Publications by authors named "Ellen Schulz-Kornas"

21 Publications

  • Page 1 of 1

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

J R Soc Interface 2021 Jul 21;18(180):20210139. Epub 2021 Jul 21.

Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland.

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 (, = 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.
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http://dx.doi.org/10.1098/rsif.2021.0139DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8292012PMC
July 2021

Dental microwear texture gradients in guinea pigs reveal that material properties of the diet affect chewing behaviour.

J Exp Biol 2021 07 12;224(13). Epub 2021 Jul 12.

Applied and Analytical Palaeontology, Institute of Geosciences, Johannes Gutenberg University, J.-J.-Becher-Weg 21, 55128 Mainz, Germany.

Dental microwear texture analysis (DMTA) is widely used for diet inferences in extant and extinct vertebrates. Often, a reference tooth position is analysed in extant specimens, while isolated teeth are lumped together in fossil datasets. It is therefore important to test whether dental microwear texture (DMT) is tooth position specific and, if so, what causes the differences in wear. Here, we present results from controlled feeding experiments with 72 guinea pigs, which received either fresh or dried natural plant diets of different phytolith content (lucerne, grass, bamboo) or pelleted diets with and without mineral abrasives (frequently encountered by herbivorous mammals in natural habitats). We tested for gradients in dental microwear texture along the upper cheek tooth row. Regardless of abrasive content, guinea pigs on pelleted diets displayed an increase in surface roughness along the tooth row, indicating that posterior tooth positions experience more wear compared with anterior teeth. Guinea pigs feedings on plants of low phytolith content and low abrasiveness (fresh and dry lucerne, fresh grass) showed almost no DMT differences between tooth positions, while individuals feeding on more abrasive plants (dry grass, fresh and dry bamboo) showed a gradient of decreasing surface roughness along the tooth row. We suggest that plant feeding involves continuous intake and comminution by grinding, resulting in posterior tooth positions mainly processing food already partly comminuted and moistened. Pelleted diets require crushing, which exerts higher loads, especially on posterior tooth positions, where bite forces are highest. These differences in chewing behaviour result in opposing wear gradients for plant versus pelleted diets.
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http://dx.doi.org/10.1242/jeb.242446DOI Listing
July 2021

The Effect of Solutions Containing Extracts of Vochysia tucanorum Mart., Myrcia bellaCambess., Matricaria chamomilla L. and Malva sylvestris L. on Cariogenic Bacterial Species and Enamel Caries Development.

Caries Res 2021 17;55(3):193-204. Epub 2021 May 17.

Department of Cariology, Endodontology, and Periodontology, University of Leipzig, Leipzig, Germany.

This study evaluated the effect of experimental solutions containing plant extracts on bacterial species and enamel caries prevention. Microcosm biofilm was produced from human saliva mixed with McBain saliva (0.2% sucrose) on bovine enamel for 5 days (3 days under anaerobiosis and 2 days under aerobiosis) at 37°C. From the 2nd day, the following treatments were applied (1 × 60 s/day): Vochysia tucanorum (10 mg/mL); Myrcia bella (5 mg/mL); Matricaria chamomilla (80 mg/mL); Malva sylvestris, fluoride, and xylitol (Malvatricin Plus®); 0.12% chlorhexidine (CHX, PerioGard®); and PBS (negative control). The medium pH was measured. Quantitative polymerase chain reaction was performed for the detection of Streptococcus mutans and Lactobacillus spp. Enamel demineralization was measured by spectral-domain optical coherence tomography. The data were compared by means of the Kruskal-Wallis/Dunn, two-way ANOVA/Bonferroni, and ANOVA/Tukey tests (p < 0.05). The pH decreased after sucrose exposure; only CHX reestablished pH >5.5 by the last day. CHX also eliminated Lactobacillusspp., but the other treatments did not differ significantly from PBS. Malvatricin Plus® and CHX eliminated S. mutans, but the other treatments did not differ from PBS. Similar results were seen concerning the reduction of lesion depth and reflectivity. The experimental natural-extract solutions were ineffective against cariogenic bacteria and in preventing the development of enamel caries.
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http://dx.doi.org/10.1159/000515234DOI Listing
June 2021

Dental wear patterns reveal dietary ecology and season of death in a historical chimpanzee population.

