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Gonçalves IMC, da Silva JA, Aguiar FHB, Lima DANL. Development of toothpaste formulations containing mineral clays as abrasive agents and their effects on the physical properties of dental enamel. J ESTHET RESTOR DENT 2024; 36:901-910. [PMID: 38348937 DOI: 10.1111/jerd.13208] [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: 01/29/2024] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 05/08/2024]
Abstract
To assess the physical properties and topographical aspect of dental enamel's surface microhardness (KHN), surface roughness (Ra), and color parameters CIELAB (∆Eab*), CIEDE 2000 (∆E00), and whiteness index for dentistry (∆WID) after toothbrushing with experimental toothpaste formulations with the following mineral clay types: kaolin, Sparclay SGY, and Tersil CGY used as abrasive component. Scanning electron microscopy (SEM) was performed for topographical analyses purposes. A total of 96 bovine incisors were used in the experiment. They were divided into eight experimental groups (n = 12), namely: NC-negative control (no treatment), CT12-Colgate Total 12®, CMP-Colgate® Máxima Proteção Anticáries, K-kaolin experimental toothpaste, SGY-Sparclay SGY experimental toothpaste; CGY-Tersil CGY experimental toothpaste, SD-SiO2 experimental toothpaste, and CC-CaCO3 experimental toothpaste. All samples were subjected to mechanical brushing protocol with 5000 cycles and kept in artificial saliva with daily exchanges. KHN was analyzed through the mixed linear model for repeated measures over time. Ra was analyzed through nonparametric Kruskal Wallis and Dunn tests to compare the groups. Paired Wilcoxon test was run to compare experimental times. ∆WID, ∆Eab*, and ∆E00 were analyzed through Kruskal Wallis and Dunn tests. All analyses were performed in R* software, at 5% significance level. EXP_SGY recorded higher KHN than EXP_SiO2 and EXP_CaCO3, whereas EXP_K showed increased Ra in comparison to CMP (p = 0.0229). ∆Eab and ∆E00 were significantly higher in the CT12, EXP_SiO2, and EXP_CaCO3 groups than in the NC and EXP_K (p < 0.0001). There were no significant changes in ∆WID (p = 0.0852). According to SEM results, toothbrushing with experimental toothpastes added with mineral clay types did not have significant impact on enamel's polishing and smoothness. CLINICAL RELEVANCE: Mineral clays have a broad application in the cosmetic industry, and recently, they have been used in the formulation of vegan toothpaste.
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Affiliation(s)
- Iana Maria Costa Gonçalves
- Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, SP, Brazil
| | - Julliana Andrade da Silva
- Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, SP, Brazil
| | - Flávio Henrique Baggio Aguiar
- Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, SP, Brazil
| | - Débora Alves Nunes Leite Lima
- Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, SP, Brazil
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Winkler DE, Seike H, Nagata S, Kubo MO. Mandible microwear texture analysis of crickets raised on diets of different abrasiveness reveals universality of diet-induced wear. Interface Focus 2024; 14:20230065. [PMID: 38618236 PMCID: PMC11008958 DOI: 10.1098/rsfs.2023.0065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 03/06/2024] [Indexed: 04/16/2024] Open
Abstract
Animals have evolved diverse comminuting tools. While vertebrates possess mineralized teeth, insect mandibles often bear metal-inclusion-hardened serrated cusps. Microscopic dental enamel wear (microwear) is known to be caused by contact with ingesta. To test if insect mandible microwear is also diet-dependent, we kept newly moulted adult two-spotted crickets (Gryllus bimaculatus) for four weeks on alfalfa-based rodent pellets with and without added mineral abrasives (loess, quartz, volcanic ash). Six crickets per diet were examined after 1, 3, 7, 14, 21 and 28 days. All diets induced progressive mandible wear, affecting specific locations along the distal tooth cusps differently. The depth of furrows increased on most abrasive-containing diets until day 21, while wear mark complexity increased from day 1 to 3 and 14 to 21. After 28 days, these parameter values for large volcanic ash and large quartz diets significantly exceeded those for the control diet. These results are comparable to observations from guinea pig feeding experiments with the same diets. Cricket mandible wear was affected by all abrasives. Notably, large volcanic ash and large quartz induced the deepest, most complex lesions, akin to observations in guinea pigs. This suggests a universal wear process, supporting that microwear analyses are suitable for inferring invertebrate diets.
