Diversity in Australopithecus: Tracking the Earliest Bipeds
September 25, 2007
Stony Brook University
The 1925 discovery, in South Africa by Raymond Dart, of a small creature he named Australopithecus africanus showed that our early ancestors were from the continent of Africa. While controversial at the time, it turned interest from exploring for human ancestors in Asia and Europe to Africa.
Since that time, species of Australopithecus have been found in many other parts of the continent. A. afarensis has been recovered in Tanzania, Ethiopia, and Kenya; A. bahrelghazali in Chad; A. garhi in Ethiopia; A. anamensis and the related genus Kenyanthropus in Kenya, and many more A. africanus fossils have been recovered in South Africa. This collection has often been grouped under the name “gracile australopithecines” and they range in time from 4.2 to ~2.5 million years ago.
This Symposium and Workshop focuses on understanding the phylogenetic relations among these many species of Australopithecus as well as their similarities and differences. We will explore the phylogeny of the group with an eye towards understanding the tempo and mode of evolution through this time period. While A. anamensis–A. afarensis has been shown to be a continuous lineage, what is the relationship to A. africanus and to Kenyanthropus? What is the relationship between A. bahrelghazali and its more eastern relatives? Which one of these species likely gave rise to Homo? What is the relationship between these taxa and the more robust species ?
The symposium and workshop also addresses biogeography and ecology of this widespread and diverse genus. Were different species ingabiting different environments? Were there ecological differences between hominins living in the more temperate southern African region and those around the equator? Is there any evidence of geographic connections between species or were they separated by major barriers? Do other Pliocene mammals show similar patterns of distribution? How is the fossil record biased by the nature of the geological deposits in which the fossils have been recovered?.
Finally, the participants investigated many aspects of the behavior and life history of Australopithecus. We now have many insights into the growth and development of this genus through first find of the Taung child, A. africanus, in 1925, and the new A. afarensis child, “Selem,” announced in 2006. Did these early hominins have a human-like or ape-like pattern of growth? What do we know about the diet of different species? The locomotor behavior of Australopithecus has been a subject of ongoing debate since the initial discovery. Everyone now agrees that these early hominids walked uporight on two legs, but did they also spend a large part of their life in trees? What are the differences and similarities between different species? By addressing these and other questions, the workshop participants summarized the current areas on consensus and disagreement, and to identify productive avenues for future research.
|Zeresenay Alemseged is a senior researcher in the Department of Human Evolution at the Max Plank Institute for Evolutionary Anthropology. He is most interested in events surrounding the origin and diversification of early hominins and the underlying environmental factors that are responsible for these processes. His research program focuses on the discovery and interpretation of hominin fossil remains and their environments with emphasize on fieldwork designed to acquire new and much needed data on early hominin skeletal biology, environmental context, and behavior.|
|Kay Behrensmeyer is a Research Curator in the Department of Paleobiology, National Museum of Natural History, Smithsonian Institution. Her career has focused on the geological context, taphonomy, and paleoecology of vertebrate faunas and associated hominins in East Africa. Her field study areas include the Turkana Basin, Tugen Hills, and Olorgesailie Basin in the rift valley of Kenya (Plio-Pleistocene), and the Hadar Formation (Pliocene) of Ethiopia, as well as the Siwalik sequence (Miocene) of northern Pakistan.|
|Frank Brown, Dean of the University of Utah’s College of Mines and Earth Sciences, is a key figure in African geology. His analysis of the age and stratigraphy of deposits in Africa’s Turkana Basin has made possible the dating of many fossil hominids, including Australopithecus anamensis, Kenyanthropus platyops, Homo erectus, and the earliest Homo sapiens.|
|Ronald Clarke is Reader in Palaeoanthropology at the University of the Witwatersrand, Johannesburg, and is Director of Excavations at the Sterkfontein Caves, the Australopithecus site with which he has been involved since 1973. His early career was in East Africa where he worked for Dr. Louis and Dr. Mary Leakey, specializing in the cleaning and reconstruction of fossil hominids. He is currently excavating a 3.3-million-year-old Australopithecus skeleton in the Sterkfontein Caves.|
|John Fleagleis Distinguished Professor of Anatomical Sciences at Stony Brook University. His research involves many aspects of primate and human evolution, including comparative anatomy, biogeography, ecology, and phylogeny. His most recent field work has been in Ethiopia, Egypt, Argentina, and India.|
