Elicia F Abella | University of Arkansas (original) (raw)
Uploads
Poster Presentations by Elicia F Abella
Previous study has suggested that Australopithecus africanus and Paranthropus robustus have overl... more Previous study has suggested that Australopithecus africanus and Paranthropus robustus have overlapping molar microwear textures, but that A. africanus had a greater spread of anisotropy values, whereas P. robustus had more variable but a higher average complexity. This was taken to suggest overlapping diets, but more tough-food consumption by A. africanus and more hard-object feeding by P. robustus. The basis of that original work was a comparatively small sample, including only ten A. africanus specimens. Here we present data for an expanded sample, including both Sts and Stw specimens (n = 25 individuals) from Sterkfontein Member 4 with specimens from the previous study, to assess within-species variation in A. africanus. We considered only molar teeth, and examined them using standard confocal profilometry and scale-sensitive fractal analyses. Our results for both microwear texture complexity and anisotropy are consistent with the previous study based on the smaller sample. While the new data slightly extend the range of values for anisotropy and complexity, the expanded sample of A. africanus still overlaps with that for P. robustus, but has a higher average anisotropy and lower average complexity. This suggests, again, that compared with P. robustus, A. africanus individuals at Sterkfontein consumed more tough foods, and fewer hard, brittle ones in Member 4 times.
The Laetoli paleoanthropological site in northern Tanzania continues to yield one of the ol... more The Laetoli paleoanthropological site in northern Tanzania continues to yield one of the oldest Australopithecus afarensis collections as well as other well preserved non-hominin primate remains, including primate cercopithecids. The Laetoli primates are highly diversified, including fossil galagines, parapithecids and paracolobines. These primate species are indicative of highly variable depositional environments at Laetoli that would have been more wooded or forested with patches of bushes, thorn scrubs and open habitats. This research presents qualitative descriptions and a comparative computational statistical analysis (PCA and DFA) of odontometrics for the posterior teeth of fossil and extant primates as a way to securely classify recently recovered Laetoli fossil primate remains by the University of Colorado Denver Tanzania field school in paleoanthropology. The statistical analyses show that the posterior teeth can be used to distinguish speciation since tooth size can be indicative of dietary adaptations and habitat preferences. For instance, the PCA yields information on general groupings based on habitat preferences, whereas the DFA shows that the buccal teeth have a higher discriminatory power than the premolars; however M3 has the highest discriminatory ability in deciphering primate species and exhibits the lowest misclassification percentage (15.88%) for all tooth types although it is known that it possess the highest variability in tooth size and shape. The results of this analysis and classification of unknown primate species provides a better understanding of the ecological diversity exploited at Laetoli during the Pliocene and contributes to our understanding of primate diversity and dietary behaviors at Laetoli.
Unlike many other PlioPleistocene paleoanthropological sites in East Africa, the depositional and... more Unlike many other PlioPleistocene paleoanthropological sites in East Africa, the depositional and taphonomic history of vertebrate fossil faunal remains at Laetoli differs significantly in that it is time-averaged with low to moderate energy depositional events. The skeletal representation in the Laetoli bovids’ faunal remains is characterized by a high number of limb elements, especially astragali and calcanei that can be used not only in reconstructing depositional and taphonomic histories but also their locomotor and habitat preferences which provide proxy data for hominin paleoecology at Laetoli during the Upper Laetoli depositional events. We here present some taphonomic, depositional history and paleoecological construction of bovid habitat preferences in relation to hominin distribution and habitat utilization at select localities at Laetoli. Furthermore we use taphonomic and depositional history of the mammalian faunal assemblage at Laetoli to demonstrate how different Pliocene Laetoli was from other comparable sites in East Africa. Bovid astragali and calcanei in this study are used as ecomorphological indicators to piece together habitats that may have been utilized by hominins within the Upper Laetolil Beds depositional events.
