3D meshed axiomatics of a microscope scan of the molar of a vervet monkey (Chlorocebus aethiops)
Dissertation Research
My research focused on variation in dental microwear textures as a method to reconstruct the dietary diversity of fossil monkeys. Dietary diversity is a measure of how varied diet is; high dietary diversity is linked to larger geographic ranges and greater species abundances, so understanding the dietary diversity of fossil species can help us better understand species's evolution. Dental microwear, the microscopic wear left on tooth enamel, captures information on what an animal ate in the last few weeks before it died. With a large enough sample, the variance in microwear within a species should approximate how diverse the diet of that species was. 
Summed weighted variances plotted against dietary diversity and frequency of fruit and foliage in the annual diet of seven species of Cercopithecidae. Pearson's product moment correlation (r) given.
I tested whether the intraspecific variance in six microwear variables, each capturing information about different aspects of the 3D topography of dental surfaces at different scales, could approximate the dietary diversity of each species. Using scans from 306 specimens of modern African Old World monkeys (Cercopithecidae) from eight species, I found that the summed weighted variances of the microwear variables could help predict how diverse a species's diet was. However, the summed variances were even better at predicting the frequency of fruit and leaves in the annual diet of each species. These methods can be used to examine the dietary diversity of fossil species, including hominins, our fossil relatives.
To read more about this research, please see Chapter 2 of my dissertation. To learn more about dental microwear texture methods, visit Peter Ungar's dental microwear website. Modeling Impala historic distribution Species distribution modeling (SDM), also known as niche or habitat modeling, uses the known distribution of a species in conjunction with environmental data to predict the geographic distribution of a species. I used Maxent, a specialized software developed for SDM, along with a paleoclimate model from WorldClim to predict impala (Aepyceros melampus) distribution at the Last Glacial Maximum (LGM; ~22,000 years ago). Two differences noted between the model and the fossil evidence include low predictions for presence in southern Ethiopia, north of Lake Turkana, although fossil Aepyceros have been recovered here, and high predicted presence across central Africa, where fossils are not found due to wet and forested modern conditions. For a full description of this model, please see my project white paper. For further information on SDM, I recommend Janet Franklin's Mapping Species Distributions. |
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Model of modern impala distribution using 2.5 arc minute resolution. White squares represent testing points.
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Projected model of impala distribution at the LGM; also shown (!) are fossil sites with records of impala.
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Publications
2016 Shapiro, A. E., Venkataraman, V. V., Fashing, P. J., Nguyen, N. Dietary ecology of fossil Theropithecus: inferences from dental
microwear textures of extant geladas from ecologically diverse sites. J Hum Evolution, 99: 1-9.
2015 Shapiro, A. E. Variation in dental microwear textures and dietary variation in African Old World monkeys (Cercopithecidae).
PhD Dissertation. Arizona State University: Tempe, AZ.
2015 Shapiro, A. E. Reconstructing dietary diversity in primates using variation in dental microwear textures.
Paleoanthropology Society (meeting poster).
2015 Shapiro, A. E. Using variation in dental microwear textures as a proxy for dietary diversity in Cercopithecidae.
Am J Phys Anthropol, 156 (S60): 285.
2014 Shapiro, A. E. Variation in dental microwear textures as a proxy for dietary breadth in Cercopithecidae.
Society of Vertebrate Paleontology (Meeting Poster).
2013 Shapiro, A. E., Venkataraman, V. V., Fashing, P. J., Nguyen, N. Dietary variability yields novel dental microwear textures for geladas.
Am J Phys Anthropol, 150 (S56): 251.
2012 Shapiro, A. E. Determining sources of dental microwear texture variation in anthropoids. Am J Phys
Anthropol, 147 (S52): 267.
2009 Shapiro, A. E. Differences in cercopithecid communities in the African Plio-Pleistocene. Am J Phys
Anthropol, 138 (S48): 235-236.
2016 Shapiro, A. E., Venkataraman, V. V., Fashing, P. J., Nguyen, N. Dietary ecology of fossil Theropithecus: inferences from dental
microwear textures of extant geladas from ecologically diverse sites. J Hum Evolution, 99: 1-9.
2015 Shapiro, A. E. Variation in dental microwear textures and dietary variation in African Old World monkeys (Cercopithecidae).
PhD Dissertation. Arizona State University: Tempe, AZ.
2015 Shapiro, A. E. Reconstructing dietary diversity in primates using variation in dental microwear textures.
Paleoanthropology Society (meeting poster).
2015 Shapiro, A. E. Using variation in dental microwear textures as a proxy for dietary diversity in Cercopithecidae.
Am J Phys Anthropol, 156 (S60): 285.
2014 Shapiro, A. E. Variation in dental microwear textures as a proxy for dietary breadth in Cercopithecidae.
Society of Vertebrate Paleontology (Meeting Poster).
2013 Shapiro, A. E., Venkataraman, V. V., Fashing, P. J., Nguyen, N. Dietary variability yields novel dental microwear textures for geladas.
Am J Phys Anthropol, 150 (S56): 251.
2012 Shapiro, A. E. Determining sources of dental microwear texture variation in anthropoids. Am J Phys
Anthropol, 147 (S52): 267.
2009 Shapiro, A. E. Differences in cercopithecid communities in the African Plio-Pleistocene. Am J Phys
Anthropol, 138 (S48): 235-236.