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Affiliation(s)
- Daniela E. Winkler
- Kiel University, Zoological Institute, Zoology and Functional Morphology of Vertebrates, Kiel, Schleswig-Holstein, Germany
- Department of Natural Environmental Studies, The University of Tokyo, Graduate School of Frontier Sciences, Kashiwa, Chiba, Japan
| | - Hitomi Seike
- Department of Integrated Biosciences, The University of Tokyo, Graduate School of Frontier Sciences, Kashiwa, Chiba, Japan
| | - Shinji Nagata
- Department of Integrated Biosciences, The University of Tokyo, Graduate School of Frontier Sciences, Kashiwa, Chiba, Japan
| | - Mugino O. Kubo
- Department of Natural Environmental Studies, The University of Tokyo, Graduate School of Frontier Sciences, Kashiwa, Chiba, Japan
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3
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Martin LF, Codron D, Winkler DE, Tütken T, Hatt JM, Clauss M. Macroscopic dental measures in guinea pigs ( Cavia porcellus) fed natural and pelleted diets of different abrasiveness: implications for wear and compensatory growth in a hypselodont species. J R Soc Interface 2023; 20:20230012. [PMID: 37254702 PMCID: PMC10230326 DOI: 10.1098/rsif.2023.0012] [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: 01/09/2023] [Accepted: 05/10/2023] [Indexed: 06/01/2023] Open
Abstract
The drivers of dental wear and compensatory hypselodont tooth growth are of current research interest. Expanding previous macroscopic dental wear measurements based on microtomographic scans of guinea pigs (Cavia porcellus) fed natural diets, we added diet groups with different predicted drivers of dental wear and analysed how measured variables relate to each other. The teeth of guinea pigs fed either pelleted diets containing external abrasives of various shapes, sizes and percentages (n = 66) or natural whole-leaf diets (n = 36, low-phytolith lucerne or grass or high-phytolith bamboo) were evaluated. The bamboo-fed animals showed the lowest tooth height with deep dentine basins, similar to the pellet-fed animals. Deeper dentine basins generally correlated with higher occlusal surfaces, allowing the hypothesis that changes in the pressure signal due to lower basins could initiate compensatory growth and broadening of the whole tooth surface in hypselodont teeth. Macroscopic dental wear did not categorically differ between whole-leaf or pelleted diets or between diets with internal phytoliths or with external silicate abrasives. Supporting interpretations that tooth wear should be viewed as a response to the biomechanical properties of ingested feed which may or may not be aptly summarized by broad descriptors such as 'whole/pelleted' or 'natural/artificial'.
