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Sterkenburgh TR, Hartl B, Peham C, Nowak M, Kyllar M, Kau S. Temporomandibular joint biomechanics and equine incisor occlusal plane maintenance. Front Bioeng Biotechnol 2023; 11:1249316. [PMID: 37799811 PMCID: PMC10549988 DOI: 10.3389/fbioe.2023.1249316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 08/21/2023] [Indexed: 10/07/2023] Open
Abstract
In equine dentistry, the physiological incisor occlusal surface is visually perceived as a plane with a distinct inclination to the head's coronal plane, extending rostro-ventrally to caudo-dorsally. To better understand the formation of this inclined plane and its connection to dental wear, we investigated the hypothesis that it arises from masticatory movements and the considerable distance between mandibular articular heads and the incisor occlusal surfaces, acting as the three points of support for the mandibles. Leveraging data from a large-scale clinical study involving static and dynamic orthodontic measurements in horses, we approximated the mandibular movement range where incisor occlusion and dental wear occur. By introducing and testing a segment coordinate system, we explored possible angular deviations from the occlusal plane caused by mandibular roll and pitch rotations during two lateral mandibular movement patterns, protrusion and retrusion. Theoretical biomechanical calculations and simulations confirmed the visual perception of the incisor occlusal surface as a plane. To further examine our assumptions, we employed a simple mechanical simulator to assess incisor normal occlusion and provoked malocclusions (diagonal, smile, and frown bite) by modifying temporomandibular joint (TMJ) movement patterns. The results from clinical investigations were corroborated by both the theoretical analysis and mechanical simulations, strengthening our understanding of the biomechanical basis behind the physiological incisor occlusal plane maintenance in horses. These findings have significant implications for equine dental health and contribute to a thorough understanding of TMJ dynamics.
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Affiliation(s)
- Tomas Rudolf Sterkenburgh
- Polyclinic for Dental Preservation and Periodontology, University of Leipzig, Leipzig, Germany
- Department of Industrial Engineering, Business Administration and Statistics, DEGIN Doctoral Program, Universidad Politécnica de Madrid, Madrid, Spain
| | - Bettina Hartl
- Department of Pathobiology, Institute of Morphology, Vetmeduni Vienna, Vienna, Austria
| | - Christian Peham
- Department of Companion Animals and Horses, Movement Science Group, University Clinic for Horses, Vetmeduni Vienna, Vienna, Austria
| | - Michael Nowak
- Veterinary Practice Dr. M. Nowak, Equine Clinic Meerbusch, Meerbusch, Germany
| | - Michal Kyllar
- Department of Pathobiology, Institute of Morphology, Vetmeduni Vienna, Vienna, Austria
| | - Silvio Kau
- Department of Pathobiology, Institute of Morphology, Vetmeduni Vienna, Vienna, Austria
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Saarinen J, Lister AM. Fluctuating climate and dietary innovation drove ratcheted evolution of proboscidean dental traits. Nat Ecol Evol 2023; 7:1490-1502. [PMID: 37580434 PMCID: PMC10482678 DOI: 10.1038/s41559-023-02151-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 07/05/2023] [Indexed: 08/16/2023]
Abstract
Identification of the selective forces that shaped adaptive phenotypes generally relies on current habitat and function, but these may differ from the context in which adaptations arose. Moreover, the fixation of adaptive change in a fluctuating environment and the mechanisms of long-term trends are still poorly understood, as is the role of behaviour in triggering these processes. Time series of fossils can provide evidence on these questions, but examples of individual lineages with adequate fossil and proxy data over extended periods are rare. Here, we present new data on proboscidean dental evolution in East Africa over the past 26 million years, tracking temporal patterns of morphological change in relation to proxy evidence of diet, vegetation and climate (aridity). We show that behavioural experimentation in diet is correlated with environmental context, and that major adaptive change in dental traits followed the changes in diet and environment but only after acquisition of functional innovations in the masticatory system. We partition traits by selective agent, showing that the acquisition of high, multiridged molars was primarily a response to an increase in open, arid environments with high dust accumulation, whereas enamel folding was more associated with the amount of grass in the diet. We further show that long-term trends in these features proceeded in a ratchet-like mode, alternating between directional change at times of high selective pressure and stasis when the selective regime reversed. This provides an explanation for morphology adapted to more extreme conditions than current usage (Liem's Paradox). Our study illustrates how, in fossil series with adequate stratigraphic control and proxy data, environmental and behavioural factors can be mapped on to time series of morphological change, illuminating the mode of acquisition of an adaptive complex.
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Affiliation(s)
- Juha Saarinen
- Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland.
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3
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Clauss M, Codron D, Hummel J. Equid nutritional physiology and behavior: an evolutionary perspective. J Equine Vet Sci 2023; 124:104265. [PMID: 36893821 DOI: 10.1016/j.jevs.2023.104265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 02/18/2023] [Accepted: 02/23/2023] [Indexed: 03/11/2023]
Abstract
Like other members of the even-toed ungulates (the perissodactyls), equids once had a higher species diversity in the fossil record than they have today. This is generally explained in comparison to the enormous diversity of bovid ruminants. Theories on putative competitive disadvantages of equids include the use of a single toe as opposed to two toes per leg, the lack of a specific brain cooling (and hence water-saving) mechanism, longer gestation periods that delay reproductive output, and in particular digestive physiology. To date, there is no empirical support for the theory that equids fare better on low-quality forage than ruminants. In contrast to the traditional juxtaposition of hindgut and foregut fermenters, we suggest that it is more insightful to sketch the evolution of equid and ruminant digestive physiology as a case of convergence: both evolved a particularly high chewing efficacy in their respective groups, which facilitates comparatively high feed and hence energy intakes. But because the ruminant system, less based on tooth anatomy but more on a forestomach sorting mechanism, is more effective, equids depend more on high feed intakes than ruminants and may well be more susceptible to feed shortages. Arguably, the most under-emphasized characteristic of equids may be that in contrast to many other herbivores including ruminants and coprophageous hindgut fermenters, equids do not use the microbial biomass growing in their gastrointestinal tract. Equids display behavioral and morphophysiological adaptations to high feed intakes, and their cranial anatomy that facilitates the cropping of forage while performing grinding chewing at the same time might be unique. Rather than looking for explanations how equids are better adapted to their present niches than other organisms, considering them remnants of a different morphophysiological solution may be more appropriate.
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Affiliation(s)
- Marcus Clauss
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich; 8057 Zurich, Switzerland.
| | - Daryl Codron
- Department of Zoology and Entomology, University of the Free State; Bloemfontein, South Africa.
| | - Jürgen Hummel
- Ruminant Nutrition, Department of Animal Sciences, University of Goettingen; 37077 Goettingen, Germany.
