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1.
The analysis of dental microwear is commonly used by paleontologists and anthropologists to clarify the diets of extinct species, including herbivorous and carnivorous mammals. Currently, there are numerous methods employed to quantify dental microwear, varying in the types of microscopes used, magnifications, and the characterization of wear in both two dimensions and three dimensions. Results from dental microwear studies utilizing different methods are not directly comparable and human quantification of wear features (e.g., pits and scratches) introduces interobserver error, with higher error being produced by less experienced individuals. Dental microwear texture analysis (DMTA), which analyzes microwear features in three dimensions, alleviates some of the problems surrounding two-dimensional microwear methods by reducing observer bias. Here, we assess the accuracy and comparability within and between 2D and 3D dental microwear analyses in herbivorous and carnivorous mammals at the same magnification. Specifically, we compare observer-generated 2D microwear data from photosimulations of the identical scanned areas of DMTA in extant African bovids and carnivorans using a scanning white light confocal microscope at 100x magnification. Using this magnification, dental microwear features quantified in 2D were able to separate grazing and frugivorous bovids using scratch frequency; however, DMTA variables were better able to discriminate between disparate dietary niches in both carnivorous and herbivorous mammals. Further, results demonstrate significant interobserver differences in 2D microwear data, with the microwear index remaining the least variable between experienced observers, consistent with prior research. Overall, our results highlight the importance of reducing observer error and analyzing dental microwear in three dimensions in order to consistently interpret diets accurately.  相似文献   

2.
龚宴欣 《古生物学报》2017,56(1):117-128
通过研究古哺乳动物的食性来探讨哺乳动物演化与古生态环境变化之间的关系是目前古生物学研究领域的一个热点,而牙齿磨痕分析是恢复古食性和重建古生态环境的重要手段。牙齿磨痕(dental wear)分析包括微痕(microwear)分析和中痕(mesowear)分析,两种方法均强调食性与牙齿磨痕模式的严格对应,即不同食性的动物具有不同的牙齿磨痕特征模式。近年来,牙齿磨痕分析方法以其简单、快捷和高效等优点已被广泛应用于奇蹄类、偶蹄类、啮齿类、长鼻类和食肉类等哺乳动物的食性研究。但哺乳动物的食性和摄食习性比较复杂,很可能会影响微痕和中痕分析对食性的分辨率。所以,为了获得更加详细的古食性信息和更高的食性分辨率,一方面要对微痕和中痕分析方法进行改进,增添稳定并具有食性识别意义的观测变量,另一方面,需要同时结合微痕和中痕分析,从而获得更加全面的食性信息。虽然牙齿磨痕分析目前主要应用于植食性哺乳动物的食性研究,但其原理对哺乳动物的其它类群也是适用的,随着磨痕分析方法的不断改进和其它类群磨痕数据库的建立,未来的牙齿磨痕分析将可以恢复更多类群的古食性,从而可以更加全面和准确地揭示古食性与古环境信息。  相似文献   

3.
The relationship between environmental change and hominin evolution remains obscure. For the most part, this stems from the difficulty of reconstructing ancient hominin habitats. Bovids are among the most frequently utilized paleoenvironmental indicators, but little is known about the habitat preferences of extinct taxa. It is generally assumed that fossil bovids both ate the same things and occupied the same habitats as their closest extant relatives. We test the first part of this assumption by reconstructing the diets of seven bovids from Makapansgat Limeworks, South Africa. Since diet and habitat are linked, these reconstructions have implications for our understanding of fossil bovid habitat tolerances. Ecomorphological and stable carbon isotope analyses are employed, allowing us to take advantage of the strengths and overcome the weaknesses of both. In most cases, fossil bovids did have similar diets to their extant relatives, and probably occupied similar habitats. Gazella vanhoepeni and Aepyceros sp., however, were almost exclusive browsers, and not mixed feeders like their living counterparts.  相似文献   