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Affiliation(s)
- Louise Françoise Martin
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, 8057 Zurich, Switzerland
| | - Daryl Codron
- Department of Zoology and Entomology, University of the Free State, PO Box 339, 9300 Bloemfontein, South Africa
| | - Daniela Eileen Winkler
- Applied and Analytical Palaeontology, Institute of Geosciences, Johannes Gutenberg University, J.-J.-Becher-Weg 21, 55128 Mainz, Germany
- Zoology und Functional Morphology of Vertebrates, Zoological Institute, University Kiel, Am Botanischen Garten 3–9, 24118 Kiel, Germany
| | - Thomas Tütken
- Applied and Analytical Palaeontology, Institute of Geosciences, Johannes Gutenberg University, J.-J.-Becher-Weg 21, 55128 Mainz, Germany
| | - Jean-Michel Hatt
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, 8057 Zurich, Switzerland
| | - Marcus Clauss
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, 8057 Zurich, Switzerland
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Browsing into a Panamanian tropical rainforest: micro- and mesowear study of Central American red brocket deer. MAMMAL RES 2023. [DOI: 10.1007/s13364-023-00676-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
AbstractThe Mazama genus is one of the more diverse genera among deer (Cervidae); its classification is controversial because of its complex phylogenetic relationships. The Central American red brocket deer (Mazama temama) is distributed from Central America to the northwest of South America. Studying the diet of mammals gives us information about the environment in which they live, considering that animals select food according to the resources available in the surrounding environment. Mesowear and microwear provide complementary data because they present direct evidence of feeding behaviour on different time scales. The use of extant animals as control samples or baselines allows for the interpretation of the results of a study performed using the archaeological record. For this reason, the aim of this paper was to study the diet of extant M. temama from Darien and to compare it with our previous results on ancient deer from Pedro Gonzalez Island archaeological site (6060–5620 cal yr BP) and extant individuals from San Jose Island (Panama). Evidence from the meso- and microwear analyses of M. temama from Darien suggests that they were browse-dominated mixed feeders during the last years of their lives and during the days before their death. There was no evidence of seasonal variation in their diets and between sexes. This paper exemplifies the potential of studying extant materials housed in museum collections as a reference to compare them to archaeological remains. The use of the same methods allows to construct baselines to better understand the archaeological record in the Neotropics.
Graphical Abstract
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Multi-proxy dentition analyses reveal niche partitioning between sympatric herbivorous dinosaurs. Sci Rep 2022; 12:20813. [PMID: 36460688 PMCID: PMC9718793 DOI: 10.1038/s41598-022-24816-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022] Open
Abstract
Dentitions of the sympatric herbivorous dinosaurs Hungarosaurus (Ankylosauria, Nodosauridae) and Mochlodon (Ornithopoda, Rhabdodontidae) (Santonian, Hungary) were analysed to investigate their dietary ecology, using several complementary methods-orientation patch count, tooth replacement rate, macrowear, tooth wear rate, traditional microwear, and dental microwear texture analysis (DMTA). Tooth formation time is similar in Hungarosaurus and Mochlodon, and traditional and DMTA microwear features suggest low-browsing habits for both taxa, consistent with their inferred stances and body sizes. However, Mochlodon possesses a novel adaptation for increasing dental durability: the dentine on the working side of the crown is double the thickness of that on the balancing side. Moreover, crown morphology, enamel thickness, macrowear orientation, and wear rate differ greatly between the two taxa. Consequently, these sympatric herbivores probably exploited plants of different toughness, implying dietary selectivity and niche partitioning. Hungarosaurus is inferred to have eaten softer vegetation, whereas Mochlodon likely fed on tougher material. Compared to the much heavier, quadrupedal Hungarosaurus, the bipedal Mochlodon wore down more than twice as much of its crown volume during the functional life of the tooth. This heavy tooth wear might correlate with more intensive food processing and, in turn, could reflect differences in the metabolic requirements of these animals.
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Martin LF, Ackermans NL, Richter H, Kircher P, Hummel J, Codron D, Clauss M, Hatt J. Macrowear effects of external quartz abrasives of different size and concentration in rabbits (Oryctolagus cuniculus). JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2022; 338:586-597. [PMID: 34813148 PMCID: PMC9787991 DOI: 10.1002/jez.b.23104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 10/27/2021] [Accepted: 10/30/2021] [Indexed: 12/30/2022]
Abstract
External quartz abrasives are one of the driving forces of macrowear in herbivorous animals. We tested to what extent different sizes and concentrations influence their effect on tooth wear. We fed seven pelleted diets varying only in quartz concentration (0%, 4%, and 8%) and size (fine silt: ∼4 μm, coarse silt: ∼50 μm, fine sand: ∼130 μm) to rabbits (Oryctolagus cuniculus, n = 16) for 2 weeks each in a randomized serial experiment. Measurements to quantify wear and growth of incisors and the mandibular first cheek tooth, as well as heights of all other cheek teeth, were performed using calipers, endoscopic examination, and computed tomography scans before and after each feeding period. Tooth growth showed a compensatory correlation with wear. Absolute tooth height (ATH) and relative tooth height (RTH); relative to the 0% quartz "control" diet) was generally lower on the higher concentration and the larger size of abrasives. The effect was more pronounced on the maxillary teeth, on specific tooth positions and the right jaw side. When offered the choice between different sizes of abrasives, the rabbits favored the silt diets over the control and the fine sand diet; in a second choice experiment with different diets, they selected a pelleted diet with coarse-grained sand, however. This study confirms the dose- and size-dependent wear effects of external abrasives, and that hypselodont teeth show compensatory growth. The avoidance of wear did not seem a priority for animals with hypselodont teeth, since the rabbits did not avoid diets inducing a certain degree of wear.