PLoS One 2021 10;16(5):e0251309. Epub 2021 May 10.

Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.

Dental wear analyses have been widely used to interpret the dietary ecology in primates. However, it remains unclear to what extent a combination of wear analyses acting at distinct temporal scales can be beneficial in interpreting the tooth use of primates with a high variation in their intraspecific dietary ecology. Here, we combine macroscopic tooth wear (occlusal fingerprint analysis, long-term signals) with microscopic 3D surface textures (short-term signals) exploring the tooth use of a historical western chimpanzee population from northeastern Liberia with no detailed dietary records. We compare our results to previously published tooth wear and feeding data of the extant and continually monitored chimpanzees of Taї National Park in Ivory Coast. Macroscopic tooth wear results from molar wear facets of the Liberian population indicate only slightly less wear when compared to the Taї population. This suggests similar long-term feeding behavior between both populations. In contrast, 3D surface texture results show that Liberian chimpanzees have many and small microscopic wear facet features that group them with those Taї chimpanzees that knowingly died during dry periods. This coincides with historical accounts, which indicate that local tribes poached and butchered the Liberian specimens during dust-rich dry periods. In addition, Liberian females and males differ somewhat in their 3D surface textures, with females having more microscopic peaks, smaller hill and dale areas and slightly rougher wear facet surfaces than males. This suggests a higher consumption of insects in Liberian females compared to males, based on similar 3D surface texture patterns previously reported for Taї chimpanzees. Our study opens new options for uncovering details of feeding behaviors of chimpanzees and other living and fossil primates, with macroscopic tooth wear tracing the long-term dietary and environmental history of a single population and microscopic tooth wear addressing short-term changes (e.g. seasonality).
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0251309PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8109778PMC
May 2021

Volumetric measurements of paranasal sinuses and examination of sinonasal communication in healthy Shetland ponies: anatomical and morphometric characteristics using computed tomography.

BMC Vet Res 2021 Jan 21;17(1):41. Epub 2021 Jan 21.

Department for Horses, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 21, D-04103, Leipzig, Germany.

Background: Despite clinical importance and frequent occurrence of sinus disease, little is known about the size of paranasal sinuses and their communication in ponies and small horses. To examine the shape and volume of the paranasal sinuses and evaluate the sinonasal communication, three-dimensional (3D) reconstructions of computed tomography (CT) datasets of 12 healthy adult Shetland ponies were performed and analysed. Linear measurements of head length and width were taken. Using semi-automatic segmentation, 3D-models of all sinus compartments were created. Volumetric measurement of the seven sinus compartments were conducted and statistical analysis was performed. Sinus volumes were compared between the left and right sinuses and the relation to age and head size was evaluated.

Results: Structure and shape of the paranasal sinus system in Shetland ponies was similar to that of large horses. All seven sinus compartments on each side of the head were identified (rostral maxillary sinus, ventral conchal sinus, caudal maxillary sinus, dorsal conchal sinus, middle conchal sinus, frontal sinus, sphenopalatine sinus). The existence of a bilateral cranial and a caudal system formed by a maxillary septum was visible in all 12 individuals. The volumetric sizes of the left and right sinuses did not differ significantly (p > 0.05). A positive correlation between the size of the paranasal sinuses and the head length was shown. A relation between sinus volumes and age could not be proved in adult ponies aged > six years. Communication between single sinus compartments was identified. Furthermore, communication with the nasal cavity over the nasomaxillary aperture (Apertura nasomaxillaris) and a common sinonasal channel (Canalis sinunasalis communis) as well as its splitting up into a rostral and a caudolateral channel could be seen. Examination of the sinonasal communication was challenging and only a descriptive evaluation was possible.