Master's Thesis by Elicia F Abella
Papers by Elicia F Abella
Journal of human evolution, Jan 9, 2017
Reconstructions of habitat at sites like Kanapoi are key to understanding the environmental circu... more Reconstructions of habitat at sites like Kanapoi are key to understanding the environmental circumstances in which hominins evolved during the early Pliocene. While Australopithecus anamensis shows evidence of terrestrial bipedality traditionally associated with a more open setting, its enamel has low δ(13)C values consistent with consumption of C3 foods, which predominate in wooded areas of tropical Africa. Habitat proxies, ranging from paleosols and their carbonates to associated herbivore fauna and their carbon isotope ratios, suggest a heterogeneous setting with both grass and woody plant components, though the proportions of each have been difficult to pin down. Here we bring dental microwear texture analysis of herbivorous fauna to bear on the issue. We present texture data for fossil bovids, primates, rodents, and suids (n = 107 individuals in total) from the hominin bearing deposits at Kanapoi, and interpret these in the light of closely related extant mammals with known dif...
The Laetoli paleoanthropological site in northern Tanzania continues to yield one of the oldest A... more The Laetoli paleoanthropological site in northern Tanzania continues to yield one of the oldest Australopithecus afarensis collections as well as other well preserved non-hominin primate remains, including primate cercopithecids. The Laetoli primates are highly diversified, including fossil galagines, parapithecids and paracolobines. These primate species are indicative of highly variable depositional environments at Laetoli that would have been more wooded or forested with patches of bushes, thorn scrubs and open habitats. This research presents qualitative descriptions and a comparative computational statistical analysis (PCA and DFA) of odontometrics for the posterior teeth of fossil and extant primates as a way to securely classify recently recovered Laetoli fossil primate remains by the University of Colorado Denver Tanzania field school in paleoanthropology. The statistical analyses show that the posterior teeth can be used to distinguish speciation since tooth size can be indicative of dietary adaptations and habitat preferences. For instance, the PCA yields information on general groupings based on habitat preferences, whereas the DFA shows that the buccal teeth have a higher discriminatory power than the premolars; however M3 has the highest discriminatory ability in deciphering primate species and exhibits the lowest misclassification percentage (15.88%) for all tooth types although it is known that it possess the highest variability in tooth size and shape. The results of this analysis and classification of unknown primate species provides a better understanding of the ecological diversity exploited at Laetoli during the Pliocene and contributes to our understanding of primate diversity and dietary behaviors at Laetoli.
Journal of human evolution, 2018
The importance of diet in primate ecology has motivated the use of a variety of methods to recons... more The importance of diet in primate ecology has motivated the use of a variety of methods to reconstruct dietary habits of extinct hominin taxa. Dental microwear is one such approach that preserves evidence from consumed food items. This study is based on 44 specimens of Australopithecus africanus from Makapansgat and Sterkfontein, and 66 specimens of Paranthropus robustus from Swartkrans, Kromdraai and Drimolen. These samples enable examination of potential differences between the two assemblages of A. africanus, and among the various assemblages of P. robustus in relation to the paleoenvironmental reconstructions that have been proffered for each fossil site. Sixteen microwear texture variables were recorded for each specimen from digital elevation models generated using a white-light confocal profiler. Only two of these differ significantly between the Makapansgat and Sterkfontein samples of A. africanus. None of the microwear texture variables differs significantly among the sampl...
