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During the late Pleistocene and early Holocene, Bison was widely dispersed across North America and occupied most regions not covered by ice sheets. A dietary study on Bison paleopopulations from Alaska, New Mexico, Florida, and Texas was performed using two methods that relate dental wear patterns to diet, mesowear analysis and microwear analysis. These data were compared to a mixed sample of extant Bison from the North American central plains, extant wood Bison from Alberta (Canada) and a variety of other modern ungulates. Mesowear relates macroscopic molar facet shape to levels of dietary abrasion. The mesowear signature observed on fossil Bison differs significantly from the hyper-abrasive grazing diet of extant Bison. Tooth microwear examines wear on the surface of enamel at a microscopic scale. The microwear signal of fossil samples resembles to modern Bison, but the fossil samples show a greater diversity of features, suggesting that fossil Bison populations regularly consumed food items that are texturally inconsistent with the short-grass diet typical of modern plains Bison. Mesowear and microwear signals of fossil Bison samples most closely resemble a variety of typical mixed feeding ungulates, all with diets that are substantially less abrasive than what is typical for modern plains Bison. Furthermore, statistical tests suggest significant differences between the microwear signatures of the fossil samples, thus revealing geographic variability in Pleistocene Bison diets. This study reveals that fossils are of value in developing an understanding of the dietary breadth and ecological versatility of species that, in recent times, are rare, endangered, and occupy only a small remnant of their former ranges. 相似文献
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J. Tyler Faith 《Quaternary Research》2011,75(1):159-165
The Cape grysbok is endemic to southern Africa's Cape Floral Region where it selectively browses various species of dicotyledonous vegetation. Fossil evidence indicates that the grysbok persisted under glacial and interglacial conditions throughout the late Quaternary and inhabited a range of environments. This study employs mesowear analysis to reconstruct grysbok diets over time and in response to changing environments at Nelson Bay Cave, Die Kelders Cave 1, Klasies River Mouth, and Swartklip 1. Results indicate that the amount of grasses (monocots) versus leafy vegetation (dicots) included in the diet fluctuated over time and largely in agreement with changes in faunal community structure. The case for dietary flexibility is particularly clear at Nelson Bay Cave, where there is a significant trend from mixed feeding towards increased browsing from the late Pleistocene (~ 18,500 14C yr BP) through the Holocene. Dietary shifts at Nelson Bay Cave are consistent with the hypothesis that declining grassland productivity is responsible for the terminal Pleistocene extinction of several large ungulates in southern Africa. Furthermore, the short-term dietary shifts demonstrated here (100s to 1000s of years) provide an important caution against relying on taxonomic uniformitarianism when reconstructing the dietary preferences of fossil ungulates, both extant and extinct. 相似文献
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Deano D. Stynder 《Quaternary Research》2009,71(1):62-70
The dietary regimes of 15 ungulate species from the middle Pleistocene levels of the hominid-bearing locality of Elandsfontein, South Africa, are investigated using the mesowear technique. Previous studies, using taxonomic analogy, classified twelve of the studied species as grazers (Redunca arundinum, Hippotragus gigas, Hippotragus leucophaeus, Antidorcas recki, Homoiceras antiquus, Damaliscus aff. lunatus, Connochaetes gnou laticornutus, Rabaticerus arambourgi, Damaliscus niro, Damaliscus sp. nov., an unnamed “spiral horn” antelope and Equus capensis), one as a mixed feeder (Taurotragus oryx) and two as browsers (Tragelaphus strepsiceros and Raphicerus melanotis). Although results from mesowear analysis sustain previous dietary classifications in the majority of cases, five species were reclassified. Three species previously classified as grazers, were reclassified as mixed feeders (H. gigas, D. aff. lunatus and R. arambourgi), one previously classified as a grazer, was reclassified as a browser (the “spiral horn” antelope), and one previously classified as a mixed feeder, was reclassified as a browser (T. oryx). While current results broadly support previous reconstructions of the Elandsfontein middle Pleistocene environment as one which included a substantial C3 grassy component, the reclassifications suggest that trees, broad-leaved bush and fynbos were probably more prominent than what was previously thought. 相似文献
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The dietary regime of Equus capensis from the Middle Pleistocene of South Africa is investigated by mesowear analysis. Results indicate that the mesowear signature of this species resembles that of two extant mixed feeders, the Grant's Gazelle (Gazella granti) and the Thomson's Gazelle (Gazella thomsoni), suggesting a mixed feeding dietary strategy for E. capensis. The mesowear signature of a contemporaneous population of Equus mosbachensis from Europe (Arago, France) is also determined for comparative purposes and has a typical grazing signature. In general, all extant species of Equus are believed to be almost exclusively grazers. However, a considerable degree of dietary flexibility is recently reported. The dietary signal of E. capensis is considered to be the result of feeding on the unique fynbos vegetation, which was beginning to establish itself at this time in southwestern South Africa. Grasses are a minor component of this floral kingdom. Our findings thus provide further evidence for the unexpected flexibility in feeding strategies of Equus, the most widely distributed equid taxon in the Quaternary. They highlight the potential use of the attrition–abrasion wear equilibrium as a habitat indicator, by mirroring the availability of food items in mammalian herbivore ecosystems. 相似文献
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