Conclusions: Our findings concerning the size, shape and volumetric dimensions of Shetland pony CT images could help improve CT interpretation of abnormal clinical cases as well as aiding clinicians to develop and select appropriate instruments for medical inspection and treatments.
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http://dx.doi.org/10.1186/s12917-021-02748-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7818571PMC
January 2021

Pharmacokinetics and pharmacodynamics of l-methadone in isoflurane-anaesthetized and mechanically ventilated ponies.

Vet Anaesth Analg 2021 Mar 9;48(2):213-222. Epub 2020 Dec 9.

Clinical Unit of Anaesthesiology and Perioperative Intensive-Care Medicine, Vetmeduni Vienna, Vienna, Austria.

Objective: To evaluate the pharmacokinetics and selected pharmacodynamic effects of a commercially available l-methadone/fenpipramide combination administered to isoflurane anaesthetized ponies.

Study Design: Prospective single-group interventional study.

Animals: A group of six healthy adult research ponies (four mares, two geldings).

Methods: Ponies were sedated with intravenous (IV) detomidine (0.02 mg kg) and butorphanol (0.01 mg kg) for an unrelated study. Additional IV detomidine (0.004 mg kg) was administered 85 minutes later, followed by induction of anaesthesia using IV diazepam (0.05 mg kg) and ketamine (2.2 mg kg). Anaesthesia was maintained with isoflurane in oxygen. Baseline readings were taken after 15 minutes of stable isoflurane anaesthesia. l-Methadone (0.25 mg kg) with fenpipramide (0.0125 mg kg) was then administered IV. Selected cardiorespiratory variables were recorded every 10 minutes and compared to baseline using the Wilcoxon signed-rank test. Adverse events were recorded. Arterial plasma samples for analysis of plasma concentrations and pharmacokinetics of l-methadone were collected throughout anaesthesia at predetermined time points. Data are shown as mean ± standard deviation or median and interquartile range (p < 0.05).

Results: Plasma concentrations of l-methadone showed a rapid initial distribution phase followed by a slower elimination phase which is best described with a two-compartment model. The terminal half-life was 44.3 ± 18.0 minutes, volume of distribution 0.43 ± 0.12 L kg and plasma clearance 7.77 ± 1.98 mL minute kg. Mean arterial blood pressure increased from 85 (±16) at baseline to 100 (±26) 10 minutes after l-methadone/fenpipramide administration (p = 0.031). Heart rate remained constant. In two ponies fasciculations occurred at different time points after l-methadone administration.

Conclusions And Clinical Relevance: Administration of a l-methadone/fenpipramide combination to isoflurane anaesthetized ponies led to a transient increase in blood pressure without concurrent increases in heart rate. Pharmacokinetics of l-methadone were similar to those reported for conscious horses administered racemic methadone.
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http://dx.doi.org/10.1016/j.vaa.2020.04.018DOI Listing
March 2021

An anatomical study of the dorsal and ventral nasal conchal bullae and middle nasal conchae in normal Shetland ponies: Computed tomographic anatomical and morphometric findings.

Anat Histol Embryol 2021 May 16;50(3):431-438. Epub 2020 Dec 16.

Max Planck Institute for Evolutionary Anthropology, Max Planck Weizmann Center for Integrative Archaeology and Anthropology (MPWC), Leipzig, Germany.