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Affiliation(s)
- Louise F. Martin
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse FacultyUniversity of ZurichZurichSwitzerland
| | - Nicole L. Ackermans
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse FacultyUniversity of ZurichZurichSwitzerland,Present address:
Nicole L. Ackermans, Nash Family Department of Neuroscience, Friedman Brain Institute, Center for Anatomy and Functional MorphologyIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Henning Richter
- Clinic for Diagnostic Imaging, Vetsuisse FacultyUniversity of ZurichZurichSwitzerland
| | - Patrick Kircher
- Clinic for Diagnostic Imaging, Vetsuisse FacultyUniversity of ZurichZurichSwitzerland
| | - Jürgen Hummel
- Divison of Ruminant Nutrition, Department of Animal SciencesUniversity of GoettingenGoettingenGermany
| | - Daryl Codron
- Department of Zoology and EntomologyUniversity of the Free StateBloemfonteinSouth Africa
| | - Marcus Clauss
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse FacultyUniversity of ZurichZurichSwitzerland
| | - Jean‐Michel Hatt
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse FacultyUniversity of ZurichZurichSwitzerland
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7
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Winkler DE, Iijima M, Blob RW, Kubo T, Kubo MO. Controlled feeding experiments with juvenile alligators reveal microscopic dental wear texture patterns associated with hard-object feeding. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.957725] [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 wear analyses are classically applied to mammals because they have evolved heterodont dentitions for sophisticated mastication. Recently, several studies have shown a correlation between pre-assigned and analytically inferred diet preferences in extant reptiles through dental microwear texture analysis (DMTA), a method using quantitative assessment of microscopic wear marks to reconstruct the diet material properties. The first tentative applications of DMTA to extinct reptiles have followed. However, for large and small mammals, microwear analyses have undergone a long time of ground-truthing through direct feeding observations, stomach content analyses, and feeding experiments. Such data are currently lacking for reptiles, but are necessary to further extend DMTA, especially to Archosauria, as the application to dinosaurs could be of great interest to the scientific community. We herein present data from a pilot feeding experiment with five juvenile American alligators (Alligator mississippiensis). Each individual received a diet of assumed different hardness for ~4 months: crocodylian pellets (control), sardines, quails, rats, or crawfish. All individuals initially received the same pellet diet, and we found them to show similar dental microwear texture patterns before they were switched to their designated experimental diet. From the first feeding bout on, dental microwear textures differed across the diets. The crawfish-feeder showed consistently higher surface complexity, followed by the rat-feeder. Quail- and fish-feeding resulted in similar wear signatures, with low complexity. Fast tooth replacement and selective tooth use likely affected microwear formation, but we were able to detect a general hard (crawfish and rat) versus soft (quail and fish) DMTA signature. Such patterns can support the identification of hard-object feeding in the fossil record.