Journal of Human Evolution, 2018
The importance of diet in primate ecology has motivated the use of a variety of methods to recons... more The importance of diet in primate ecology has motivated the use of a variety of methods to reconstruct dietary habits of extinct hominin taxa. Dental microwear is one such approach that preserves evidence from consumed food items. This study is based on 44 specimens of Australopithecus africanus from Makapansgat and Sterkfontein, and 66 specimens of Paranthropus robustus from Swartkrans, Kromdraai and Drimolen. These samples enable examination of potential differences between the two assemblages of A. africanus, and among the various assemblages of P. robustus in relation to the paleoenvironmental reconstructions that have been proffered for each fossil site. Sixteen microwear texture variables were recorded for each specimen from digital elevation models generated using a white-light confocal profiler. Only two of these differ significantly between the Makapansgat and Sterkfontein samples of A. africanus. None of the microwear texture variables differs significantly among the samples of P. robustus. On the other hand, P. robustus has significantly higher values than A. africanus for 11 variables related to feature complexity, size, and depth; P. robustus exhibits rougher surfaces that comprise larger, deeper features. In contrast, A. africanus has smoother, simpler wear surfaces with smaller, shallower and more anisotropic features. As for possible habitat differences among the various sites, only a relatively small number of subtle differences are evident between the specimens of A. africanus from Makapansgat and Sterkfontein, and there are none among the specimens of P. robustus from various deposits. As such, it is reasonable to conclude that, while subtle differences in microwear textures may reflect differences in background habitats, the wear fabric differences between P. robustus and A. africanus are most reasonably interpreted as having been driven by dietary differences.
The importance of diet in primate ecology has motivated the use of a variety of methods to recons... more The importance of diet in primate ecology has motivated the use of a variety of methods to reconstruct dietary habits of extinct hominin taxa. Dental microwear is one such approach that preserves evidence from consumed food items. This study is based on 44 specimens of Australopithecus africanus from Makapansgat and Sterkfontein, and 66 specimens of Paranthropus robustus from Swartkrans, Kromdraai and Drimolen. These samples enable examination of potential differences between the two assemblages of A. africanus, and among the various assemblages of P. robustus in relation to the paleoenvironmental reconstructions that have been proffered for each fossil site. Sixteen microwear texture variables were recorded for each specimen from digital elevation models generated using a white-light confocal profiler. Only two of these differ significantly between the Makapansgat and Sterkfontein samples of A. africanus. None of the microwear texture variables differs significantly among the samples of P. robustus. On the other hand, P. robustus has significantly higher values than A. africanus for 11 variables related to feature complexity, size, and depth; P. robustus exhibits rougher surfaces that comprise larger, deeper features. In contrast, A. africanus has smoother, simpler wear surfaces with smaller, shallower and more anisotropic features. As for possible habitat differences among the various sites, only a relatively small number of subtle differences are evident between the specimens of A. africanus from Makapansgat and Sterkfontein, and there are none among the specimens of P. robustus from various deposits. As such, it is reasonable to conclude that, while subtle differences in microwear textures may reflect differences in background habitats, the wear fabric differences between P. robustus and A. africanus are most reasonably interpreted as having been driven by dietary differences.
Reconstructions of habitat at sites like Kanapoi are key to understanding the environmental circu... more Reconstructions of habitat at sites like Kanapoi are key to understanding the environmental circumstances in which hominins evolved during the early Pliocene. While Australopithecus anamensis shows evidence of terrestrial bipedality traditionally associated with a more open setting, its enamel has low d 13 C values consistent with consumption of C 3 foods, which predominate in wooded areas of tropical Africa. Habitat proxies, ranging from paleosols and their carbonates to associated herbivore fauna and their carbon isotope ratios, suggest a heterogeneous setting with both grass and woody plant components , though the proportions of each have been difficult to pin down. Here we bring dental microwear texture analysis of herbivorous fauna to bear on the issue. We present texture data for fossil bovids, primates, rodents, and suids (n ¼ 107 individuals in total) from the hominin bearing deposits at Kanapoi, and interpret these in the light of closely related extant mammals with known differences in diet. The Kanapoi bovid results, for example, are similar to those for extant variable grazers or graze-browse intermediate taxa. The Kanapoi suid data vary by taxon, with one similar to the pattern of extant grazers and the other more closely resembling mixed feeders. The Kanapoi primates and rodents are more difficult to associate with a specific environment, though it seems that grass was likely a component in the diets of both. All taxa evince microwear texture patterns consistent with a mosaic of discrete mi-crohabitats or a heterogeneous setting including both tree and grass components.
