing dietary energy uptake for maintenance of high metabolic demands. However, individuals masticate foods with biomechanical properties at odds with the optimal function of a given tooth morphology. Here, we investigate tooth form and function using two quantitative 3D methods at different scales on the same individuals of nine bovid species. Dental topometry quantifies the gross morphology, and therefore, reflects evolutionary adaptive patterns. Surface texture analysis infers mechanical occlusal events, which reflect the actual tooth function, and is free from the influence of morphology. We found that tough foods can be satisfactorily exploited by grazing species with enamel ridge morphologies not more complex than those found in intermediate feeders and browsers. Thus, the evolution of enamel complexity is likely determined by a balance between adaptation and constraints. Wider enamel ridges seem to be a common functional trait in bovids to compensate for severe wear from abrasive foods and/or chipping from hard foods. Our results demonstrate that supposedly essential functional adaptations in tooth morphology may not be required to process food efficiently. This emphasizes the large plasticity between “optimal” morphology and the potential function of the tooth, and underscores the need to appreciate (apparently) maladaptive structures in mammalian evolution as nevertheless effective functioning units.
Plant-herbivore interactions are hypothesized to drive vole population cycles through the grazing... more Plant-herbivore interactions are hypothesized to drive vole population cycles through the grazing-induced production of phytoliths in leaves. Phytoliths act as mechanical defences because they deter herbivory and lower growth rates in mammals. However, how phytoliths impair herbivore performance is still unknown. Here, we tested whether the amount of phytoliths changes tooth wear patterns. If confirmed, abrasion from phytoliths could play a role in population crashes. We applied dental microwear texture analysis (DMTA) to laboratory and wild voles. Lab voles were fed two pelleted diets with differing amounts of silicon, which produced similar dental textures. This was most probably due to the loss of food mechanical properties through pelletization and/or the small difference in silicon concentration between diets. Wild voles were trapped in Poland during spring and summer, and every year across a population cycle. In spring, voles feed on silica-rich monocotyledons, while in the su...
Neoecology and paleoecology both seek to answer the same questions, albeit using different materi... more Neoecology and paleoecology both seek to answer the same questions, albeit using different material, at different time scales and with different limitations. Nevertheless, too often, neoecologists neglect paleoecology, and paleoecologists only use neoecology as a baseline for actualism. One reason for this is the lack of tools that can be applied to both fields. This is a review of the contributions to both neoecology and paleoecology of three-dimensional (3D) dental microwear texture analysis (DMTA), a method that can act as a bridge between these fields. DMTA studies can be grouped according to the type of ecological questions researchers seek to answer: specific ecology, intra-specific ecology, niche partitioning and dietary overlap, and ecology over time. The first question has been the main focus of research; the other three were only superficially studied. In this review, selected examples will be presented to demonstrate that DMTA, as one of the few tools that can be applied to both modern and fossil samples, has been used to address key ecological questions in mammalian neoecology and paleoecology. With the wide range of neoecological and paleoecological questions that DMTA can answer, it is clear that this methodology will be used increasingly in the future, possibly in combination with other ecological proxies.
In the Arctic, food limitation is one of the driving factors behind small mammal population fluct... more In the Arctic, food limitation is one of the driving factors behind small mammal population fluctuations. Active throughout the year, voles and lemmings (arvicoline rodents) are central prey in arctic food webs. Snow cover, however, makes the estimation of their winter diet challenging. We analyzed the isotopic composition of ever-growing incisors from species of voles and lemmings in northern Finland trapped in the spring and autumn. We found that resources appear to be reasonably partitioned and largely congruent with phylogeny. Our results reveal that winter resource use can be inferred from the tooth isotopic composition of rodents sampled in the spring, when trapping can be conducted, and that resources appear to be partitioned via competition under the snow.