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Winkler DE, Clauss M, Kubo MO, Schulz-Kornas E, Kaiser TM, Tschudin A, De Cuyper A, Kubo T, Tütken T. Microwear textures associated with experimental near-natural diets suggest that seeds and hard insect body parts cause high enamel surface complexity in small mammals. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.957427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In mammals, complex dental microwear textures (DMT) representing differently sized and shaped enamel lesions overlaying each other have traditionally been associated with the seeds and kernels in frugivorous diets, as well as with sclerotized insect cuticles. Recently, this notion has been challenged by field observations as well as in vitro experimental data. It remains unclear to what extent each food item contributes to the complexity level and is reflected by the surface texture of the respective tooth position along the molar tooth row. To clarify the potential of seeds and other abrasive dietary items to cause complex microwear textures, we conducted a controlled feeding experiment with rats. Six individual rats each received either a vegetable mix, a fruit mix, a seed mix, whole crickets, whole black soldier fly larvae, or whole day-old-chicks. These diets were subjected to material testing to obtain mechanical properties, such as Young’s modulus, yield strength, and food hardness (as indicated by texture profile analysis [TPA] tests). Seeds and crickets caused the highest surface complexity. The fruit mix, seed mix, and crickets caused the deepest wear features. Moreover, several diets resulted in an increasing wear gradient from the first to the second molar, suggesting that increasing bite force along the tooth row affects dental wear in rats on these diets. Mechanical properties of the diets showed different correlations with DMT obtained for the first and second molars. The first molar wear was mostly correlated with maximum TPA hardness, while the second molar wear was strongly correlated with maximum yield stress, mean TPA hardness, and maximum TPA hardness. This indicates a complex relationship between chewing mechanics, food mechanical properties, and observed DMT. Our results show that, in rats, seeds are the main cause of complex microwear textures but that hard insect body parts can also cause high complexity. However, the similarity in parameter values of surface textures resulting from seed and cricket consumption did not allow differentiation between these two diets in our experimental approach.
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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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10
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Fannin LD, Laugier EJ, van Casteren A, Greenwood S, Dominy NJ. Differentiating siliceous particulate matter in the diets of mammalian herbivores. Methods Ecol Evol 2022. [DOI: 10.1111/2041-210x.13934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Luke D. Fannin
- Department of Anthropology Dartmouth College Hanover NH USA
- Graduate Program in Ecology, Evolution, Environment, and Society Dartmouth College Hanover NH USA
| | - Elise J. Laugier
- Department of Anthropology Dartmouth College Hanover NH USA
- Graduate Program in Ecology, Evolution, Environment, and Society Dartmouth College Hanover NH USA
| | - Adam van Casteren
- School of Biological Sciences University of Manchester Manchester UK
| | - Sabrina L. Greenwood
- Department of Animal and Veterinary Sciences University of Vermont Burlington VT USA
| | - Nathaniel J. Dominy
- Department of Anthropology Dartmouth College Hanover NH USA
- Department of Biological Sciences Dartmouth College Hanover NH USA
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11
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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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12
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Feeding ecology of the last European colobine monkey, Dolichopithecus ruscinensis. J Hum Evol 2022; 168:103199. [PMID: 35667203 DOI: 10.1016/j.jhevol.2022.103199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/30/2022] [Accepted: 03/30/2022] [Indexed: 11/23/2022]
Abstract
Currently, very little is known about the ecology of extinct Eurasian cercopithecids. Dietary information is crucial in understanding the ecological adaptations and diversity of extinct cercopithecids and the evolution of this family. For example, the colobine genus Dolichopithecus is represented by multiple large-bodied species that inhabited Eurasia during the Pliocene-Early Pleistocene. The available evidence, though limited, suggests semiterrestrial locomotion, which contrasts with most extant African and Asian colobines that exhibit morphological and physiological adaptations for arboreality and folivory. These differences raise questions regarding the dietary specialization of early colobine taxa and how/if that influenced their dispersion out of Africa and into Eurasia. To further our understanding of the ecology of Plio-Pleistocene cercopithecids, we characterized the dental capabilities and potential dietary adaptations of Dolichopithecus ruscinensis through dental topographic and enamel thickness analyses on an M1 from the locality of Serrat d'en Vacquer, Perpignan (France). We also assessed the feeding behavior of D. ruscinensis through dental microwear texture analysis on a broad sample of fossil molars from fossil sites in France, Greece, Bulgaria, and Romania. Dental topographic and enamel thickness analyses suggest that D. ruscinensis could efficiently process a wide range of foods. Results of the dental microwear texture analysis suggest that its diet ranged from folivory to the consumption of more mechanically challenging foods. Collectively, this suggests a more opportunistic feeding behavior for Dolichopithecus than characteristic of most extant colobines.