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Stuhlträger J, Kullmer O, Wittig RM, Kupczik K, Schulz-Kornas E. Variability in molar crown morphology and cusp wear in two Western chimpanzee populations. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2023; 181:29-44. [PMID: 36807569 DOI: 10.1002/ajpa.24707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 01/11/2023] [Accepted: 01/24/2023] [Indexed: 02/23/2023]
Abstract
OBJECTIVES Chimpanzees (Pan troglodytes) possess a relatively generalized molar morphology allowing them to access a wide range of foods. Comparisons of crown and cusp morphology among the four subspecies have suggested relatively large intraspecific variability. Here, we compare molar crown traits and cusp wear of two geographically close populations of Western chimpanzees, P. t. verus, to provide further information on intraspecific dental variability. MATERIALS AND METHODS Micro-CT reconstructions of high-resolution replicas of first and second molars of two Western chimpanzee populations from Ivory Coast (Taï National Park) and Liberia, respectively were used for this study. First, we analyzed projected tooth and cusp 2D areas as well as the occurrence of cusp six (C6) on lower molars. Second, we quantified the molar cusp wear three-dimensionally to infer how the individual cusps alter with advancing wear. RESULTS Both populations are similar in their molar crown morphology, except for a higher appearance rate of a C6 in Taï chimpanzees. In Taï chimpanzees, lingual cusps of upper molars and buccal cusps of lower molars possess an advanced wear pattern compared to the remaining cusps, while in Liberian chimpanzees this wear gradient is less pronounced. DISCUSSION The similar crown morphology between both populations fits with previous descriptions for Western chimpanzees and provides additional data on dental variation within this subspecies. The wear pattern of the Taï chimpanzees are in concordance with their observed tool rather than tooth use to open nuts/seeds, while the Liberian chimpanzees may have consumed hard food items crushed between their molars.
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Affiliation(s)
- Julia Stuhlträger
- Former Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Group Animal Husbandry and Ecology, Group Animal Breeding, Institute of Agricultural and Nutritional Sciences, Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Ottmar Kullmer
- Division of Paleoanthropology, Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt am Main, Germany
- Department of Paleobiology and Environment, Institute of Ecology, Evolution, and Diversity, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Roman M Wittig
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Taï Chimpanzee Project, CSRS, Abidjan, Ivory Coast
- Institute for Cognitive Sciences, CNRS UMR5229 University Claude Bernard Lyon 1, Bron, France
| | - Kornelius Kupczik
- Former Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Department of Anthropology, Faculty of Social Sciences, University of Chile, Santiago de Chile, Chile
| | - Ellen Schulz-Kornas
- Former Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Department of Cariology, Endodontics and Periodontology, University of Leipzig, Leipzig, Germany
- Section Mammalogy and Palaeoanthropology, Leibniz Institute for the Analysis of Biodiversity Change and University of Hamburg, Hamburg, Germany
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Abstract
Dental wear due to ingestion of dust and grit has deleterious consequences. Herbivores that could not wash their food hence had to evolve particularly durable teeth, in parallel to the evolution of dental chewing surface complexity to increase chewing efficacy. The rumen sorting mechanism increases chewing efficacy beyond that reached by any other mammal and has been hypothesized to also offer an internal washing mechanism, which would be an outstanding example of an additional advantage by a physiological adaptation, but in vivo evidence is lacking so far. Here, we investigated four cannulated, live cows that received a diet to which sand was added. Silica in swallowed food and feces reflected experimental dietary sand contamination, whereas the regurgitate submitted to rumination remained close to the silica levels of the basal food. This helps explain how ruminants are able to tolerate high levels of dust or grit in their diet, with less high-crowned teeth than nonruminants in the same habitat. Palaeo-reconstructions based on dental morphology and dental wear traces need to take the ruminants' wear-protection mechanism into account. The inadvertent advantage likely contributed to the ruminants' current success in terms of species diversity.
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Martin LF, Winkler DE, Ackermans NL, Müller J, Tütken T, Kaiser T, Codron D, Schulz-Kornas E, Hatt JM, Clauss M. Dental microwear texture analysis correlations in guinea pigs (Cavia porcellus) and sheep (Ovis aries) suggest that dental microwear texture signal consistency is species-specific. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.958576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
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.
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7
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Tamborini M. A Plea for a New Synthesis: From Twentieth-Century Paleobiology to Twenty-First-Century Paleontology and Back Again. BIOLOGY 2022; 11:1120. [PMID: 35892976 PMCID: PMC9394316 DOI: 10.3390/biology11081120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/22/2022] [Accepted: 07/24/2022] [Indexed: 11/16/2022]
Abstract
In this paper, I will briefly discuss the elements of novelty and continuity between twentieth-century paleobiology and twenty-first-century paleontology. First, I will outline the heated debate over the disciplinary status of paleontology in the mid-twentieth century. Second, I will analyze the main theoretical issue behind this debate by considering two prominent case studies within the broader paleobiology agenda. Third, I will turn to twenty-first century paleontology and address five representative research topics. In doing so, I will characterize twenty-first century paleontology as a science that strives for more data, more technology, and more integration. Finally, I will outline what twenty-first-century paleontology might inherit from twentieth-century paleobiology: the pursuit of and plea for a new synthesis that could lead to a second paleobiological revolution. Following in the footsteps of the paleobiological revolution of the 1960s and 1970s, the paleobiological revolution of the twenty-first century would enable paleontologists to gain strong political representation and argue with a decisive voice at the "high table" on issues such as the expanded evolutionary synthesis, the conservation of Earth's environment, and global climate change.
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Affiliation(s)
- Marco Tamborini
- Department of Philosophy, Technische Universität Darmstadt, Marktplatz 15 (Residenzschloss), 64283 Darmstadt, Germany
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8
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Ledogar JA, Senck S, Villmoare BA, Smith AL, Weber GW, Richmond BG, Dechow PC, Ross CF, Grosse IR, Wright BW, Wang Q, Byron C, Benazzi S, Carlson KJ, Carlson KB, Pryor McIntosh LC, van Casteren A, Strait DS. Mechanical compensation in the evolution of the early hominin feeding apparatus. Proc Biol Sci 2022; 289:20220711. [PMID: 35703052 DOI: 10.1098/rspb.2022.0711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Australopiths, a group of hominins from the Plio-Pleistocene of Africa, are characterized by derived traits in their crania hypothesized to strengthen the facial skeleton against feeding loads and increase the efficiency of bite force production. The crania of robust australopiths are further thought to be stronger and more efficient than those of gracile australopiths. Results of prior mechanical analyses have been broadly consistent with this hypothesis, but here we show that the predictions of the hypothesis with respect to mechanical strength are not met: some gracile australopith crania are as strong as that of a robust australopith, and the strength of gracile australopith crania overlaps substantially with that of chimpanzee crania. We hypothesize that the evolution of cranial traits that increased the efficiency of bite force production in australopiths may have simultaneously weakened the face, leading to the compensatory evolution of additional traits that reinforced the facial skeleton. The evolution of facial form in early hominins can therefore be thought of as an interplay between the need to increase the efficiency of bite force production and the need to maintain the structural integrity of the face.