Previous study has suggested that Australopithecus africanus and Paranthropus robustus have overl... more Previous study has suggested that Australopithecus africanus and Paranthropus robustus have overlapping molar microwear textures, but that A. africanus had a greater spread of anisotropy values, whereas P. robustus had more variable but a higher average complexity. This was taken to suggest overlapping diets, but more tough-food consumption by A. africanus and more hard-object feeding by P. robustus. The basis of that original work was a comparatively small sample, including only ten A. africanus specimens. Here we present data for an expanded sample, including both Sts and Stw specimens (n = 25 individuals) from Sterkfontein Member 4 with specimens from the previous study, to assess within-species variation in A. africanus. We considered only molar teeth, and examined them using standard confocal profilometry and scale-sensitive fractal analyses. Our results for both microwear texture complexity and anisotropy are consistent with the previous study based on the smaller sample. While the new data slightly extend the range of values for anisotropy and complexity, the expanded sample of A. africanus still overlaps with that for P. robustus, but has a higher average anisotropy and lower average complexity. This suggests, again, that compared with P. robustus, A. africanus individuals at Sterkfontein consumed more tough foods, and fewer hard, brittle ones in Member 4 times.
The Laetoli paleoanthropological site in northern Tanzania continues to yield one of the ol... more The Laetoli paleoanthropological site in northern Tanzania continues to yield one of the oldest Australopithecus afarensis collections as well as other well preserved non-hominin primate remains, including primate cercopithecids. The Laetoli primates are highly diversified, including fossil galagines, parapithecids and paracolobines. These primate species are indicative of highly variable depositional environments at Laetoli that would have been more wooded or forested with patches of bushes, thorn scrubs and open habitats. This research presents qualitative descriptions and a comparative computational statistical analysis (PCA and DFA) of odontometrics for the posterior teeth of fossil and extant primates as a way to securely classify recently recovered Laetoli fossil primate remains by the University of Colorado Denver Tanzania field school in paleoanthropology. The statistical analyses show that the posterior teeth can be used to distinguish speciation since tooth size can be indicative of dietary adaptations and habitat preferences. For instance, the PCA yields information on general groupings based on habitat preferences, whereas the DFA shows that the buccal teeth have a higher discriminatory power than the premolars; however M3 has the highest discriminatory ability in deciphering primate species and exhibits the lowest misclassification percentage (15.88%) for all tooth types although it is known that it possess the highest variability in tooth size and shape. The results of this analysis and classification of unknown primate species provides a better understanding of the ecological diversity exploited at Laetoli during the Pliocene and contributes to our understanding of primate diversity and dietary behaviors at Laetoli.
Unlike many other PlioPleistocene paleoanthropological sites in East Africa, the depositional and... more Unlike many other PlioPleistocene paleoanthropological sites in East Africa, the depositional and taphonomic history of vertebrate fossil faunal remains at Laetoli differs significantly in that it is time-averaged with low to moderate energy depositional events. The skeletal representation in the Laetoli bovids’ faunal remains is characterized by a high number of limb elements, especially astragali and calcanei that can be used not only in reconstructing depositional and taphonomic histories but also their locomotor and habitat preferences which provide proxy data for hominin paleoecology at Laetoli during the Upper Laetoli depositional events. We here present some taphonomic, depositional history and paleoecological construction of bovid habitat preferences in relation to hominin distribution and habitat utilization at select localities at Laetoli. Furthermore we use taphonomic and depositional history of the mammalian faunal assemblage at Laetoli to demonstrate how different Pliocene Laetoli was from other comparable sites in East Africa. Bovid astragali and calcanei in this study are used as ecomorphological indicators to piece together habitats that may have been utilized by hominins within the Upper Laetolil Beds depositional events.