Large herbivorous mammals have evolved chewing systems capable of processing a large variety of s... more Large herbivorous mammals have evolved chewing systems capable of processing a large variety of structurally diverse foods. Three-dimensional (3D) surface texture parameters are applied to investigate wear mechanisms related to tooth morphology, food source, and chewing dynamics. We tested 46 industrial 3D surface texture parameters for their capability to robustly indicate specific biomechanics in two grazing (Blue Wildebeest and Grevy's Zebra) and two browsing (Giraffe and Black Rhinoceros) ungulate mammals. These species inhabit sub-Saharan Africa and represent foregut and hindgut fermenters. The results did not indicate a wavelength threshold that can consistently separate the structural (morphology) from the functional (diet) signals in the microtextures of the species studied. This implies that no structural signal is present at this scale. The most effective surface texture parameters for discriminating species with different diets are the parameters of height (Sa), functional (Smc, Sxp), volume (Vmc, Vv, Vvc, Vvv), density of furrows (medf), isotropy (IsT), and flatness (FLTt, FLTp, FLTq) of tooth surface textures. The surface textures of grazers are characterised by more anisotropy, higher height and volume values, more peaks and deeper furrows than browsers. In addition to discriminate between dietary preferences, surface texture parameters reflect the dynamic processes in the occlusal space that can scarcely be observed in situ. We found that during mastication, the occlusal gap is larger when the food consumed consists of more grasses and is smaller when browse is comminuted. With the narrowing of the occlusal gap, high peaks of surface texture are more likely to be ground down, either by attrition (tooth-tooth contact) or by fast fluid movements due to hydrodynamic pressures. A larger food bolus, in turn, is more likely to prevent peaks from being flattened. Thus, the surface texture parameters provide a tool set for understanding masticatory function directly at the enamel surface at a micrometre scale.
Mammals inhabit all types of environments and have evolved chewing systems capable of processing ... more Mammals inhabit all types of environments and have evolved chewing systems capable of processing a huge variety of structurally diverse food components. Surface textures of cheek teeth should thus reflect the mechanisms of wear as well as the functional traits involved. We employed surface textures parameters from ISO/DIS 25178 and scale-sensitive fractal analysis (SSFA) to quantify dental wear in herbivorous mammals at the level of an individual wear enamel facet. We evaluated cheek dentitions of two grazing ungulates: the Blue Wildebeest (Connochaetes taurinus) and the Grevy's Zebra (Equus grevyi). Both inhabit the east African grassland savanna habitat, but they belong to fundamentally different taxonomic units. We tested the hypothesis that the foregut fermenting wildebeest and the hindgut fermenting zebra show functional traits in their dentitions that relate to their specific mode of food-composition processing and digestion. In general, surface texture parameters from SSFA as well as ISO/DIS 25178 indicated that individual enamel ridges acting as crushing blades and individual wear facets of upper cheek teeth are significantly different in surface textures in the zebra when compared with the wildebeest. We interpreted the complexity and anisotropy signals to be clearly related to the brittle, dry grass component in the diet of the zebra, unlike the wildebeest, which ingests a more heterogeneous diet including fresh grass and herbs. Thus, SSFA and ISO parameters allow distinctions within the subtle dietary strategies that evolved in herbivorous ungulates with fundamentally different systematic affinities but which exploit a similar dietary niche.
The objective of this study is to estimate changes in feeding preferences of the proboscidean spe... more The objective of this study is to estimate changes in feeding preferences of the proboscidean species Gomphotherium subtapiroideum (Schlesinger 1917) by means of dental microwear analyses. The dietary changes are first evaluated through the ontogeny of this species, between juveniles and adults, and are then studied through geological time, from early Middle Miocene (MN5) to middle Late Miocene (MN8-9) localities of the German Molasse Basin. The microwear patterns of juvenile and adult individuals of G. subtapiroideum from Sandelzhausen (MN5) differ merely by the variable ''length of scratches'', emphasizing longer jaw movements during mastication in adults. The microwear signatures of G. subtapiroideum do not vary significantly between the two geological time periods studied, but reflect mixed feeding preferences in both cases. These results imply that, despite an important environmental change at that time (drying and opening), the ecology of G. subtapiroideum and, especially, its feeding habits were not affected. Its dental microwear pattern