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Affiliation(s)
- Justin A Ledogar
- Department of Health Sciences, East Tennessee State University, Johnson City, TN 37614, USA
| | - Sascha Senck
- Research Group Computed Tomography, University of Applied Sciences Upper Austria, 4600 Wels, Austria
| | - Brian A Villmoare
- Department of Anthropology, University of Nevada, Las Vegas, NV 89154, USA
| | - Amanda L Smith
- Department of Anatomy, Pacific Northwest University of Health Sciences, Yakima, WA 98901, USA
| | - Gerhard W Weber
- Department of Evolutionary Anthropology, University of Vienna, 1030 Vienna, Austria.,Human Evolution and Archaeological Sciences (HEAS), University of Vienna, 1030 Vienna, Austria
| | | | - Paul C Dechow
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, TX 75246, USA
| | - Callum F Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
| | - Ian R Grosse
- Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, MA 01003, USA
| | - Barth W Wright
- Department of Surgery, University of Kansas Medical Center, Kansas City, KS 66106, USA
| | - Qian Wang
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, TX 75246, USA
| | - Craig Byron
- Department of Biology, Mercer University, Macon, GA 31207, USA
| | - Stefano Benazzi
- Department of Cultural Heritage, University of Bologna, Ravenna 48121, Italy
| | - Kristian J Carlson
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.,Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Keely B Carlson
- Department of Anthropology, Texas A&M University, College Station, TX 77843, USA
| | - Leslie C Pryor McIntosh
- Department of Bio-Medical Sciences, Philadelphia College of Osteopathic Medicine South Georgia, Moultrie, GA 31768, USA
| | - Adam van Casteren
- School of Biological Sciences, University of Manchester, Oxford Road, Manchester, UK
| | - David S Strait
- Department of Anthropology, Washington University in St. Louis, St. Louis, MO 63103, USA.,Palaeo-Research Institute, University of Johannesburg, Auckland Park, Johannesburg, Gauteng, South Africa
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9
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TEAFORD MARKF, ROSS CALLUMF, UNGAR PETERS, VINYARD CHRISTOPHERJ, LAIRD MYRAF. Grit your teeth and chew your food: Implications of food material properties and abrasives for rates of dental microwear formation in laboratory Sapajus apella (Primates). PALAEOGEOGRAPHY, PALAEOCLIMATOLOGY, PALAEOECOLOGY 2021; 583:110644. [PMID: 34764513 PMCID: PMC8577397 DOI: 10.1016/j.palaeo.2021.110644] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Dental microwear analysis has been employed in studies of a wide range of modern and fossil animals, yielding insights into the biology/ecology of those taxa. Some researchers have suggested that dental microwear patterns ultimately relate back to the material properties of the foods being consumed, whereas others have suggested that, because exogenous grit is harder than organic materials in food, grit should have an overwhelming impact on dental microwear patterns. To shed light on this issue, laboratory-based feeding experiments were conducted on tufted capuchin monkeys [Sapajus apella] with dental impressions taken before and after consumption of different artificial foods. The foods were (1) brittle custom-made biscuits laced with either of two differently-sized aluminum silicate abrasives, and (2) ductile custom-made "gummies" laced with either of the two same abrasives. In both cases, animals were allowed to feed on the foods for 36 hours before follow-up dental impressions were taken. Resultant casts were analyzed using a scanning electron microscope. We asked five questions: (1) would the animals consume different amounts of each food item, (2) what types of dental microwear would be formed, (3) would rates of dental microwear differ between the consumption of biscuits (i.e., brittle) versus gummies (i.e., ductile), (4) would rates of dental microwear differ between foods including larger- versus smaller-grained abrasives, and (5) would rates of dental microwear differ between molar shearing and crushing facets in the animals in these experiments? Results indicated that (1) fewer biscuits were consumed when laced with larger-grained abrasives (as opposed to smaller-grained abrasives), but no such difference was observed in the consumption of gummies, (2) in all cases, a variety of dental microwear features was formed, (3) rates of dental microwear were higher when biscuits versus gummies were consumed, (4) biscuits laced with larger-grained abrasives caused a higher percentage of new features per item consumed, and (5) the only difference between facets occurred with the processing of biscuits, where crushing facets showed a faster rate of wear than shearing facets. These findings suggest that the impact of exogenous grit on dental microwear is the result of a dynamic, complex interaction between (at the very least) grit size, food material properties, and time spent feeding - which is further evidence of the multifactorial nature of dental microwear formation.
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Affiliation(s)
- MARK F. TEAFORD
- Department of Basic Science, Touro University, Vallejo, California
| | - CALLUM F. ROSS
- Department of Organismal Biology & Anatomy, University of Chicago, Chicago, Illinois
| | - PETER S. UNGAR
- Department of Anthropology, University of Arkansas, Fayetteville, Arkansas
| | | | - MYRA F. LAIRD
- Department of Integrative Anatomical Sciences, University of Southern California, Los Angeles, California
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10
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Krueger KL, Chwa E, Peterson AS, Willman JC, Fok A, van Heel B, Heo Y, Weston M, DeLong R. Technical note: Artificial Resynthesis Technology for the experimental formation of dental microwear textures. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2021; 176:703-712. [PMID: 34405887 DOI: 10.1002/ajpa.24395] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 07/13/2021] [Accepted: 08/02/2021] [Indexed: 11/11/2022]
Abstract
Dental microwear formation on the posterior dentition is largely attributed to an organism's diet. However, some have suggested that dietary and environmental abrasives contribute more to the formation process than food, calling into question the applicability of dental microwear to the reconstruction of diet in the fossil record. Creating microwear under controlled conditions would benefit this debate, but requires accurately replicating the oral environment. This study tests the applicability of Artificial Resynthesis Technology (ART 5) to create microwear textures while mitigating the challenges of past research. ART 5 is a simulator that replicates the chewing cycle, responds to changes in food texture, and simulates the actions of the oral cavity. Surgically extracted, occluding pairs of third molars (n = 2 pairs) were used in two chewing experiments: one with dried beef and another with sand added to the dried beef. High-resolution molds were taken at 0, 50, 100, 2500, and 5000 simulated chewing cycles, which equates to approximately 1 week of chewing. Preliminary results show that ART 5 produces microwear textures. Meat alone may produce enamel prism rod exposure at 5000 cycles, although attrition cannot be ruled out. Meat with sand accelerates the wear formation process, with enamel prism rods quickly obliterated and "pit-and-scratch" microwear forming at approximately 2500 cycles. Future work with ART 5 will incorporate a more thorough experimental protocol with improved controls, pH of the simulated oral environment, and grit measurements; however, these results indicate the potential of ART 5 in untangling the complex variables of dental microwear formation.