Equine paranasal sinuses are susceptible to inflammation. Insufficient drainage through the nasal passages and meatus may lead to the accumulation of inspissated purulent discharge. Particularly in ponies, these anatomical structures are suspected to be relatively small. To date, there are no reports considering the morphology of nasal conchal bullae in small horse breeds such as Shetland ponies. The aim of the present study was to evaluate the size of the conchal bullae and the medial nasal conchae of Shetland ponies and their relation to the skull dimension using computed tomography. Reconstructed images of healthy adult heads of Shetland ponies were used. Linear skull measurements as well as two cranial indices of the head dimensions were taken. Length, width and height of the dorsal and ventral conchal bullae and the medial nasal conchae were measured in relation to the skull and compared with the data of skulls of large breed horses. The anatomical proportions of pony heads were characterized by a smaller cranial index and a greater nasal index than those of large breed horses. Shetland ponies showed a longer cranial length compared with the nasal length. Heads are consistently smaller, and the relationship of the bullae to the head length was also smaller than those measured in large breed horses. A negative correlation between the head and bullae size was found. In conclusion, this study suggests that Shetland ponies have distinguishing proportions of the head. These findings are relevant for clinical examination and surgical treatment of equine sinus disease in those breeds.
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http://dx.doi.org/10.1111/ahe.12646DOI Listing
May 2021

Movement analysis of primate molar teeth under load using synchrotron X-ray microtomography.

J Struct Biol 2021 03 15;213(1):107658. Epub 2020 Nov 15.

Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max-Planck-Institute for Evolutionary Anthropology, 04103 Leipzig, Germany. Electronic address:

Mammalian teeth have to sustain repetitive and high chewing loads without failure. Key to this capability is the periodontal ligament (PDL), a connective tissue containing a collagenous fibre network which connects the tooth roots to the alveolar bone socket and which allows the teeth to move when loaded. It has been suggested that rodent molars under load experience a screw-like downward motion but it remains unclear whether this movement also occurs in primates. Here we use synchroton micro-computed tomography paired with an axial loading setup to investigate the form-function relationship between tooth movement and the morphology of the PDL space in a non-human primate, the mouse lemur (Microcebus murinus). The loading behavior of both mandibular and maxillary molars showed a three-dimensional movement with translational and rotational components, which pushes the tooth into the alveolar socket. Moreover, we found a non-uniform PDL thickness distribution and a gradual increase in volumetric proportion of the periodontal vasculature from cervical to apical. Our results suggest that the PDL morphology may optimize the three-dimensional tooth movement to avoid high stresses under loading.
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http://dx.doi.org/10.1016/j.jsb.2020.107658DOI Listing
March 2021

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

Proc Natl Acad Sci U S A 2020 09 24;117(36):22264-22273. Epub 2020 Aug 24.

Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland.

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.
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http://dx.doi.org/10.1073/pnas.2008149117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7486718PMC
September 2020

Zinc isotopes in Late Pleistocene fossil teeth from a Southeast Asian cave setting preserve paleodietary information.

Proc Natl Acad Sci U S A 2020 03 18;117(9):4675-4681. Epub 2020 Feb 18.

Institut für Geowissenschaften, Arbeitsgruppe für Angewandte und Analytische Paläontologie, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany.

Stable carbon and nitrogen isotope ratios of collagen from bone and dentin have frequently been used for dietary reconstruction, but this method is limited by protein preservation. Isotopes of the trace element zinc (Zn) in bioapatite constitute a promising proxy to infer dietary information from extant and extinct vertebrates. The Zn/Zn ratio (expressed as δZn value) shows an enrichment of the heavy isotope in mammals along each trophic step. However, preservation of diet-related δZn values in fossil teeth has not been assessed yet. Here, we analyzed enamel of fossil teeth from the Late Pleistocene (38.4-13.5 ka) mammalian assemblage of the Tam Hay Marklot (THM) cave in northeastern Laos, to reconstruct the food web and assess the preservation of original δZn values. Distinct enamel δZn values of the fossil taxa (δZn < δZn < δZn) according to their expected feeding habits were observed, with a trophic carnivore-herbivore spacing of +0.60‰ and omnivores having intermediate values. Zn and trace element concentration profiles similar to those of modern teeth also indicate minimal impact of diagenesis on the enamel. While further work is needed to explore preservation for settings with different taphonomic conditions, the diet-related δZn values in fossil enamel from THM cave suggest an excellent long-term preservation potential, even under tropical conditions that are well known to be adverse for collagen preservation. Zinc isotopes could thus provide a new tool to assess the diet of fossil hominins and associated fauna, as well as trophic relationships in past food webs.
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http://dx.doi.org/10.1073/pnas.1911744117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7060694PMC
March 2020

Elevated activity levels do not influence extrinsic fiber attachment morphology on the surface of muscle-attachment sites.

