Turkana Basin Institute

Convened by Richard Leakey and organized by the Turkana Basin Institute, the 4th Annual Stony Brook Human Evolution Symposium was held on September 25th before a sold out audience in the beautiful Wang Center auditorium. This year’s symposium focused on the evolution and adaptation of one of the most famous of all human ancestors: Australopithecus. 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. Since that time, species of Australopithecus have been found in many other parts of the continent. Together they date from 4.2 to ~2.5 million years ago. The 2007 Symposium focused on understanding the phylogenetic relations among these many species of Australopithecus as well as their behavioral similarities and differences. The symposium also addressed the biogeography and ecology of this widespread and diverse genus.

Following a warm welcome from University President Shirley Strum Kenny, Richard Leakey (Turkana Basin Institute) gave the first lecture of the day. Prof. Leakey’s talk served as an introduction to many of the issues that would be discussed throughout the day, including the history of important fossil discoveries, ongoing controversies surrounding the interpretation of particular fossils, and potential avenues for future research.

Bill Kimbel (Arizona State University) then introduced the cast of australopithecine characters and their potential phylogenetic relationships. Prof. Kimbel is intimately familiar with the diversity of australopithecine fossils, having been part of various research teams that have discovered numerous specimens in the Hadar region of Ethiopia. Following Kimbel, Ron Clarke (University of Witwatersrand) gave a more detailed description of the variation present among the many Australopithecus finds from South Africa. In particular, Clarke described the context and morphology of an enigmatic and astonishingly complete australopithecine skeleton from Sterkfontein that has become known as “Little Foot.” The next speaker, Meave Leakey (Turkana Basin Institute) also discussed a recently discovered fossil human ancestor from East Africa named Kenyanthropus. Though morphologically distinct from members of Australopithecus, Kenyanthropus was also a bipedal human ancestor that coexisted in East Africa alongside australopithecines. Therefore, fossils of Kenyanthropus are crucial to discussions of early hominin diversity.

Matt Sponheimer (University of Colorado at Boulder) then discussed various lines of evidence that have been used to reconstruct the diet of australopithecines. In particular, he described how microscopic traces on earlier australopithecine teeth from East Africa are very similar to those which develop on the teeth of modern gorillas and chimpanzees, suggesting a diet based on soft foods. However, later australopithecines from South Africa have impressions on their teeth suggestive of a diet more reliant on hard objects, thus providing evidence of dietary diversity among australopithecines. Sponheimer’s talk transitioned nicely into a lecture by Kaye Reed (Arizona State University) on the ecological communities occupied by australopithecines. Through analyzes of the bones of other animals found in the same geological layers as australopithecines, Reed demonstrated that these human ancestors occupied a variety of environmental niches which varied both geographically and temporally.

The final lecture of the symposium, presented by Jack Stern (Stony Brook University), tackled the controversial issue of the locomotor adaptations of Australopithecus. Prof. Stern was among a group of scientists from Stony Brook who suggested in the early 1980s that while australopithecines walked bipedally, they were equally well adapted to life in the trees. Filled with humor, personal anecdotes, and convincing data, Prof. Stern’s talk left the audience wanting more.

There were also several opportunities throughout the day for those attending the conference to interact with the speakers. There were two question and answers sessions when a variety of issues were raised, including what individuals can do to raise awareness about the subject of human evolution. Also, the symposium was followed by a beautiful outdoor reception that provided opportunity to discuss issues with the speakers while enjoying hors d'oeuvres and drinks.

The symposium was followed by a four day long workshop held at the estate of Stony Brook University President Shirley Strum Kenny where numerous researchers from a variety of disciplines discussed the issues raised during the symposium and attempted to identify points of consensus and issues that need further research.