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Affiliation(s)
- Kristin L Krueger
- Department of Anthropology, Loyola University Chicago, Chicago, Illinois, USA
| | - Evan Chwa
- College of Dentistry, University of Illinois at Chicago, Chicago, Illinois, USA
| | | | - John C Willman
- Centro de Investigação em Antropologia (CIAS), Universidad de Coimbra, Coimbra, Portugal
| | - Alex Fok
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota School of Dentistry, Minneapolis, Minnesota, USA
| | - Bonita van Heel
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota School of Dentistry, Minneapolis, Minnesota, USA
| | - Young Heo
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota School of Dentistry, Minneapolis, Minnesota, USA
| | - Michael Weston
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota School of Dentistry, Minneapolis, Minnesota, USA
| | - Ralph DeLong
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota School of Dentistry, Minneapolis, Minnesota, USA
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11
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Ackermans NL, Winkler DE, Schulz-Kornas E, Kaiser TM, Martin LF, Hatt JM, Clauss M. Dental wear proxy correlation in a long-term feeding experiment on sheep ( Ovis aries). J R Soc Interface 2021; 18:20210139. [PMID: 34283942 DOI: 10.1098/rsif.2021.0139] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Dietary reconstruction in vertebrates often relies on dental wear-based proxies. Although these proxies are widely applied, the contributions of physical and mechanical processes leading to meso- and microwear are still unclear. We tested their correlation using sheep (Ovis aries, n = 39) fed diets of varying abrasiveness for 17 months as a model. Volumetric crown tissue loss, mesowear change and dental microwear texture analysis (DMTA) were all applied to the same teeth. We hereby correlate: (i) 46 DMTA parameters with each other, for the maxillary molars (M1, M2, M3), and the second mandibular molar (m2); (ii) 10 mesowear variables to each other and to DMTA for M1, M2, M3 and m2; and (iii) volumetric crown tissue loss to mesowear and DMTA for M2. As expected, many DMTA parameters correlated strongly with each other, supporting the application of reduced parameter sets in future studies. Correlation results showed only few DMTA parameters correlated with volumetric tissue change and even less so with mesowear variables, with no correlation between mesowear and volumetric tissue change. These findings caution against interpreting DMTA and mesowear patterns in terms of actual tissue removal until these dental wear processes can be better understood at microscopic and macroscopic levels.
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Affiliation(s)
- Nicole L Ackermans
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland.,Nash Family Department of Neuroscience, Friedman Brain Institute, Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Daniela E Winkler
- Applied and Analytical Paleontology, Institute for Geosciences, Johannes Gutenberg University Mainz, 55099 Mainz, Germany.,Graduate School of Frontier Sciences, Department of Natural Environmental Studies, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563, Japan.,Center of Natural History, University of Hamburg, 20146 Hamburg, Germany
| | - Ellen Schulz-Kornas
- Department of Cariology, Endontology and Peridontology, University of Leipzig, 04103 Leipzig, Germany
| | - Thomas M Kaiser
- Center of Natural History, University of Hamburg, 20146 Hamburg, Germany
| | - Louise F Martin
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland
| | - Jean-Michel Hatt
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland
| | - Marcus Clauss
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland.,AgroVet Strickhof, Lindau Site, Eschikon 27, 8315 Lindau, Switzerland
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12
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Rodriguez-Rojas F, Borrero-Lopez O, Constantino PJ, Henry AG, Lawn BR. Phytoliths can cause tooth wear. J R Soc Interface 2020; 17:20200613. [PMID: 33143592 DOI: 10.1098/rsif.2020.0613] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Comparative laboratory sliding wear tests on extracted human molar teeth in artificial saliva with third-body particulates demonstrate that phytoliths can be as effective as silica grit in the abrasion of enamel. A pin-on-disc wear testing configuration is employed, with an extracted molar cusp as a pin on a hard disc antagonist, under loading conditions representative of normal chewing forces. Concentrations and sizes of phytoliths in the wear test media match those of silica particles. Cusp geometries and ensuing abrasion volumes are measured by digital profilometry. The wear data are considered in relation to a debate by evolutionary biologists concerning the relative capacities of intrinsic mineral bodies within plant tissue and exogenous grit in the atmosphere to act as agents of tooth wear in various animal species.
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Affiliation(s)
- Fernando Rodriguez-Rojas
- Departamento de Ingeniería Mecánica, Energética y de los Materiales, Universidad de Extremadura, 06006 Badajoz, Spain
| | - Oscar Borrero-Lopez
- Departamento de Ingeniería Mecánica, Energética y de los Materiales, Universidad de Extremadura, 06006 Badajoz, Spain
| | - Paul J Constantino
- Department of Biology, Saint Michael's College, Colchester, VT 05439, USA
| | - Amanda G Henry
- Department of Archaeological Sciences, Faculty of Archaeology, Leiden University, 2333CC Leiden, The Netherlands
| | - Brian R Lawn
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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13
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Hua L, Chen J, Ungar PS. Diet reduces the effect of exogenous grit on tooth microwear. BIOSURFACE AND BIOTRIBOLOGY 2020. [DOI: 10.1049/bsbt.2019.0041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Licheng Hua
- School of Mechanical Engineering and MechanicsNingbo UniversityNingbo315211ZhejiangPeople's Republic of China
- Department of AnthropologyUniversity of ArkansasFayettevilleAR72701USA
| | - Jianbin Chen
- School of Mechanical Engineering and MechanicsNingbo UniversityNingbo315211ZhejiangPeople's Republic of China
| | - Peter S. Ungar
- Department of AnthropologyUniversity of ArkansasFayettevilleAR72701USA
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14
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Ackermans NL, Winkler DE, Martin LF, Kaiser TM, Clauss M, Hatt JM. Dust and grit matter: abrasives of different size lead to opposing dental microwear textures in experimentally fed sheep ( Ovis aries). J Exp Biol 2020; 223:jeb220442. [PMID: 31953361 DOI: 10.1242/jeb.220442] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 01/09/2020] [Indexed: 11/20/2022]
Abstract
External abrasives ingested along with the herbivore diet are considered main contributors to dental wear, though how the different sizes and concentrations of these abrasives influence wear remains unclear. Dental microwear texture analysis (DMTA) is an established method for dietary reconstruction which describes a tooth's surface topography on a micrometre scale. The method has yielded conflicting results as to the effect of external abrasives. In the present study, a feeding experiment was performed on sheep (Ovis aries) fed seven diets of different abrasiveness. Our aim was to discern the individual effects of size (4, 50 and 130 µm) and concentration (0%, 4% and 8% of dry matter) of abrasives on dental wear, applying DMTA to four tooth positions. Microwear textures differed between individual teeth, but surprisingly, showed no gradient along the molar tooth row, and the strongest differentiation of experimental groups was achieved when combining data of all maxillary molars. Overall, a pattern of increasing height, volume and complexity of the tooth's microscopic surface appeared with increasing size of dietary abrasives, and when compared with the control, the small abrasive diets showed a polishing effect. The results indicate that the size of dietary abrasives is more important for dental microwear texture traces than their concentration, and that different sizes can have opposing effects on the dietary signal. The latter finding possibly explains conflicting evidence from previous experimental DMTA applications. Further exploration is required to understand whether and how microscopic traces created by abrasives translate quantitatively to tissue loss.
