The research involves multidisciplinary field and laboratory work conducted in the Woranso-Mille study area of the Afar Depression in Ethiopia. The Woranso-Mille paleoanthropological project is relatively new and has started gathering significant fossil hominid specimens from a time period poorly known previously (3.6-3.8 million years ago). This funding supports collaborative research to be conducted by paleontologists, geologists, geochronologists, and paleoecologists from six institutions in the United States and abroad.

Scientists from each institution will coordinate their efforts to understand early hominid diversity between 3.0 and 4.0 million years ago, early Australopithecus paleobiology, taxonomy, and phylogenetic relationships, and establish their paleoenvironments. These will be attained by conducting detailed comparative analysis of the Woranso-Mille hominids enhanced by the use of High-resolution x-ray computed tomography, and isotope analysis in order to test whether morphological differences observed for the Woranso-Mille hominids correlate to isotopic variation that are indicative of behavioral and physiological differences. The paleontologists will further conduct faunal collection directed towards increasing the sample size of all fossil taxa at the site to increase biostratigraphic control, refine paleoenvironmental context of the associated hominids, and identify additional fossiliferous localities. Geologists of the project will establish a refined stratigraphic context for the fossils collected from all of the designated vertebrate localities in the northern part of the study area, establish refined stratigraphy and chronometric ages (using 40Ar/39Ar dating and magnetostratigraphy) for the vertebrate localities and associated fossils, and determine stratigraphic correlations across vertebrate localities within the study area and other paleontological sites in the region. The scientific results from this study will answer questions related to mid-Pliocene hominid diversity, generate new data on the paleobiology of early hominids and their paleohabitat, and increase understanding of mid-Pliocene African vertebrate evolution.

Broader impacts of this project focus on creating training opportunities for undergraduate and graduate students and postdoctoral fellows.

Project Report

The Woranso-Mille paleontological research project is focused on field and laboratory research to examine the anatomy, behavior, relationships, and ecological context of the early hominid species Australopithecus found in north-central Ethiopia and dated to between 3.4 and 3.8 million years ago. The goal of this portion of the large collaborative Woranso-Mille research project was to collect high-resolution micro-Computed Tomography (microCT) image data from important fossils found at various sites within the study area. These microCT data, in turn, allow for detailed study and comparison of anatomical structures in these extinct species. Intellectual Merit: The microCT images indicate that the preservation of the fossils is highly variable between bones and across different sites. Some fossil elements, especially from the KSD VP 1/1 partial skeleton were poorly preserved. The microCT data revealed that the poor preservation extended to the internal bone structural as well. Many of the bones do not have well-preserved internal structures that are useful for understanding behavior and biomechanics. Despite these limitations for some fossil specimens, many of the fossils reveal important details about external and internal anatomical structures. Importantly, the image data allowed us to generate three-dimensional reconstructions of several aspects of the anatomy of these fossils including reconstructing the distorted femur and the pelvic morphology of one of the most complete Australopithecus afarensis fossil skeletons yet found. The reconstructions of the femur reveal that certain biomechanical characteristics of this bone in Australopithecus may have been more similar to apes than humans. The microCT images also provided insight into the distribution of enamel in the teeth of both adult and young juvenile Australopithecus individuals. Studies of the developing molar teeth in a juvenile jaw reveal important details about growth and development in early hominins in East Africa. Broader Impact: This project enhanced the infrastructure for research in biological anthropology by generating a large microCT dataset that will be useful for understanding a variety of important research questions in paleoanthropology and biological anthropology in general. These data will be a valuable asset to a variety of researchers. The project cemented a collaboration between researchers at the Cleveland Museum of Natural History and Penn State University and provided valuable training opportunities for undergraduate and graduate students at Penn State. Two female graduate students received training in image data processing, analysis, and three-dimensional visualization during the course of this project.

National Science Foundation (NSF)
Division of Behavioral and Cognitive Sciences (BCS)
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Elizabeth Tran
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Pennsylvania State University
University Park
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