J Anat 2020 05 16;236(5):827-839. Epub 2019 Dec 16.

Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.

Extrinsic fibers (EFs) are a type of penetrating collagenous fiber, closely related to the periodontal ligament, which help anchor soft tissue into bone. These fibers are associated with muscle attachment sites (entheses). Their size and grouping patterns are thought to be indicative of the loading history of the muscle. EFs are of particular significance in anthropology as potential tools for the reconstruction of behavior from skeletal remains and, specifically, entheses. In this study, we used a mouse model to experimentally test how activity level alters the morphology of EF insertion sites on the bone surface of a fibrocartilaginous enthesis, the biceps brachii insertion. Further, we adapted surface metrological techniques from studies of dental wear to perform automated, quantitative and non-destructive analysis of bone surface histology. Our results show that experimentally increased activity had no significant effect on the quantity or density of EF insertions at the enthesis, nor on the size of those insertions. Although EF presence does indicate muscle attachment, activity did not have an observable effect on EF morphology.
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http://dx.doi.org/10.1111/joa.13137DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7163791PMC
May 2020

Complementary approaches to tooth wear analysis in Tritylodontidae (Synapsida, Mammaliamorpha) reveal a generalist diet.

PLoS One 2019 25;14(7):e0220188. Epub 2019 Jul 25.

Institut für Geowissenschaften und Meteorologie, Universität Bonn, Bonn, Germany.

Stereoscopic microwear and 3D surface texture analyses on the cheek teeth of ten Upper Triassic to Lower Cretaceous tritylodontid (Mammaliamorpha) taxa of small/medium to large body size suggest that all were generalist feeders and none was a dietary specialist adapted to herbivory. There was no correspondence between body size and food choice. Stereomicroscopic microwear analysis revealed predominantly fine wear features with numerous small pits and less abundant fine scratches as principal components. Almost all analyzed facets bear some coarser microwear features, such as coarse scratches, large pits, puncture pits and gouges pointing to episodic feeding on harder food items or exogenous effects (contamination of food with soil grit and/or dust), or both. 3D surface texture analysis indicates predominantly fine features with large void volume, low peak densities, and various stages of roundness of the peaks. We interpret these features to indicate consumption of food items with low to moderate intrinsic abrasiveness and can exclude regular rooting, digging or caching behavior. Possible food items include plant vegetative parts, plant reproductive structures (seeds and seed-bearing organs), and invertebrates (i.e., insects). Although the tritylodontid tooth morphology and auto-occlusion suggest plants as the primary food resource, our results imply a wider dietary range including animal matter.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0220188PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6658083PMC
March 2020

Dental microwear texture reflects dietary tendencies in extant Lepidosauria despite their limited use of oral food processing.

Proc Biol Sci 2019 05;286(1903):20190544

1 Applied and Analytical Palaeontology, Institute of Geosciences, Johannes Gutenberg University , J.-J.-Becher-Weg 21, 55128 Mainz , Germany.