|Robert A. Foley is Director of the Leverhulme Centre for Human Evolutionary Studies at the University of Cambridge. His research is concerned with the pattern of human evolution in terms of evolutionary processes. At one level this relates specifically to the evolution of adaptive behaviours and morphologies during the course of human evolution, in relation to environmental and socioecological context of fossil hominins. At another level it is concerned with the integration of adaptive microevolutionary processes with macroevolutionary patterns (speciation, diversity, and extinction).|
|Adam Gordon is a research postdoctoral fellow at the Center for the Advanced Study of Hominid Paleobiology at George Washington University. His research focuses on the role of sexual selection and resource stress on the evolution of body size and size dimorphism within fossil hominins and living primates, and the study of size and shape variation in the hominin fossil record. He is particularly interested in how various aspects of primate biology (mass, postcranial size, canine size, etc.) differ in their sex-specific response to selective forces.|
|Frederick Grine is Professor of Anthropology at Stony Brook University. His research focuses on the reconstruction of early hominid dietary habits from the analysis of dental microwear, and the phylogenetic relationships among species of Australopithecus, Paranthropus, and Homo as deduced from fossil skulls and teeth. Of particular interest has been the evolutionary history of the so-called “robust” australopithecines–members of the genus Paranthropusthat flourished in Africa between about 2.5 and 1.2 million years ago.|
|Elizabeth Harmon is Assistant Professor of Anthropology at Hunter College, City University of New York. She is interested in the evolutionary history, ecology, and behavior of Pliocene and Pleistocene hominins. Her research focuses on the postcranial skeleton from which patterns of sexual dimorphism and the character of bipedal locomotion can be deduced. She has conducted field research in the Afar Region and co-directs a field project in southern Ethiopia.|
|Terry Harrison is Professor and Associate Chair of Anthropology at New York University, as well as the Director of the Center for the Study of Human Origins. His research interests include the systematics, paleobiology, paleoecology, and biogeography of Miocene and Pliocene hominoids, including hominins. He directs paleontological and geological investigations at the mid-Pliocene hominin locality of Laetoli, northern Tanzania. Other interests include comparative anatomy, vertebrate paleontology of Africa, reconstructing locomotor and dietary behavior, taphonomy, and Quaternary Southeast Asia.|
|Andy Herries is a speleological and archaeological scientist specialising in the application of geomagnetic methods to reconstructing stratigraphy, palaeoclimate, and chronology of hominin and Stone Age sites as well as behavior related to fire and ochre use. He is currently a post-doctoral fellow at the University of New South Wales (Sydney, Australia). He has worked extensively on the speleological evolution, magnetostratigraphy, and dating of Australopithecine-bearing palaeocave deposits in South Africa.|
|William Jungers is Professor and Chair of Anatomical Sciences at Stony Brook University. His interests include functional anatomy and biomechanics, morphometrics, the evolution of Malagasy primates, and early hominid locomotion. His research is concerned with functional, mechanical and ontogenetic aspects of musculoskeletal design in living and fossil primates, ranging from subfossil lemurs to early hominids.He is the editor of Size and Scaling in Primate Evolution and coeditor of Reconstructing Behavior in the Primate Fossil Record.|
|William H. Kimbel is Professor in the School of Human Evolution and Social Change at Arizona State University and Science Director of the Institute of Human Origins. He conducts field, laboratory, and theoretical research in paleoanthropology, with a primary focus on Plio-Pleistocene hominid evolution in Africa. He has undertaken field and laboratory research in Ethiopia (Hadar) and Tanzania (Olduvai Gorge), as well as in Kenya, South Africa, and Tunisia. He is specifically interested in the application of evolutionary and systematic theory to paleoanthropological problems.|
|Francis Kirera is a Postdoctoral Research Associate at Stony Brook University’s Turkana Basin Institute and an affiliate researcher at the National Museums of Kenya, Paleontology Department. His research interests focus on Plio-Pleistocene hominin paleoecology through the study and discovery of associated fauna. Other interests include spatial analysis and modeling of the Plio-Pleistocene fauna paleohabitats at Koobi Fora sites, Northern Kenya. He has participated in several paleontological field expeditions in Kenya. He just received his PhD in Environmental Dynamics at the University of Arkansas.|
|Susan Larson is Professor of Anatomical Sciences at Stony Brook University. Her research focuses on the functional interpretation of musculoskeletal morphology of humans and nonhuman primates. Most of her work involves using laboratory methods to test hypothesized form/function relationships in order to more confidently reconstruct the behaviors of extinct primate species. She has recently been applying her knowledge of forelimb functional morphology to the analysis of Homo floresiensis, the newly discovered diminutive hominids from the Island of Flores.|