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Fischer VL, Winkler DE, Głogowski R, Attin T, Hatt JM, Clauss M, Wegehaupt F. Species-specific enamel differences in hardness and abrasion resistance between the permanent incisors of cattle (Bos primigenius taurus) and the ever-growing incisors of nutria (Myocastor coypus). PLoS One 2022; 17:e0265237. [PMID: 35298510 PMCID: PMC8929658 DOI: 10.1371/journal.pone.0265237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 02/25/2022] [Indexed: 11/30/2022] Open
Abstract
Hypselodont (ever-growing) teeth of lagomorphs or rodents have higher wear rates (of a magnitude of mm/week), with compensating growth rates, compared to the non-ever-growing teeth of ungulates (with a magnitude of mm/year). Whether this is due to a fundamental difference in enamel hardness has not been investigated so far. We prepared enamel samples (n = 120 per species) from incisors of cattle (Bos primigenius taurus) and nutria (Myocastor coypus, hypselodont incisors) taken at slaughterhouses, and submitted them to indentation hardness testing. Subsequently, samples were split into 4 groups per species (n = 24 per species and group) that were assessed for abrasion susceptibility by a standardized brush test with a control (no added abrasives) and three treatment groups (using fine silt at 4 ±1 μm particle size, volcanic ash at 96 ±9 μm, or fine sand at 166 ±15 μm as abrasives), in which enamel abrasion was quantified as height loss by before-and-after profilometry. The difference in enamel hardness between the species was highly significant, with nutria enamel achieving 78% of the hardness of cattle enamel. In the control and the fine sand group, no enamel height loss was evident, which was attributed to the in vitro system in the latter group, where the sand particles were brushed out of the test slurry by the brushes’ bristles. For fine silt and volcanic ash, nutria enamel significantly lost 3.65 and 3.52 times more height than cattle. These results suggest a relationship between enamel hardness and susceptibility to abrasion. However, neither the pattern within the species nor across the species indicated a monotonous relationship between hardness and height loss; rather, the difference was due to qualitative step related to species. Hence, additional factors not measured in this study must be responsible for the differences in the enamel’s susceptibility to abrasion. While the in vitro brush system cannot be used to rank abrasive test substances in terms of their abrasiveness, it can differentiate abrasion susceptibility in dental tissue of different animal species. The results caution against considering enamel wear as a similar process across mammals.
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Affiliation(s)
- Valentin L. Fischer
- Vetsuisse Faculty, Clinic for Zoo Animals, Exotic Pets and Wildlife, University of Zurich, Zurich, Switzerland
| | - Daniela E. Winkler
- Department of Natural Environmental Studies, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, Japan
- Institute of Geosciences, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Robert Głogowski
- Institute of Animal Science, Warsaw University of Life Sciences, Warsaw, Poland
| | - Thomas Attin
- Division of Preventive Dentistry and Oral Epidemiology, Centre of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Jean-Michel Hatt
- Vetsuisse Faculty, Clinic for Zoo Animals, Exotic Pets and Wildlife, University of Zurich, Zurich, Switzerland
| | - Marcus Clauss
- Vetsuisse Faculty, Clinic for Zoo Animals, Exotic Pets and Wildlife, University of Zurich, Zurich, Switzerland
- * E-mail:
| | - Florian Wegehaupt
- Division of Preventive Dentistry and Oral Epidemiology, Centre of Dental Medicine, University of Zurich, Zurich, Switzerland
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14
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Kropacheva YE, Zykov SV. An evaluation of individual seasonal changes in dental macro- and mesowear of wild-caught common vole (Microtus arvalis sensu lato) by the intravital impressions method. Mamm Biol 2022. [DOI: 10.1007/s42991-022-00252-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Fannin LD, Singels E, Esler KJ, Dominy NJ. Grit and consequence. Evol Anthropol 2021; 30:375-384. [PMID: 34652829 DOI: 10.1002/evan.21927] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 05/03/2021] [Accepted: 09/29/2021] [Indexed: 11/11/2022]
Abstract
Grit is implicated in several biological phenomena-it wears teeth, it fractures teeth, it drives tooth evolution, it elicits complex manual manipulations-any one of which could be described as a central topic in evolutionary anthropology. But what is grit? We hardly know because we tend to privilege the consequences of grit (it is abrasive) over its formal features, all but ignoring crucial variables such as mineral composition, material properties, and particle geometry (size, angularity), not to mention natural variation in the habitats of primates and their food surfaces. Few topics have animated so much debate and invited such cool indifference at the same time. Our goal here is to shine a light on grit, to put a philosophical lens on the nature of our discourse, and to call attention to large empirical voids that should be filled and folded into our understanding of primate natural history and evolution.