Lepidosauria show a large diversity in dietary adaptations, both among extant and extinct tetrapods. Unlike mammals, Lepidosauria do not engage in sophisticated mastication of their food and most species have continuous tooth replacement, further reducing the wear of individual teeth. However, dietary tendency estimation of extinct lepidosaurs usually rely on tooth shape and body size, which allows only for broad distinction between faunivores and herbivores. Microscopic wear features on teeth have long been successfully applied to reconstruct the diet of mammals and allow for subtle discrimination of feeding strategies and food abrasiveness. Here, we present, to our knowledge, the first detailed analysis of dental microwear texture on extant lepidosaurs using a combination of 46 surface texture parameters to establish a framework for dietary tendency estimation of fossil reptilian taxa. We measured dental surface textures of 77 specimens, belonging to herbivorous, algaevorous, frugivorous, carnivorous, ovivorous, insectivorous, molluscivorous, as well as omnivorous species. Carnivores show low density and shallow depth of furrows, whereas frugivores are characterized by the highest density of furrows. Molluscivores show the deepest wear features and highest roughness, herbivores have lower surface roughness and shallower furrows compared to insectivores and omnivores, which overlap in all parameters. Our study shows that despite short food-tooth interaction, dental surface texture parameters enable discrimination of several feeding strategies in lepidosaurs. This result opens new research avenues to assess diet in a broad variety of extant and extinct non-mammalian taxa including dinosaurs and early synapsids.
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http://dx.doi.org/10.1098/rspb.2019.0544DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6545078PMC
May 2019

Dust affects chewing efficiency and tooth wear in forest dwelling Western chimpanzees (Pan troglodytes verus).

Am J Phys Anthropol 2019 05 1;169(1):66-77. Epub 2019 Mar 1.

Max Planck Institute for Evolutionary Anthropology, Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Leipzig, Germany.

Objectives: In humans it has been shown that abrasive particles in the diet result in increased tooth wear and less intense chewing behavior, both of which decrease chewing efficiency. This behavioral response may also exist in non-human primates as a means to reduce the wear effect of dust-laden food. Here we tested whether the periodical occurrence of abrasive dust particles in the diet of Western chimpanzees affects tooth wear and reduces chewing efficiency.

Materials And Methods: We measured fecal particle size of undigested food matter as an indicator of chewing efficiency in 13 Western chimpanzees of the Taï National Park (Ivory Coast) before (wet), after (wet) and during a dust-rich (dry) period. Moreover, feeding data were compiled for a further 12 chimpanzees and matched to three-dimensional surface texture data measured on two molar facets of 26 skulls of the same population.

Results: Fecal particles were larger during the dry period, indicating a reduced chewing efficiency compared to wet periods; age and sex did not have an effect. Concomitantly, dust led to an increase of abrasive wear evidenced by smaller texture features and higher density of fine furrows on wear facets.

Discussion: Our findings show that a periodical increase in dust loads on foods places a dietary-physiological stress on the digestive system in chimpanzees. We suggest that the impact of extrinsic abrasive particles from globally acting periodical dust-laden winds may affect evolutionary fitness. Further studies are required to elucidate this relationship in other non-human primates and fossil hominins.
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http://dx.doi.org/10.1002/ajpa.23808DOI Listing
May 2019

Forage silica and water content control dental surface texture in guinea pigs and provide implications for dietary reconstruction.

Proc Natl Acad Sci U S A 2019 01 3;116(4):1325-1330. Epub 2019 Jan 3.

Applied and Analytical Paleontology, Institute of Geosciences, Johannes Gutenberg University, 55128 Mainz, Germany.

Recent studies have shown that phytoliths are softer than dental enamel but still act as abrasive agents. Thus, phytolith content should be reflected in dental wear. Because native phytoliths show lower indentation hardness than phytoliths extracted by dry ashing, we propose that the hydration state of plant tissue will also affect dental abrasion. To assess this, we performed a controlled feeding experiment with 36 adult guinea pigs, fed exclusively with three different natural forages: lucerne, timothy grass, and bamboo with distinct phytolith/silica contents (lucerne < grass < bamboo). Each forage was fed in fresh or dried state for 3 weeks. We then performed 3D surface texture analysis (3DST) on the upper fourth premolar. Generally, enamel surface roughness increased with higher forage phytolith/silica content. Additionally, fresh and dry grass feeders displayed differences in wear patterns, with those of fresh grass feeders being similar to fresh and dry lucerne (phytolith-poor) feeders, supporting previous reports that "fresh grass grazers" show less abrasion than unspecialized grazers. Our results demonstrate that not only phytolith content but also properties such as water content can significantly affect plant abrasiveness, even to such an extent that wear patterns characteristic for dietary traits (browser-grazer differences) become indistinguishable.
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http://dx.doi.org/10.1073/pnas.1814081116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6347716PMC
January 2019

The phylogenetic signal in tooth wear: What does it mean?