4.
Abstract

The study of dental wear was first used years ago to infer the palaeoecology of fossil mammals and in particular their diet. Results depend predominantly on the scale of the analysis used. Analyses of dental macrowear, mesowear or microwear do not provide the same type of dietary information, be it about the seasonal, annual or lifetime diet. This contribution focuses on emblematic species, cave bears (Ursidae), in particular Ursus spelaeus spelaeus. Methods used by previous researchers to infer their dietary preferences and thus their palaeoecology are reviewed and compared. This review is complemented by an analysis of several specimens of cave bears from the Goyet cave in Belgium, using dental microwear texture analysis (DMTA), a methodology widely applied for reconstructing palaeodiets. Three main conclusions are drawn here: (1) DMTA is the method that provides the most precise palaeobiological inferences; (2) during the pre-dormancy period, cave bears show dietary flexibility; (3) dental wear alone might be not sufficient to provide a complete reconstruction of the cave bear palaeodiet.  相似文献   

5.
Tooth microwear was analyzed for a large sample of wild-shot barren-ground caribou (Rangifer tarandus groenlandicus) from the Kaminuriak population of eastern Canada. This sample was compared to the microwear of specimens from three Pleistocene localities in North America (Alaska) and western Europe (Caune de l’Arago in France and Salzgitter in Germany). The results show that the extant samples from eastern Canada have seasonal variation in microwear and presumably in diet. The differences in microwear between the various seasons may reflect a cyclic migration of the population within a year. The extinct population from Alaska has extremely blunt teeth (mesowear), as blunt as those of modern zebras and bison. This observation is corroborated by the lowest number of microwear pits. The findings are untypical, as most typical caribou teeth have sharper apices, and we interpret this as an indication of a local habitat that was different with animals feeding on non-typical vegetation. The combination of Rangifer from Caune de l’Arago and Salzgitter reveals a pattern in microwear variability. The Salzgitter is interglacial and shows a greater diversity of browsing (broad spectrum on average number of pits) than the glacial Caune de l’Arago. The interglacial population from Salzgitter is interesting because it shows several different types of browsing. Collectively all the Rangifer teeth show that diet of a brachydont taxon can vary across most of the dietary morphospace of ungulates as represented by tooth microwear. The three Pleistocene samples exhibit microwear that is different from the extant population in question. This observation implies that the recent diet of Rangifer has changed from the typical caribou diet in the past. This indicates dietary change within a species. This is important because it represents dietary evolution without changes in tooth morphology.  相似文献   

6.
A variety of tooth‐wear and morphological dietary proxies have been proposed for ungulates. In turn, they have been applied to fossil specimens with the purpose of reconstructing the diets of extinct taxa. Although these dietary proxies have been used in isolation and in combination, a consistent set of statistical analyses has never been applied to all of the available datasets. The purpose of this study is to determine how well the most commonly used dietary proxies classify ungulates as browsers, grazers, and mixed feeders individually and in combination. Discriminant function analysis is applied to individual dietary proxies (hypsodonty, mesowear, microwear, and several cranial dietary proxies) and to combinations thereof to compare rates of successful dietary classification. In general, the tooth‐wear dietary proxies (mesowear and microwear) perform better than morphological dietary proxies, though none are strong proxies in isolation. The success rates of the cranial dietary proxies are not increased substantially when ruminants and bovids are analyzed separately, and significance among the three dietary guilds is reduced when controlling for phylogenetic relatedness. The combination of hypsodonty, mesowear, and microwear is found to have a high rate of successful dietary classification, but a combination of all commonly used proxies increases the success rate to 100%. In most cases, mixed feeders bear the greatest resemblance to browsers suggesting that a morphology intermediate to browsers and grazers may represent a fitness valley resulting from the inability to exploit both browse and graze efficiently. These results are important for future paleoecological studies and should be used as a guide for determining which dietary proxies are appropriate to the research question. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.  相似文献   