is then compared with those of other species of Proboscidea from the Middle-Late Miocene of Germany, namely Deinotherium giganteum and Gomphotherium steinheimense. Keywords Diet Á Environment Á Europe Á Miocene Á Proboscidea Á Weaning Kurzfassung Die vorliegende Untersuchung hat das Ziel anhand von ,,Microwear''-Analysen an Backenzähnen eventuelle Veränderungen von Futterpräferenzen der Rüsseltierart Gomphotherium subtapiroideum (Schlesinger 1917) abzuklären. Hierbei werden eventuelle innerartliche Veränderungen zum einen im Laufe der Ontogenie, also zwischen juvenilen und adulten Tieren, zum anderen im Laufe der Zeit vom frühen Mittel-Miozän (MN5) zum mittleren Ober-Miozän (MN8-9), basierend auf Material von Fundstellen aus dem deutschen Molassebecken, ausgewertet. Das ,,Microwear''-Muster von G. subtapiroideum aus Sandelzhausen (MN5) zeigt keine nennenswerten Unterschiede zwischen juvenilen und adulten Individuen, außer für die Länge der Kratzer, die wohl von längeren Kieferbewegungen bei adulten Tieren herrühren. Die ,,Mircowear''-Signatur von G. subtapiroideum lässt auch keine wesentliche Veränderung zwischen den beiden, untersuchten geologischen Zeiten erkennen; in beiden Fällen ist das Signal typisch für ,,mixed-feeder''. Dieses Ergebnis spricht dafür, dass, obwohl in diesem Zeitraum eine nicht unwesentliche Veränderung zu einer allgemein trockeneren und offeneren Umwelt statt gefunden hat, dies keinen Einfluß auf die Lebensweise und das
Although low in diversity, megaherbivores (mammals weighting over 10 3 kg) and especially probosc... more Although low in diversity, megaherbivores (mammals weighting over 10 3 kg) and especially proboscideans have a powerful impact on the structure and dynamics of present-day ecosystems. During the Neogene (23 to 2.6 Ma) of Europe, the diversity and geographic distribution of these megaherbivores was much greater. Nonetheless, their role in past ecosystems is unclear. Nutrition is one of the main bonds between organisms and their environment. Therefore, the ecology of organisms can be inferred from their dietary habits. The present study is aimed at characterizing the feeding habits of diverse megaherbivores through dental microwear analyses. This method was applied on cheek teeth of three sympatric species of proboscideans from the middle/late Miocene of the Molasse Basin in Southern Germany: Gomphotherium subtapiroideum, Gomphotherium steinheimense, and Deinotherium giganteum. The microwear signatures are significantly different between these taxa, suggesting differences in feeding habits and ecological niches within a woodland environment. D. giganteum probably browsed on dicotyledonous foliages whereas the two species of gomphotheres were neither strict grazers nor strict browsers and instead probably fed on a large spectrum of vegetal resources. The differences of occlusal molar morphology between the two gomphotheres are supported by the dental microwear pattern. Indeed, G. subtapiroideum probably ingested more abrasive material than G. steinheimense. Thus, our results suggest that these proboscideans did not compete for food resources.
Newly colonised, isolated habitats, like islands, provide diverse niches to be filled and are pro... more Newly colonised, isolated habitats, like islands, provide diverse niches to be filled and are prone to facilitate ecological separation which might lead to an adaptive radiation. Examples of such radiations can be found in the Mediterranean for the genera Candiacervus (Crete), Nesogoral (Sardinia) and Hoplitomeryx (Gargano). A different strategy to cope with limited resources on islands is generalism. We test whether populations of the endemic bovid Myotragus balearicus from two sites and Pleistocene as well as Holocene levels on Mallorca island displays ecological separation indicated by diet, or whether the species shifted its dietary trait towards generalism. We expect to find either: (1) dietary divergence in space and time (between sites and stratigraphic levels), which would indicate niche partitioning and/or a shift in dietary traits due to environmental influences; or (2) dietary congruence in a less specialised, generalistic dietary strategy in space and time which would indicate a flexible trait to cope with instable resource availability. We compare individuals from a fossil assemblage at a northern site and one assemblage from the eastern coast in terms of their dietary traits. Traits are reconstructed using dental dietary proxies, complementary in time scale and resolution. (1) 3D-dental topometry and (2) enamel surface texture analysis. Data suggest that individuals from both assemblages of M. balearicus behaved as variable browse dominated intermediate feeders. We thus conclude that the observed variability relates to a shift towards generalism as a subsistence strategy. We consider hypsodonty the pre-adaptation for this life style that enabled M. balearicus to exploit almost any food source in its energetically restricted island habitat.
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Papers by Ivan Calandra