Ecol Evol 2018 Nov 9;8(22):11359-11362. Epub 2018 Oct 9.

Department of Computer Science and Finnish Museum of Natural History University of Helsinki Helsinki Finland.

A new study by Fraser et al (2018) urges the use of phylogenetic comparative methods, whenever possible, in analyses of mammalian tooth wear. We are concerned about this for two reasons. First, this recommendation may mislead the research community into thinking that phylogenetic signal is an artifact of some sort rather than a fundamental outcome of the evolutionary process. Secondly, this recommendation may set a precedent for editors and reviewers to enforce phylogenetic adjustment where it may unnecessarily weaken or even directionally alter the results, shifting the emphasis of analysis from common patterns manifested by large clades to rare cases.
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http://dx.doi.org/10.1002/ece3.4541DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6262935PMC
November 2018

Root growth compensates for molar wear in adult goats (Capra aegagrus hircus).

J Exp Zool A Ecol Integr Physiol 2019 02 4;331(2):139-148. Epub 2018 Dec 4.

Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurih, Zurich, Switzerland.

One reason for the mammalian clade's success is the evolutionary diversity of their teeth. In herbivores, this is represented by high-crowned teeth evolved to compensate for wear caused by dietary abrasives like phytoliths and grit. Exactly how dietary abrasives wear teeth is still not understood completely. We fed four different pelleted diets of increasing abrasiveness (L: Lucerne; G: grass; GR: grass and rice husks; GRS: grass, rice husks, and sand) to four groups of a total of 28 adult goats, all with completely erupted third molars, over a six-month period. Tooth morphology was captured by medical computed tomography scans at the beginning and end of the controlled feeding experiment, and separation lines between the crown and root segments were defined in the upper right second molar (M2), to gauge absolute wear. Using bootstrapping, significant differences in volume loss between diets L/G and GR/GRS were detected. A small but nevertheless consistent volume gain was noted in the roots, and there was a significant, positive correlation between crown volume loss and root volume gain. This growth could possibly be attributed to the well-known process of cementum deposition and its relation with a putative feedback mechanism, in place to attenuate wear caused by abrasive diets.
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http://dx.doi.org/10.1002/jez.2248DOI Listing
February 2019

Time wears on: Assessing how bone wears using 3D surface texture analysis.

PLoS One 2018 7;13(11):e0206078. Epub 2018 Nov 7.

Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.

Use-wear analysis provides a means of studying traces produced on animal bone during manufacture and use in an effort to reconstruct these processes. Often, these analyses are qualitative and based on experience and expertise. Previous studies have focused on interpreting final traces, but little is known about how these traces develop and change over time. We propose the use of an innovative quantitative method for studying bone surface traces that aims to reduce any unreliable or non-replicable results that can confound more traditional qualitative analyses. We seek to understand the basics of use-wear formation over Time by taking incremental molds of bone specimens subjected to a controlled, mechanical experiment. This study assesses how bone wears during extended use on three Material types (fresh skin, processed leather, or dry bark), from three initial Manufacturing states (unworked, ground with sandstone, or scraped with flint). With data obtained from a confocal disc-scanning microscope, we then apply 3D surface texture analysis using ISO 25178 parameters: surface roughness [Sa], autocorrelation length [Sal], peak curvature [Spc], and upper material ratio [Smr1]. We employ a multilevel multivariate Bayesian model to explain parameter variation under experimental conditions. Our findings show how duration of use strongly affects the transformation of the bone's surface. Unworked bone is completely distinguishable from bone used for long time intervals and those modified by scraping. Interestingly, material wear does not often produce type-specific traces, but does affect the rate of bone alteration and how it is transformed. Specifically, fresh skin transforms bone at a faster rate than other materials. This novel quantitative and experimental approach enhances our understanding of the use of bone as a raw material for making and using tools and provides a foundation for future exploration of archaeological materials and questions.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0206078PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6221309PMC
April 2019

Controlled feeding experiments with diets of different abrasiveness reveal slow development of mesowear signal in goats ().