7.
The extensive early Pliocene mammalian assemblages at Langebaanweg hold the potential to provide important information about paleoenvironments of the southwestern tip of Africa, an area that today consititutes the Fynbos Biome. We here add to a growing body of literature on the paleoenviornments of the site with an examination of dental microwear textures of bovids from the Varswater Formation. Microwear texture analysis is a new, automated and repeatable approach that measures whole surfaces in three dimensions without observer error. A study of extant ruminants indicates that grazers have more anisotropic microwear surface textures, whereas browsers have more complex microwear surface textures. Fossil bovids recovered from the Muishond Fontein Pelletal Phosphorite Member vary in their microwear textures, with some taxa falling within the extant browser range, some closer to extant grazers, and others in between. These results are consistent with scenarios suggesting mosaic habitats including fynbos vegetation, some (probably C3) grasses, and woodland elements when these fossils were accumulated.  相似文献   

8.
Food consumption causes distinct microwear patterns on teeth, especially in mammals that actively masticate food. Here we perform a microwear analysis to assess the relationships between diet and microwear features of diverse Carnivora. Our database includes approximately 230 individuals of 17 extant species having different diets. We analyse both slicing and grinding facets of M1 and m1. The proposed method is reproducible and allows the differentiation, especially on slicing facets, of microwear poles that are significantly distinct from one another. In carnivorans, the microwear features mainly result from their foraging behavior and the proportion of certain food items consumed. We applied our method to extinct taxa such as the amphicyonid Amphicyon major. The results on the m1 slicing facet indicate dietary similarities between this large Miocene predator and the extant red fox; results from the m1 grinding facet do not have equivalent in extant taxa, however.  相似文献   

9.
Dental microwear and 3D surface texture analyses are useful in reconstructing herbivore diets, with scratches usually interpreted as indicators of grass dominated diets and pits as indicators of browse. We conducted feeding experiments with four groups of rabbits (Oryctolagus cuniculus) each fed a different uniform, pelleted diet (lucerne, lucerne & oats, grass & oats, grass). The lowest silica content was measured in the lucerne and the highest in the grass diet. After 25 weeks of exposure to the diets, dental castings were made of the rabbit''s lower molars. Occlusal surfaces were then investigated using dental microwear and 3D areal surface texture analysis. In terms of traditional microwear, we found our hypothesis supported, as the grass group showed a high proportion of (long) “scratches” and the lucerne group a high proportion of “pits”. Regardless of the uniform diets, variability of microwear and surface textures was higher when silica content was low. A high variability in microwear and texture analysis thus need not represent dietary diversity, but can also be related to a uniform, low-abrasion diet. The uniformity or variability of microwear/texture analysis results thus might represent varying degrees of abrasion and attrition rather than a variety of diet items per se.  相似文献   

10.
The South African Plio-Pleistocene cave deposits have yielded a diverse cercopithecoid fauna. In this study, the possible dietary proclivities of these extinct species are examined using details of molar microwear. Although sample sizes are often small, wear patterns suggest possible temporal changes in the diets of Parapapio jonesi from Makapansgat to Sterkfontein, of Papio robinsoni from Sterkfontein to Swartkrans, and Cercopithecoides williamsi from Makapansgat to Sterkfontein to Swartkrans. However, there does not appear to have been a significant change in the dietary habits of Parapapio broomi over time. The microwear patterns of the two temporally successive congeners, Theropithecus darti and T. oswaldi show no significant differences from one another. The sympatric congeners, Parapapio broomi and Pp. jonesi, have microwear signatures that differ significantly at Makapansgat (Members 3 and 4) but not at Sterkfontein (Member 4). Finally, the microwear analyses suggest that the extinct cercopithecoid species did not necessarily have diets similar to those of their closest living relatives.  相似文献   