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Affiliation(s)
- Nicole L Ackermans
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, CH-8057 Zurich, Switzerland
| | - Daniela E Winkler
- Applied and Analytical Paleontology, Institute for Geosciences, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
- Center of Natural History, University of Hamburg, 20146 Hamburg, Germany
| | - Louise F Martin
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, CH-8057 Zurich, Switzerland
| | - Thomas M Kaiser
- Center of Natural History, University of Hamburg, 20146 Hamburg, Germany
| | - Marcus Clauss
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, CH-8057 Zurich, Switzerland
| | - Jean-Michel Hatt
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, CH-8057 Zurich, Switzerland
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15
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Teaford MF, Ungar PS, Taylor AB, Ross CF, Vinyard CJ. The dental microwear of hard-object feeding in laboratory Sapajus apella and its implications for dental microwear formation. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 171:439-455. [PMID: 31922261 DOI: 10.1002/ajpa.24000] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 11/23/2019] [Accepted: 12/20/2019] [Indexed: 01/15/2023]
Abstract
OBJECTIVES This study seeks to determine if (a) consumption of hard food items or a mixture of food items leads to the formation of premolar or molar microwear in laboratory capuchin monkeys (Sapajus apella) in one feeding session and (b) rates of microwear formation are associated with the number of food items consumed. MATERIALS AND METHODS Five adult male capuchins were used in two experiments, one where they were fed unshelled Brazil nuts, and the other where they were fed a mixture of food items. Dental impressions were taken before and after each feeding session. Epoxy casts made from those impressions then were used in SEM analyses of rates of microwear formation. Upper and lower premolars and molars were analyzed. Qualitative comparisons were made and Spearman's rank-order correlations used to examine the relationship between rates of microwear formation and number of Brazil nuts consumed. RESULTS Premolars and molars generally showed new microwear in the form of pits and scratches. However, the incidence of those features was low (0-6%). Rates of microwear formation were highest during the consumption of Brazil nuts. DISCUSSION Variations in the rate of microwear formation on the premolars likely reflected patterns of ingestion whereas consistency in the rate of microwear on the molars likely reflected patterns of chewing. While dental microwear formation seemed to be correlated with the number of hard objects consumed, rates did differ between individuals. Differences in results between the two experiments demonstrate some of the limitations in our knowledge of dental microwear formation.
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Affiliation(s)
- Mark F Teaford
- Department of Basic Science, Touro University, Vallejo, California
| | - Peter S Ungar
- Department of Anthropology, University of Arkansas, Fayetteville, Arkansas
| | - Andrea B Taylor
- Department of Basic Science, Touro University, Vallejo, California
| | - Callum F Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois
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16
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Robinet C, Merceron G, Candela AM, Marivaux L. Dental microwear texture analysis and diet in caviomorphs (Rodentia) from the Serra do Mar Atlantic forest (Brazil). J Mammal 2020. [DOI: 10.1093/jmammal/gyz194] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
The Serra do Mar Atlantic forest (Brazil) shelters about 15 different species of caviomorph rodents and thus represents a unique opportunity to explore resource partitioning. We studied 12 species with distinct diets using dental microwear texture analysis (DMTA). Our results revealed differences (complexity, textural fill volume, and heterogeneity of complexity) among species with different dietary preferences, and among taxa sharing the same primary dietary components but not those with similar secondary dietary preferences (heterogeneity of complexity). We found three main dietary tendencies characterized by distinct physical properties: consumers of young leaves had low complexity; bamboo specialists, fruit and seed eaters, and omnivorous species, had intermediate values for complexity; grass, leaf, and aquatic vegetation consumers, had highly complex dental microwear texture. Dietary preferences and body mass explained a major part of the resource partitioning that presumably enables coexistence among these rodent species. DMTA was useful in assessing what foods contributed to resource partitioning in caviomorphs. Our database for extant caviomorph rodents is a prerequisite for interpretation of dental microwear texture of extinct caviomorph taxa, and thus for reconstructing their diets and better understanding the resource partitioning in paleocommunities and its role in the successful evolutionary history of this rodent group.
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Affiliation(s)
- Céline Robinet
- División Paleontología Vertebrados, Museo de La Plata, La Plata, Argentina
| | - Gildas Merceron
- Laboratoire PALEVOPRIM (UMR 7262 CNRS-INEE & Université de Poitiers) Université de Poitiers, Poitiers Cedex, France
| | - Adriana M Candela
- División Paleontología Vertebrados, Museo de La Plata, La Plata, Argentina
| | - Laurent Marivaux
- Laboratoire de Paléontologie, Institut des Sciences de l’Évolution de Montpellier (ISE-M, UMR 5554 CNRS/UM/IRD/EPHE), c.c. 064, Université de Montpellier, Place E. Bataillon, France
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17
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van Casteren A, Crofts SB. The Materials of Mastication: Material Science of the Humble Tooth. Integr Comp Biol 2019; 59:1681-1689. [DOI: 10.1093/icb/icz129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Dental functional morphology, as a field, represents a confluence of materials science and biology. Modern methods in materials testing have been influential in driving the understanding of dental tissues and tooth functionality. Here we present a review of dental enamel, the outermost tissue of teeth. Enamel is the hardest biological tissue and exhibits remarkable resilience even when faced with a variety of mechanical threats. In the light of recent work, we progress the argument that the risk of mechanical degradation across multiple scales exhibits a strong and continued selection pressure on structural organization of enamel. The hierarchical nature of enamel structure presents a range of scale-dependent toughening mechanisms and provides a means by which natural selection can drive the specialization of this tissue from nanoscale reorganization to whole tooth morphology. There has been much learnt about the biomechanics of enamel recently, yet our understanding of the taxonomic diversity of this tissue is still lacking and may form an interesting avenue for future research.