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Affiliation(s)
- Luke D Fannin
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA.,Graduate Program in Ecology, Evolution, Environment, and Society, Dartmouth College, Hanover, New Hampshire, USA
| | - Elzanne Singels
- Department of Conservation Ecology and Entomology, Stellenbosch University, Stellenbosch, South Africa
| | - Karen J Esler
- Department of Conservation Ecology and Entomology, Stellenbosch University, Stellenbosch, South Africa
| | - Nathaniel J Dominy
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA.,Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, USA
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16
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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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17
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Winkler DE, Clauss M, Rölle M, Schulz-Kornas E, Codron D, Kaiser TM, Tütken T. Dental microwear texture gradients in guinea pigs reveal that material properties of the diet affect chewing behaviour. J Exp Biol 2021; 224:269143. [PMID: 34124765 DOI: 10.1242/jeb.242446] [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] [Received: 02/16/2021] [Accepted: 06/08/2021] [Indexed: 11/20/2022]
Abstract
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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Affiliation(s)
- Daniela E Winkler
- Applied and Analytical Palaeontology, Institute of Geosciences, Johannes Gutenberg University, J.-J.-Becher-Weg 21, 55128 Mainz, Germany.,Department of Natural Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563, Japan.,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, 8057 Zurich, Switzerland
| | - Maximilian Rölle
- Applied and Analytical Palaeontology, Institute of Geosciences, Johannes Gutenberg University, J.-J.-Becher-Weg 21, 55128 Mainz, Germany
| | - Ellen Schulz-Kornas
- Center of Natural History, University of Hamburg, 20146 Hamburg, Germany.,Department of Cariology, Endodontology and Periodontology, University of Leipzig, 04103 Leipzig, Germany.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Daryl Codron
- Department of Zoology and Entomology, University of the Free State, Bloemfontein 9300, South Africa
| | - Thomas M Kaiser
- Center of Natural History, University of Hamburg, 20146 Hamburg, Germany
| | - Thomas Tütken
- Applied and Analytical Palaeontology, Institute of Geosciences, Johannes Gutenberg University, J.-J.-Becher-Weg 21, 55128 Mainz, Germany
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19
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Dental wear patterns reveal dietary ecology and season of death in a historical chimpanzee population. PLoS One 2021; 16:e0251309. [PMID: 33970963 PMCID: PMC8109778 DOI: 10.1371/journal.pone.0251309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/25/2021] [Indexed: 11/19/2022] Open
Abstract
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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Bethune E, Schulz-Kornas E, Lehnert K, Siebert U, Kaiser TM. Tooth Microwear Texture in the Eastern Atlantic Harbour Seals (Phoca vitulina vitulina) of the German Wadden Sea and Its Implications for Long Term Dietary and Ecosystem Changes. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.644019] [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
Marine mammals are increasingly threatened in their habitat by various anthropogenic impacts. This is particularly evident in prey abundance. Understanding the dietary strategies of marine mammal populations can help predict implications for their future health status and is essential for their conservation. In this study we provide a striking example of a new dietary proxy in pinnipeds to document marine mammal diets using a dental record. In this novel approach, we used a combination of 49 parameters to establish a dental microwear texture (DMTA) as a dietary proxy of feeding behaviour in harbour seals. This method is an established approach to assess diets in terrestrial mammals, but has not yet been applied to pinnipeds. Our aim was to establish a protocol, opening DMTA to pinnipeds