11.
The Anchitheriinae are an extinct subfamily of Equidae that first appeared in North America near the base of the Miocene. Anchitheriinae are found in subtropical to warm temperate habitats and were long considered to be adapted to eating browse. In Europe the genus Anchitherium first occurred in the MN3 mammal zone and became extinct in MN9. The assemblage from Sandelzhausen (Early/Middle Miocene, boundary MN5) is one of the best dental samples known of Old World Anchitherium. The mesowear method was applied to reconstruct the dietary regime of A. aurelianense from Sandelzhausen. Hierarchical cluster statistics and principal component analysis was performed on mesowear variables. Thirty-five upper cheek teeth of A. aurelianense were analysed, and mesowear signatures compared with those of five ruminant species from Sandelzhausen. The extant analogue species indicate that A. aurelianense at Sandelzhausen had a diet similar in abrasiveness to that of extant mixed feeders and that the Sandelzhausen ruminants all occupied a browsing niche with little or no abrasives in their diet. Knowing now that brachydont anchitheres were able to cope with rather abrasive diets, it is assumed that hypsodont North American equids of the Cormohipparion clade, arriving in Europe successively with the extinction of anchitheres shortly after the “hipparion datum” in the MN9, introduced a new component of competition in their dietary niche. The extinction of the Anchitheriidae can now be better understood as response to this competition.   相似文献   

12.
《Palaeoworld》2021,30(4):724-736
Both the evolution of tooth morphology and the relationship between dental features and diet in toothed birds have long been studied. Here we quantify variation in tooth crown shape in 28 key Mesozoic bird species, and examine differences in dental morphology among birds belonging to different taxonomic groupings and inferred to have had different diets. Using geometric morphometric methods (GMM) and phylogenetic comparative methods (PCM), we found few clear differences in tooth crown shape between different taxonomic and ecological categories, and our analysis provides little support for many dietary inferences drawn in previous studies. However, the Solnhofen Archaeopteryx, Jeholornis, Protopteryx, Pengornis, Longipteryx, Tianyuornis, Mengciusornis, Ichthyornis and Hesperornis all were found to possess relatively specialized tooth crown shapes, perhaps reflecting specialized diets such as insectivory, granivory, piscivory and consumption of soft-shelled arthropods. Similarity in tooth crown shape across many Mesozoic birds may indicate the lack of dietary specialization, and the association between tooth form and diet may have been weakened in any case by ‘functional replacement’ of the dentition by a horny beak and, in many cases, gastroliths.  相似文献   

13.
The dietary morphological methods of mesowear and microwear were applied to ungulates of the late Pliocene fauna of Sésklo (Thessaly, Greece). The results provide evidence for the predominance of open grassland in the area, as the most common species, Equus stenonis, was a strict grazer. The rare cervid cf. Croizetoceros ramosus was the only browser. The antelopes (genera Gazella and Gazellospira) yielded discrepant microwear and mesowear results. This is interpreted as an indication of regional or seasonal dietary resource differentiation, inferring that the antelopes were probably mixed feeders that grazed occasionally or periodically.  相似文献   

14.
Many researchers have suggested that Australopithecus anamensis and Australopithecus afarensis were among the earliest hominins to have diets that included hard, brittle items. Here we examine dental microwear textures of these hominins for evidence of this. The molars of three Au. anamensis and 19 Au. afarensis specimens examined preserve unobscured antemortem microwear. Microwear textures of these individuals closely resemble those of Paranthropus boisei, having lower complexity values than Australopithecus africanus and especially Paranthropus robustus. The microwear texture complexity values for Au. anamensis and Au. afarensis are similar to those of the grass-eating Theropithecus gelada and folivorous Alouatta palliata and Trachypithecus cristatus. This implies that these Au. anamensis and Au. afarensis individuals did not have diets dominated by hard, brittle foods shortly before their deaths. On the other hand, microwear texture anisotropy values for these taxa are lower on average than those of Theropithecus, Alouatta or Trachypithecus. This suggests that the fossil taxa did not have diets dominated by tough foods either, or if they did that directions of tooth–tooth movement were less constrained than in higher cusped and sharper crested extant primate grass eaters and folivores.  相似文献   