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Affiliation(s)
- Adam van Casteren
- Department of Anthropology, Washington University in St Louis, Campus Box 1114, One Brookings Drive, St Louis, MO 63130, USA
| | - Stephanie B Crofts
- Department of Animal Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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18
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19
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Ackermans NL, Clauss M, Winkler DE, Schulz-Kornas E, Kaiser TM, Müller DWH, Kircher PR, Hummel J, Hatt JM. Root growth compensates for molar wear in adult goats (Capra aegagrus hircus). JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 331:139-148. [PMID: 30511369 DOI: 10.1002/jez.2248] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/09/2018] [Accepted: 11/10/2018] [Indexed: 11/09/2022]
Abstract
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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Affiliation(s)
- Nicole L Ackermans
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurih, Zurich, Switzerland
| | - Marcus Clauss
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurih, Zurich, Switzerland
| | - Daniela E Winkler
- Institute for Geosciences, Johannes Gutenberg University Mainz, Mainz, Germany.,Center of Natural History, University of Hamburg, Hamburg, Germany
| | - Ellen Schulz-Kornas
- Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Center of Natural History, University of Hamburg, Hamburg, Germany
| | - Thomas M Kaiser
- Center of Natural History, University of Hamburg, Hamburg, Germany
| | | | - Patrick R Kircher
- Division of Diagnostic Imaging, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Jürgen Hummel
- Department of Animal Sciences, Ruminant Nutrition, Georg-August-University, Göttingen, Germany
| | - Jean-Michel Hatt
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurih, Zurich, Switzerland
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20
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Ackermans NL, Winkler DE, Schulz-Kornas E, Kaiser TM, Müller DWH, Kircher PR, Hummel J, Clauss M, Hatt JM. Controlled feeding experiments with diets of different abrasiveness reveal slow development of mesowear signal in goats ( Capra aegagrus hircus). ACTA ACUST UNITED AC 2018; 221:jeb.186411. [PMID: 30194251 DOI: 10.1242/jeb.186411] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 09/05/2018] [Indexed: 11/20/2022]
Abstract
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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Affiliation(s)
- Nicole L Ackermans
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland
| | - Daniela E Winkler
- Institute for Geosciences, Johannes Gutenberg University Mainz, 55099 Mainz, Germany.,Center of Natural History, University of Hamburg, 20146 Hamburg, Germany
| | - Ellen Schulz-Kornas
- Center of Natural History, University of Hamburg, 20146 Hamburg, Germany.,Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - Thomas M Kaiser
- Center of Natural History, University of Hamburg, 20146 Hamburg, Germany
| | - Dennis W H Müller
- Zoologischer Garten Halle GmbH, Fasanenstr. 5a, 06114 Halle (Saale), Germany
| | - Patrick R Kircher
- Division of Diagnostic Imaging, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland
| | - Jürgen Hummel
- Department of Animal Sciences, Ruminant Nutrition, Georg-August University, 37073 Göttingen, Germany
| | - Marcus Clauss
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland
| | - Jean-Michel Hatt
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland
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21
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Constantino PJ, Borrero‐Lopez O, Lawn BR. Mechanisms of tooth damage and
Paranthropus
dietary reconstruction. BIOSURFACE AND BIOTRIBOLOGY 2018. [DOI: 10.1049/bsbt.2018.0017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
| | - Oscar Borrero‐Lopez
- Departamento de Ingeniería Mecánica, Energética y de los MaterialesUniversidad de Extremadura06006BadajozSpain
| | - Brian R. Lawn
- Materials Measurement LaboratoryNational Institute of Standards and TechnologyGaithersburgMD20899USA
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22
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Pampush JD, Spradley JP, Morse PE, Griffith D, Gladman JT, Gonzales LA, Kay RF. Adaptive wear-based changes in dental topography associated with atelid (Mammalia: Primates) diets. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly069] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- James D Pampush
- Department of Exercise Science, High Point University, High Point, NC, USA
- Department of Physician Assistant Studies, High Point University, High Point, NC, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
| | - Jackson P Spradley
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Department of Biology and Marine Biology, University of North Carolina at Wilmington, Wilmington, NC, USA
| | - Paul E Morse
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Department of Anthropology, University of Florida, Gainesville, FL, USA
- Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
| | - Darbi Griffith
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
| | - Justin T Gladman
- Shared Materials Instrumentation Facility (SMIF), Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Lauren A Gonzales
- Department of Biomedical Sciences, University of South Carolina School of Medicine Greenville, Greenville, SC, USA
| | - Richard F Kay
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC, USA
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23
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Xia J, Tian ZR, Hua L, Chen L, Zhou Z, Qian L, Ungar PS. Enamel crystallite strength and wear: nanoscale responses of teeth to chewing loads. J R Soc Interface 2018; 14:rsif.2017.0456. [PMID: 29070592 DOI: 10.1098/rsif.2017.0456] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 09/26/2017] [Indexed: 11/12/2022] Open
Abstract
The nanoscale responses of teeth to chewing loads are poorly understood. This has contributed to debate concerning the aetiology of enamel wear and resistance to fracture. Here we develop a new model for reactions of individual hydroxyapatite nanofibres to varying loads and directions of force. Hydroxyapatite nanofibres, or crystallites, composed of chains of bonded nanospheres, are the fundamental building blocks of enamel. This study indicates that these nanofibres respond to contact pressure in three distinct ways depending on force magnitude and direction: (i) plucking (nanosphere loss when the strength of the bonding protein 'glue' is exceeded), (ii) plastic deformation (compression to gradually bend nanofibres and squeeze the protein layer), and (iii) fragmentation (nanofibres fracture when the strength of H-bonds that bind smaller nanoparticles into nanospheres is exceeded). Critical contact pressure to initiate plucking is the lowest, followed by plastic deformation, and then fragmentation. Further, lower contact pressures are required for a response with shear forces applied perpendicular to the long axes of crystallites than with crushing forces parallel to them alone. These nanoscale responses are explained as a function of the interfacial nanochemical bonding between and within individual crystallites. In other words, nanochemistry plays a critical role in the responses of enamel to varying chewing loads.