J Exp Biol 2018 10 31;221(Pt 21). Epub 2018 Oct 31.

Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland.

Dental mesowear is applied as a proxy to determine the general diet of mammalian herbivores based on tooth-cusp shape and occlusal relief. Low, blunt cusps are considered typical of grazers and high, sharp cusps typical of browsers. However, how internal or external abrasives impact mesowear, and the time frame the wear signature takes to develop, still need to be explored. Four different pelleted diets of increasing abrasiveness (lucerne, grass, grass and rice husks, and grass, rice husks and sand) were fed to four groups of a total of 28 adult goats in a controlled feeding experiment over a 6-month period. Tooth morphology was captured by medical CT scans at the beginning and end of the experiment. These scans, as well as the crania obtained post mortem, were scored using the mesowear method. Comparisons between diet groups showed few significant differences after 6 months, irrespective of whether CT scans or the real teeth were scored. Only when assessing the difference in signal between the beginning and the end of the experiment did relevant, significant diet-specific effects emerge. Diets containing lower phytolith content caused a more pronounced change in mesowear towards sharper cusps/higher reliefs, while the feed containing sand did not result in more extreme changes in mesowear when compared with the same feed without sand. Our experiment suggests that the formation of a stable and hence reliable mesowear signal requires more time to develop than 6 months.
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http://dx.doi.org/10.1242/jeb.186411DOI Listing
October 2018

Tooth wear as a means to quantify intra-specific variations in diet and chewing movements.

Sci Rep 2016 Sep 23;6:34037. Epub 2016 Sep 23.

Biogéosciences - UMR CNRS 6282, Université Bourgogne Franche Comté et École Pratique des Hautes Études, PSL Research University, Dijon, France.

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 intra-specific 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.
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http://dx.doi.org/10.1038/srep34037DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5034321PMC
September 2016

Tooth wear patterns in black rats (Rattus rattus) of Madagascar differ more in relation to human impact than to differences in natural habitats.

Ecol Evol 2016 04 2;6(7):2205-15. Epub 2016 Mar 2.

Center of Natural History (CeNak) University of Hamburg Hamburg Germany; Max Planck Weizmann Center for Integrative Archaeology and Anthropology Max Planck Institute for Evolutionary Anthropology Leipzig Germany.

Dietary characteristics and environmental variables are important selective factors directing ecological diversification in rodents. On Madagascar, the introductions and spread of the commensal black rat (Rattus rattus) can be seen as example cases to study dietary niche occupation and dietary adaptation in an insular environment. We investigate how tooth wear as a measure of dietary adaptation of black rats differs between four distinct habitats (village, manioc fields, spiny forest, and rainforest) with different dietary resources. We use the 3D surface texture analysis (3DST, using 30 parameters according to ISO 25178) as a measure of dietary abrasiveness. 3DST is applied on the occlusal surface of the upper first molar of 37 black rat specimens. The rainforest sample displays less rough and less voluminous surface textures compared to the village samples as indicated by smaller values for height parameters (Sa, Sp, Sq), inverse areal material ratio (Smc), and volume parameters (Vm, Vmc, Vmp, Vv, and Vvc). We therefore rank sampling areas from highest to lowest abrasiveness (village>manioc fields/spiny forest>rainforest). The rats from villages and rainforest differ to such an extent that one could have interpreted them to belong to different species. This indicates a high degree of variability in terms of ingesta abrasiveness. Furthermore, the pronounced difference between rats from human habitations compared to rats from associated fields or natural vegetation is interpreted to clearly indicate shifts in dietary niche occupation in relation to human impact.
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http://dx.doi.org/10.1002/ece3.2048DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4782253PMC
April 2016
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