15.
Extant rhinos are the largest extant herbivores exhibiting dietary specialisations for both browse and grass. However, the adaptive value of the wear-induced tooth morphology in rhinos has not been widely studied, and data on individual cusp and tooth positions have rarely been published. We evaluated upper cheek dentition of browsing Diceros bicornis and Rhinoceros sondaicus, mixed-feeding R. unicornis and grazing Ceratotherium simum using an extended mesowear method adapted for rhinos. We included single cusp scoring (EM(R)-S) to investigate inter-cusp and inter-tooth wear patterns. In accordance with previous reports, general mesowear patterns in D. bicornis and R. sondaicus were attrition-dominated and C. simum abrasion-dominated, reflecting their respective diets. Mesowear patterns for R. unicornis were more attrition-dominated than anticipated by the grass-dominated diet, which may indicate a low intake of environmental abrasives. EM(R)-S increased differentiation power compared to classical mesowear, with significant inter-cusp and inter-tooth differences detected. In D. bicornis, the anterior cusp was consistently more abrasion-dominated than the posterior. Wear differences in cusp position may relate to morphological adaptations to dietary regimes. Heterogeneous occlusal surfaces may facilitate the comminution of heterogeneous browse, whereas uniform, broad grinding surfaces may enhance the comminution of physically more homogeneous grass. A negative tooth wear gradient was found in D. bicornis, R. sondaicus and R. unicornis, with wear patterns becoming less abrasion-dominated from premolars to molars. No such gradients were evident in C. simum which displayed a uniform wear pattern. In browsers, premolars may be exposed to higher relative grit loads, which may result in the development of wear gradients. The second premolar may also have a role in food cropping. In grazers, high absolute amounts of ingested abrasives may override other signals, leading to a uniform wear pattern and dental function along the tooth row, which could relate to the observed evolution towards homodonty.  相似文献   

16.
The early Miocene catarrhine fossil record of East Africa represents a diverse and extensive adaptive radiation. It is well accepted that these taxa encompass a dietary range similar to extant hominoids, in addition to some potentially novel dietary behaviour. There have been numerous attempts to infer diet for these taxa from patterns of dental allometry and incisor and molar microwear, however, morphometric analyses until now have been restricted to the post-canine dentition. It has already been demonstrated that given the key functional role of the incisors in pre-processing food items prior to mastication, there is a positive correlation between diet and incisal curvature (Deane, A.S., Kremer, E.P., Begun, D.R., 2005. A new approach to quantifying anatomical curvatures using High Resolution Polynomial Curve Fitting (HR-PCF). Am. J. Phys. Anthropol. 128(3), 630-638.; Deane, A.S., 2007. Inferring dietary behaviour for Miocene hominoids: A high-resolution morphometric approach to incisal crown curvature. Ph.D. Dissertation. The University of Toronto.). This study seeks to re-examine existing dietary hypotheses for large-bodied early Miocene fossil catarrhines by contrasting the incisal curvature for these taxa with comparative models derived from prior studies of the correlation between extant hominoid incisor curvature and feeding behaviour. Incisor curvature was quantified for 78 fossil incisors representing seven genera, and the results confirm that early Miocene fossil catarrhines represent a dietary continuum ranging from more folivorous (i.e., Rangwapithecus) to more frugivorous (i.e., Proconsul) diets, as well as novel dietary behaviours that are potentially similar to extant ceboids (i.e., Afropithecus). Additionally, early Miocene fossil catarrhine incisors are less curved than extant hominoid incisors, indicating a general pattern of increasing mesio-distal and labial curvature through time. This pattern of morphological shifting is consistent with the Red Queen Effect (Van Valen, L., 1973. A new evolutionary law. Evol. Theory 1, 1-30), which predicts that taxa that are removed from one another by geological time, although potentially having similar diets, may exhibit differing degrees of a similar dietary adaptation (i.e., differing degrees of incisal curvature).  相似文献   