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Affiliation(s)
- Jing Xia
- Tribology Research Institute, Key Laboratory of Advanced Technologies of Materials, Ministry of Education of China, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
| | - Z Ryan Tian
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA.,Institute of Nanoscale Science and Engineering, University of Arkansas, Fayetteville, AR 72701, USA
| | - Licheng Hua
- Tribology Research Institute, Key Laboratory of Advanced Technologies of Materials, Ministry of Education of China, Southwest Jiaotong University, Chengdu 610031, People's Republic of China.,Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA.,Institute of Nanoscale Science and Engineering, University of Arkansas, Fayetteville, AR 72701, USA
| | - Lei Chen
- Tribology Research Institute, Key Laboratory of Advanced Technologies of Materials, Ministry of Education of China, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
| | - Zhongrong Zhou
- Tribology Research Institute, Key Laboratory of Advanced Technologies of Materials, Ministry of Education of China, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
| | - Linmao Qian
- Tribology Research Institute, Key Laboratory of Advanced Technologies of Materials, Ministry of Education of China, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
| | - Peter S Ungar
- Department of Anthropology, University of Arkansas, Fayetteville, AR 72701, USA
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24
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Peterson A, Abella EF, Grine FE, Teaford MF, Ungar PS. Microwear textures of Australopithecus africanus and Paranthropus robustus molars in relation to paleoenvironment and diet. J Hum Evol 2018; 119:42-63. [DOI: 10.1016/j.jhevol.2018.02.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 02/03/2018] [Accepted: 02/05/2018] [Indexed: 12/20/2022]
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25
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van Casteren A, Lucas PW, Strait DS, Michael S, Bierwisch N, Schwarzer N, Al-Fadhalah KJ, Almusallam AS, Thai LA, Saji S, Shekeban A, Swain MV. Evidence that metallic proxies are unsuitable for assessing the mechanics of microwear formation and a new theory of the meaning of microwear. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171699. [PMID: 29892367 PMCID: PMC5990759 DOI: 10.1098/rsos.171699] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 04/20/2018] [Indexed: 05/14/2023]
Abstract
Mammalian tooth wear research reveals contrasting patterns seemingly linked to diet: irregularly pitted enamel surfaces, possibly from consuming hard seeds, versus roughly aligned linearly grooved surfaces, associated with eating tough leaves. These patterns are important for assigning diet to fossils, including hominins. However, experiments establishing conditions necessary for such damage challenge this paradigm. Lucas et al. (Lucas et al. 2013 J. R. Soc. Interface10, 20120923. (doi:10.1098/rsif.2012.0923)) slid natural objects against enamel, concluding anything less hard than enamel would rub, not abrade, its surface (producing no immediate wear). This category includes all organic plant matter. Particles harder than enamel, with sufficiently angular surfaces, could abrade it immediately, prerequisites that silica/silicate particles alone possess. Xia et al. (Xia, Zheng, Huang, Tian, Chen, Zhou, Ungar, Qian. 2015 Proc. Natl Acad. Sci. USA112, 10 669-10 672. (doi:10.1073/pnas.1509491112)) countered with experiments using brass and aluminium balls. Their bulk hardness was lower than enamel, but the latter was abraded. We examined the ball exteriors to address this discrepancy. The aluminium was surfaced by a thin rough oxide layer harder than enamel. Brass surfaces were smoother, but work hardening during manufacture gave them comparable or higher hardness than enamel. We conclude that Xia et al.'s results are actually predicted by the mechanical model of Lucas et al. To explain wear patterns, we present a new model of textural formation, based on particle properties and presence/absence of silica(tes).
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Affiliation(s)
- Adam van Casteren
- Max Planck Weizmann Center for Integrative Archeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, D-04103, Leipzig, Germany
| | - Peter W. Lucas
- Smithsonian Tropical Research Institute, Luis Clement Ave., Bldg. 401 Tupper Balboa Ancon, Panama, Republic of Panama
| | - David S. Strait
- Department of Anthropology, Washington University in St Louis, Campus Box 1114, One Brookings Drive, St Louis, MO 63130, USA
| | - Shaji Michael
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, PO Box 24923, Safat 11310, Kuwait
| | - Nick Bierwisch
- Saxonian Institute of Surface Mechanics SIO, Tankow 2, 18569 Ummanz, Rügen, Germany
| | - Norbert Schwarzer
- Saxonian Institute of Surface Mechanics SIO, Tankow 2, 18569 Ummanz, Rügen, Germany
| | - Khaled J. Al-Fadhalah
- Department of Mechanical Engineering, College of Engineering and Petroleum, Kuwait University, PO Box 5969, Safat 13060, Kuwait
| | - Abdulwahab S. Almusallam
- Department of Chemical Engineering, College of Engineering and Petroleum, Kuwait University, PO Box 5969, Safat 13060, Kuwait
| | - Lidia A. Thai
- Nanotechnology Research Facility, College of Engineering and Petroleum, Kuwait University, PO Box 5969, Safat 13060, Kuwait
| | - Sreeja Saji
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, PO Box 24923, Safat 11310, Kuwait
| | - Ali Shekeban
- Nanotechnology Research Facility, College of Engineering and Petroleum, Kuwait University, PO Box 5969, Safat 13060, Kuwait
| | - Michael V. Swain
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, PO Box 24923, Safat 11310, Kuwait
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26
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van Casteren A, Lucas PW, Strait DS, Michael S, Bierwisch N, Schwarzer N, Al-Fadhalah KJ, Almusallam AS, Thai LA, Saji S, Shekeban A, Swain MV. Evidence that metallic proxies are unsuitable for assessing the mechanics of microwear formation and a new theory of the meaning of microwear. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171699. [PMID: 29892367 DOI: 10.5061/dryad.72431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 04/20/2018] [Indexed: 05/27/2023]
Abstract
Mammalian tooth wear research reveals contrasting patterns seemingly linked to diet: irregularly pitted enamel surfaces, possibly from consuming hard seeds, versus roughly aligned linearly grooved surfaces, associated with eating tough leaves. These patterns are important for assigning diet to fossils, including hominins. However, experiments establishing conditions necessary for such damage challenge this paradigm. Lucas et al. (Lucas et al. 2013 J. R. Soc. Interface10, 20120923. (doi:10.1098/rsif.2012.0923)) slid natural objects against enamel, concluding anything less hard than enamel would rub, not abrade, its surface (producing no immediate wear). This category includes all organic plant matter. Particles harder than enamel, with sufficiently angular surfaces, could abrade it immediately, prerequisites that silica/silicate particles alone possess. Xia et al. (Xia, Zheng, Huang, Tian, Chen, Zhou, Ungar, Qian. 2015 Proc. Natl Acad. Sci. USA112, 10 669-10 672. (doi:10.1073/pnas.1509491112)) countered with experiments using brass and aluminium balls. Their bulk hardness was lower than enamel, but the latter was abraded. We examined the ball exteriors to address this discrepancy. The aluminium was surfaced by a thin rough oxide layer harder than enamel. Brass surfaces were smoother, but work hardening during manufacture gave them comparable or higher hardness than enamel. We conclude that Xia et al.'s results are actually predicted by the mechanical model of Lucas et al. To explain wear patterns, we present a new model of textural formation, based on particle properties and presence/absence of silica(tes).