|Meave Leakey is Professor of Anthropology and Anatomical Sciences at Stony Brook University; Explorer-in-Residence, National Geographic Society; co-director, Koobi Fora Research Project; and Research Associate, National Museums of Kenya. She has worked annually in the Turkana Basin since 1969. Current field research is focused on the time of emergence of Homo erectus. Meave Leakey impressed the world with her 1999 discovery of a 3.5 million-year-old skull and partial jaw believed to belong to a new branch of early hominids. Dr. Leakey named the new genus Kenyanthropus platyops.|
|Charles Lockwood is Lecturer in Human Evolution in the Department of Anthropology at University College London. He conducts research on early hominin taxonomy, evolutionary relationships, broader patterns of adaptation in primates, and the relationship of sexual dimorphism to inferences about social behavior. In each case, quantitative/morphometric methods figure prominently. Lockwood’s current work focuses especially on fossils from the Plio-Pleistocene sites of Sterkfontein and Drimolen in South Africa, and Hadar in Ethiopia.|
Fredrick Kyalo Manthi is a Senior Research Scientist in the Department of Palaeontology at the National Museums of Kenya and a Post-doctoral Fellow at Stony Brook University. He received his PhD in 2006 from the University of Capetown. He has worked in many parts of the Turkana Basin. His main research interests are in the analysis of Pliocene and Pleistocene micromammals from Africa and their implications for reconstructing paleoenviroments during the course of hominid evolution.
|Kaye E. Reed is Associate Professor and Associate Director of the School of Human Evolution and Social Change at Arizona State University. Her main research interest is in the ecological context of primate and hominin evolution through identification and analyses of mammalian fauna and communities from Plio-Pleistocene hominin localities. Current field research is focused on hominin sites in the Afar Region of Ethiopia, and cave localities in Spain and Morocco.|
|Gary T. Schwartz is Assistant Professor in the School of Human Evolution and Social Change at Arizona State University and a Research Scientist of the Institute of Human Origins. His main interests are in the evolutionary history of primate growth and development, with a primary focus on how the development and eruption of teeth can be used to reconstruct aspects of life history. Currently, he is working on a range of projects including reconstructing aspects of growth in Eocene primates, Miocene hominoids, and in living and recently extinct Malagasy lemurs.|
|John Shea is Associate Professor of Anthropology at Stony Brook University. His research interests include paleolithic archaeology and paleoanthropology of the Near East, Africa, and Europe; early hominin adaptive radiations; origin of modern humans; Neandertals; lithic technology; and experimental archaeology. He has a specific interest in stone tools and other primitive tools, and he teaches a course in Primitive Technology which examines the technological adaptations of hunter-gatherer societies and their consequences for biological and behavioral evolution.|
|Matt Sponheimer‘s research focuses on investigating the ecology of early hominins in Africa using biogeochemical methodologies. He is currently co-director of a multi-disciplinary project investigating the community paleoecology of Australopithecus africanus at Makapansgat Limeworks, South Africa, and co-director of a research group examining the neoecology of large mammals in South Africa’s Kruger National Park. His other projects include using heavy isotopes to investigate early hominin land use at Olduvai Gorge and the Sterkfontein Valley.|
|Jack Stern is Distinguished Teaching Professor in the Department of Anatomical Sciences at Stony Brook University. His research focuses broadly on primate locomotor evolution, and more specifically on the origin of bipedalism among hominins. He has analyzed fossil hominin postcranial material from Ethiopia, Kenya, and Tanzania. His work has contributed significantly to our understanding of the dynamic locomotor adaptations of Australopithecus.|
|David Strait is a paleoanthropologist at the University at Albany. His research includes reconstructing the phylogeny of early humans; using engineering methods to understand how the facial skeleton of humans and other primates withstand and adapt to the forces imposed by chewing; and paleontological fieldwork in Zambia. Aside from these major projects, Dr. Strait has written about the ecological adaptations of early humans and the origin and evolution of bipedalism.|
|Carol Ward is Professor in the Integrative Anatomy group in the Department of Pathology and Anatomical Sciences at the University of Missouri, Columbia. Her research focuses on the evolution of locomotor anatomy and behavior in Miocene and Pliocene hominoids. She is particularly interested in the bones of the torso, especially the vertebral column, and also is involved with research on clinical conditions of the lumbar spine.|