17.
Dental microwear has long been used as evidence concerning the diets of extinct species. Here, we present a comparative baseline series of dental microwear textures for a sample of 21 anthropoid primate species displaying interspecific and intraspecific dietary variability. Four dental microwear texture variables (complexity, anisotropy, textural fill volume, and heterogeneity) were computed based on scale-sensitive fractal analysis and high-resolution three-dimensional renderings of microwear surfaces collected using a white-light confocal profiler. The purpose of this analysis was to assess the extent to which these variables reflect variation in diet. Significant contrasts between species with diets known to include foods with differing material properties are clearly evident for all four microwear texture variables. In particular, species that consume more tough foods, such as leaves, tended to have high levels of anisotropy and low texture complexity. The converse was true for species including hard and brittle items in their diets either as staples or as fallback foods. These results reaffirm the utility of dental microwear texture analysis as an important tool in making dietary inferences based on fossil primate samples.  相似文献   

18.
Buccal microwear patterns on teeth are good indicators of the abrasiveness of foodstuffs and have been used to trace the dietary habits of fossil species, including primates and hominids. However, few studies have addressed the variability of this microwear. The abrasiveness of dietary components depends not only on the hardness of the particles ingested, but also on the presence of dust and other exogenous elements introduced during food processing. These elements are responsible for the microwear typology observed on the enamel surfaces of primate teeth. Here we analyzed the variability of buccal microwear patterns in African Great Apes (Gorilla gorilla and Pan troglodytes), using tooth molds obtained from the original specimens held in several osteological collections. Our results suggest that ecological adaptations at subspecies or population level account for differences in microwear patterns, which are attributed to habitat and ecological conditions within populations rather than differences between species. The findings from studies on the variability of buccal dental microwear in extant species will contribute to a better understanding of extinct hominids’ diet and ecology.  相似文献   

19.
Here we compare dental microwear textures from specimens of the fossil genus Mesopithecus (Cercopithecidae, Colobinae) from the late Miocene of Eastern Europe with dental microwear textures from four extant primate species with known dietary differences. Results indicate that the dental microwear textures of Mesopithecus differ from those of extant leaf eaters Alouatta palliata and Trachypithecus cristatus and instead resemble more closely those of the occasional hard-object feeders Cebus apella and Lophocebus albigena. Microwear texture data presented here in combination with results from previous analyses suggest that Mesopithecus was a widespread, opportunistic feeder that often consumed hard seeds. These data are consistent with the hypothesis that early colobines may have preferred hard seeds to leaves.  相似文献   

20.
This low magnification stereomicrowear study samples a broad range of chalicotheres (Perissodactyla, Chalicotherioidea), including basal chalicotheres and the two chalicotheriid subfamilies Schizotheriinae and Chalicotheriinae, primarily including species from North America and Europe, but also some from Asia. The schizotheriines Moropus, Tylocephalonyx, and Metaschizotherium and the chalicotheriines Anisodon and Chalicotherium are best represented. Paleodiets are interpreted via discriminant analysis, using comparison of microwear variables from fossil chalicothere teeth with those from a database of extant ungulates with known diets. The results suggest that all of the chalicotheres in the study were browsers, with no evidence of significant grass consumption. Basal chalicotheres, like basal equids, seem to have been standard fruit-dominated browsers. Stereomicrowear agrees with mesowear results by Schulz et al. (2007) and Schulz and Fahlke (2009) for Metaschizotherium bavaricum, Metaschizotherium fraasi, Anisodon grande, and Chalicotherium goldfussi in showing a highly abrasive aspect to the diet. In these species, hard food objects such as fibrous fruits, seeds, pits, and nuts may have abraded the teeth (based on high pit counts, the presence of large puncture pits, and many individuals with coarse to hypercoarse scratches). Anisodon grande and C. goldfussi, despite their relatively short, brachydont teeth, show the highest degree of abrasion within the studied sample. Moropus and Tylocephalonyx from North America show somewhat different but also abrasive microwear; in these taxa the resistant foods may have been twigs and bark (large pits common, but gouging more prevalent than puncture pits). A preliminary comparison of stereomicrowear on DP4, the deciduous upper fourth premolar, with that on molars suggests that juveniles consumed similar foods as adults but without the most abrasive elements. Some important methodological differences regarding the scoring of microwear features by different low-magnification microwear methodologies are discussed.  相似文献   

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