by investigating inter- and intra-individual variations. We analysed the 244 upper teeth of 78 Atlantic harbour seals (Phoca vitulina vitulina). The specimens were collected in 1988 along the North Sea coast (Wadden Sea, Germany) and are curated by the Zoological Institute of Kiel University, Germany. An increasing surface texture roughness from frontal to distal teeth was found and related to different prey processing biomechanics. Ten and five year old individuals were similar in their texture roughness, whereas males and females were similar to each other with the exception of their frontal dentition. Fall and summer specimens also featured no difference in texture roughness. We established the second to fourth postcanine teeth as reference tooth positions, as those were unaffected by age, sex, season, or intra-individual variation. In summary, applying indirect dietary proxies, such as DMTA, will allow reconstructing dietary traits of pinnipeds using existing skeletal collection material. Combining DMTA with time series analyses is a very promising approach to track health status in pinniped populations over the last decades. This approach opens new research avenues and could help detect dietary shifts in marine environments in the past and the future.
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21
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Weber M, Tacail T, Lugli F, Clauss M, Weber K, Leichliter J, Winkler DE, Mertz-Kraus R, Tütken T. Strontium Uptake and Intra-Population 87Sr/86Sr Variability of Bones and Teeth—Controlled Feeding Experiments With Rodents (Rattus norvegicus, Cavia porcellus). Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.569940] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Strontium isotopes in biogenic apatite, especially enamel, are widely employed to determine provenance and track migration in palaeontology and archaeology. Body tissues record the 87Sr/86Sr of bioavailable Sr of ingested food and water. To identify non-local individuals, knowledge of the 87Sr/86Sr of a non-migratory population is required. However, varying factors such as tissue turnover rates, feeding selectivity, Sr content, digestibility of food, and the ingestion of mineral dust can influence body tissue 87Sr/86Sr. To evaluate the Sr contribution of diet and water to mammalian hard tissues 87Sr/86Sr, controlled feeding studies are necessary. Here we present 87Sr/86Sr from controlled feeding experiments with two rodent species (Rattus norvegicus, Cavia porcellus). Due to the continuous and fast incremental growth of rat and guinea pig incisors (~0.1 – 0.5 mm/day), their enamel is expected to record isotopic dietary changes. For Experiment-1: Diet Switch, animals were switched from their respective supplier food to a pelleted experimental diet containing either insect-, plant-, or meat-meal and a staggered-sampling approach was used to monitor the 87Sr/86Sr changes in rat incisor enamel and bone over the course of the experiment. In Experiment-2: Basic Diets, separated cohorts (n = 6) of rats and guinea pigs were fed one of the three pelleted diets and received tap water for 54 days. While the rat incisors showed a complete tissue turnover, the slower-growing guinea pig incisors partially retained supplier diet-related isotopic compositions. In addition, one group of rats fed plant-meal pellets received Sr-rich mineral water, demonstrating that drinking water can be an important Sr source in addition to diet. Additionally, a leaching experiment showed that only a small fraction of diet-related Sr is bioavailable. Finally, in Experiment-3: Dust Addition, guinea pigs were fed pellets with and without addition of 4% of isotopically distinct dust (loess or kaolin). Animals that received kaolin-containing pellets displayed increased enamel 87Sr/86Sr. Intra-population 87Sr/86Sr variability within each feeding group was small and thus we conclude that it should not affect interpretations of 87Sr/86Sr in provenance studies. However, the differences between bulk food and leachate 87Sr/86Sr highlight the importance of Sr bioavailability for provenance studies and Sr isoscapes.
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