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Affiliation(s)
- Adam van Casteren
- Max Planck Weizmann Center for Integrative Archeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, D-04103, Leipzig, Germany
| | - Peter W Lucas
- Smithsonian Tropical Research Institute, Luis Clement Ave., Bldg. 401 Tupper Balboa Ancon, Panama, Republic of Panama
| | - David S Strait
- Department of Anthropology, Washington University in St Louis, Campus Box 1114, One Brookings Drive, St Louis, MO 63130, USA
| | - Shaji Michael
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, PO Box 24923, Safat 11310, Kuwait
| | - Nick Bierwisch
- Saxonian Institute of Surface Mechanics SIO, Tankow 2, 18569 Ummanz, Rügen, Germany
| | - Norbert Schwarzer
- Saxonian Institute of Surface Mechanics SIO, Tankow 2, 18569 Ummanz, Rügen, Germany
| | - Khaled J Al-Fadhalah
- Department of Mechanical Engineering, College of Engineering and Petroleum, Kuwait University, PO Box 5969, Safat 13060, Kuwait
| | - Abdulwahab S Almusallam
- Department of Chemical Engineering, College of Engineering and Petroleum, Kuwait University, PO Box 5969, Safat 13060, Kuwait
| | - Lidia A Thai
- Nanotechnology Research Facility, College of Engineering and Petroleum, Kuwait University, PO Box 5969, Safat 13060, Kuwait
| | - Sreeja Saji
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, PO Box 24923, Safat 11310, Kuwait
| | - Ali Shekeban
- Nanotechnology Research Facility, College of Engineering and Petroleum, Kuwait University, PO Box 5969, Safat 13060, Kuwait
| | - Michael V Swain
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, PO Box 24923, Safat 11310, Kuwait
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Brief communication: Dental microwear and diet of Homo naledi. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 166:228-235. [DOI: 10.1002/ajpa.23418] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 12/07/2017] [Accepted: 01/09/2018] [Indexed: 11/07/2022]
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Teaford MF, Ungar PS, Taylor AB, Ross CF, Vinyard CJ. In vivo rates of dental microwear formation in laboratory primates fed different food items. BIOSURFACE AND BIOTRIBOLOGY 2017. [DOI: 10.1016/j.bsbt.2017.11.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Viranta S, Mannermaa K. A tall rostral hook in a medieval horse premolar tooth. INTERNATIONAL JOURNAL OF PALEOPATHOLOGY 2017; 17:79-81. [PMID: 28521915 DOI: 10.1016/j.ijpp.2017.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 02/17/2017] [Accepted: 02/20/2017] [Indexed: 06/07/2023]
Abstract
Development of dental abnormalities due to improper occlusal wear is common among modern domestic horses. This phenomenon often is attributed to jaw conformation. Rostral mandibular hooks may develop in horses with underjet or mandibular prognathism, a condition where the lower jaw protrudes forward, beyond the upper jaw. Less abrasive diet, free of phytoliths and matrix-like plant fibers, also may promote enamel and focal overgrowths of equine dentition. Here we report a rostral mandibular hook in a lower premolar tooth of a medieval horse, found in a spring deposit in Levänluhta, Osthrobothnia, Finland. To our knowledge, this is the first such report from a medieval horse.
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Affiliation(s)
- Suvi Viranta
- Faculty of Medicine, Anatomy, PO Box 63 (Haartmaninkatu 8), 00014 University of Helsinki, Finland.
| | - Kristiina Mannermaa
- Department of Philosophy, History, Culture and Art Studies/Archaeology, PO Box 59, 00014 University of Helsinki, Finland.
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Dittmann MT, Kreuzer M, Runge U, Clauss M. Ingestive mastication in horses resembles rumination but not ingestive mastication in cattle and camels. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2017; 327:98-109. [PMID: 29356397 DOI: 10.1002/jez.2075] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/13/2017] [Accepted: 04/18/2017] [Indexed: 11/06/2022]
Abstract
Horses achieve a higher degree of particle size reduction through ingestive mastication than functional ruminants. We characterized mastication using chew-monitoring halters (RumiWatch) in six domestic horses, cattle, and Bactrian camels each. All animals were offered grass hay of the same batch for 15 min. In cattle and camels, measurements were continued after eating until rumination was observed. Except for one horse, 96% of the horses' ingestive mastication data were identified as "rumination" by the proprietary RumiWatch algorithm, whereas ingestion and rumination by cattle and camels were mostly classified correctly. There were no systematic differences between cattle and camels. In cattle and camels, ingestive mastication was less regular than rumination, indicated by significantly higher standard deviations of chewing peak intervals, peak heights, and peak breadths in intraindividual comparisons. The average standard deviations of these measures were lower in horses than in cattle and camel ingestive mastication, indicating a more consistent chewing pattern in horses. Horse values were similar to those of rumination mastication, suggesting equally regular chewing motions. Regular, rhythmic chewing represents a common feature of horses and functional ruminants, but the less uniform ingestive mastication in functional ruminants represents a deviating pattern, the adaptive value of which remains unclear. In particular, it does not appear to promote a higher ingestion rate. A potential cause may be the avoidance of high tooth wear rates by delaying a more regular, systematic mastication until ingesta has been softened and the grit has been washed off in the forestomach.
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Affiliation(s)
- Marie T Dittmann
- School of Agriculture, Policy and Development, University of Reading, Earley Gate Reading, United Kingdom.,ETH Zurich, Institute of Agricultural Sciences, Universitätsstr. 2, Zurich, Switzerland.,Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty Zurich, University of Zurich, Zurich, Switzerland
| | - Michael Kreuzer
- ETH Zurich, Institute of Agricultural Sciences, Universitätsstr. 2, Zurich, Switzerland
| | | | - Marcus Clauss
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty Zurich, University of Zurich, Zurich, Switzerland
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