Journal of human evolution, Jan 9, 2017
Reconstructions of habitat at sites like Kanapoi are key to understanding the environmental circu... more Reconstructions of habitat at sites like Kanapoi are key to understanding the environmental circumstances in which hominins evolved during the early Pliocene. While Australopithecus anamensis shows evidence of terrestrial bipedality traditionally associated with a more open setting, its enamel has low δ(13)C values consistent with consumption of C3 foods, which predominate in wooded areas of tropical Africa. Habitat proxies, ranging from paleosols and their carbonates to associated herbivore fauna and their carbon isotope ratios, suggest a heterogeneous setting with both grass and woody plant components, though the proportions of each have been difficult to pin down. Here we bring dental microwear texture analysis of herbivorous fauna to bear on the issue. We present texture data for fossil bovids, primates, rodents, and suids (n = 107 individuals in total) from the hominin bearing deposits at Kanapoi, and interpret these in the light of closely related extant mammals with known dif...
The Laetoli paleoanthropological site in northern Tanzania continues to yield one of the oldest A... more The Laetoli paleoanthropological site in northern Tanzania continues to yield one of the oldest Australopithecus afarensis collections as well as other well preserved non-hominin primate remains, including primate cercopithecids. The Laetoli primates are highly diversified, including fossil galagines, parapithecids and paracolobines. These primate species are indicative of highly variable depositional environments at Laetoli that would have been more wooded or forested with patches of bushes, thorn scrubs and open habitats. This research presents qualitative descriptions and a comparative computational statistical analysis (PCA and DFA) of odontometrics for the posterior teeth of fossil and extant primates as a way to securely classify recently recovered Laetoli fossil primate remains by the University of Colorado Denver Tanzania field school in paleoanthropology. The statistical analyses show that the posterior teeth can be used to distinguish speciation since tooth size can be indicative of dietary adaptations and habitat preferences. For instance, the PCA yields information on general groupings based on habitat preferences, whereas the DFA shows that the buccal teeth have a higher discriminatory power than the premolars; however M3 has the highest discriminatory ability in deciphering primate species and exhibits the lowest misclassification percentage (15.88%) for all tooth types although it is known that it possess the highest variability in tooth size and shape. The results of this analysis and classification of unknown primate species provides a better understanding of the ecological diversity exploited at Laetoli during the Pliocene and contributes to our understanding of primate diversity and dietary behaviors at Laetoli.
Journal of human evolution, 2018
The importance of diet in primate ecology has motivated the use of a variety of methods to recons... more The importance of diet in primate ecology has motivated the use of a variety of methods to reconstruct dietary habits of extinct hominin taxa. Dental microwear is one such approach that preserves evidence from consumed food items. This study is based on 44 specimens of Australopithecus africanus from Makapansgat and Sterkfontein, and 66 specimens of Paranthropus robustus from Swartkrans, Kromdraai and Drimolen. These samples enable examination of potential differences between the two assemblages of A. africanus, and among the various assemblages of P. robustus in relation to the paleoenvironmental reconstructions that have been proffered for each fossil site. Sixteen microwear texture variables were recorded for each specimen from digital elevation models generated using a white-light confocal profiler. Only two of these differ significantly between the Makapansgat and Sterkfontein samples of A. africanus. None of the microwear texture variables differs significantly among the sampl...
Journal of Human Evolution, 2018
The importance of diet in primate ecology has motivated the use of a variety of methods to recons... more The importance of diet in primate ecology has motivated the use of a variety of methods to reconstruct dietary habits of extinct hominin taxa. Dental microwear is one such approach that preserves evidence from consumed food items. This study is based on 44 specimens of Australopithecus africanus from Makapansgat and Sterkfontein, and 66 specimens of Paranthropus robustus from Swartkrans, Kromdraai and Drimolen. These samples enable examination of potential differences between the two assemblages of A. africanus, and among the various assemblages of P. robustus in relation to the paleoenvironmental reconstructions that have been proffered for each fossil site. Sixteen microwear texture variables were recorded for each specimen from digital elevation models generated using a white-light confocal profiler. Only two of these differ significantly between the Makapansgat and Sterkfontein samples of A. africanus. None of the microwear texture variables differs significantly among the samples of P. robustus. On the other hand, P. robustus has significantly higher values than A. africanus for 11 variables related to feature complexity, size, and depth; P. robustus exhibits rougher surfaces that comprise larger, deeper features. In contrast, A. africanus has smoother, simpler wear surfaces with smaller, shallower and more anisotropic features. As for possible habitat differences among the various sites, only a relatively small number of subtle differences are evident between the specimens of A. africanus from Makapansgat and Sterkfontein, and there are none among the specimens of P. robustus from various deposits. As such, it is reasonable to conclude that, while subtle differences in microwear textures may reflect differences in background habitats, the wear fabric differences between P. robustus and A. africanus are most reasonably interpreted as having been driven by dietary differences.
The importance of diet in primate ecology has motivated the use of a variety of methods to recons... more The importance of diet in primate ecology has motivated the use of a variety of methods to reconstruct dietary habits of extinct hominin taxa. Dental microwear is one such approach that preserves evidence from consumed food items. This study is based on 44 specimens of Australopithecus africanus from Makapansgat and Sterkfontein, and 66 specimens of Paranthropus robustus from Swartkrans, Kromdraai and Drimolen. These samples enable examination of potential differences between the two assemblages of A. africanus, and among the various assemblages of P. robustus in relation to the paleoenvironmental reconstructions that have been proffered for each fossil site. Sixteen microwear texture variables were recorded for each specimen from digital elevation models generated using a white-light confocal profiler. Only two of these differ significantly between the Makapansgat and Sterkfontein samples of A. africanus. None of the microwear texture variables differs significantly among the samples of P. robustus. On the other hand, P. robustus has significantly higher values than A. africanus for 11 variables related to feature complexity, size, and depth; P. robustus exhibits rougher surfaces that comprise larger, deeper features. In contrast, A. africanus has smoother, simpler wear surfaces with smaller, shallower and more anisotropic features. As for possible habitat differences among the various sites, only a relatively small number of subtle differences are evident between the specimens of A. africanus from Makapansgat and Sterkfontein, and there are none among the specimens of P. robustus from various deposits. As such, it is reasonable to conclude that, while subtle differences in microwear textures may reflect differences in background habitats, the wear fabric differences between P. robustus and A. africanus are most reasonably interpreted as having been driven by dietary differences.
Reconstructions of habitat at sites like Kanapoi are key to understanding the environmental circu... more Reconstructions of habitat at sites like Kanapoi are key to understanding the environmental circumstances in which hominins evolved during the early Pliocene. While Australopithecus anamensis shows evidence of terrestrial bipedality traditionally associated with a more open setting, its enamel has low d 13 C values consistent with consumption of C 3 foods, which predominate in wooded areas of tropical Africa. Habitat proxies, ranging from paleosols and their carbonates to associated herbivore fauna and their carbon isotope ratios, suggest a heterogeneous setting with both grass and woody plant components , though the proportions of each have been difficult to pin down. Here we bring dental microwear texture analysis of herbivorous fauna to bear on the issue. We present texture data for fossil bovids, primates, rodents, and suids (n ¼ 107 individuals in total) from the hominin bearing deposits at Kanapoi, and interpret these in the light of closely related extant mammals with known differences in diet. The Kanapoi bovid results, for example, are similar to those for extant variable grazers or graze-browse intermediate taxa. The Kanapoi suid data vary by taxon, with one similar to the pattern of extant grazers and the other more closely resembling mixed feeders. The Kanapoi primates and rodents are more difficult to associate with a specific environment, though it seems that grass was likely a component in the diets of both. All taxa evince microwear texture patterns consistent with a mosaic of discrete mi-crohabitats or a heterogeneous setting including both tree and grass components.