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Scott
Simpson, Ph.D., from anatomy, part of team that discovers new hominid cranium
in Ethopia
Led by Gona
Project based at CRAFT Stone Age Institute at Indiana University
CLEVELAND (March 24, 2006) – Scientists
conducting palaeoanthropological field research at Gona, in the Afar
Administrative State of Ethiopia, have discovered a significantly complete
cranium of a human ancestor estimated to be Middle Pleistocene in age. The new
hominid was discovered at Gawis (pronounced gow-wees) in the Gona
Paleoanthropological Research Project study area of Ethiopia. The discovery was
reported by Sileshi Semaw, director of the 
Gona Project, who
is based at CRAFT Stone Age Institute,
The new cranium from Gawis appears to be
intermediate between the earlier Homo
erectus and later Homo sapiens
and may be sampling a single lineage. At the discovery site and nearby areas,
significant archaeological collections of Late Acheulean stone tool-making
tradition and numerous fossil animals were found, opening a window into an intriguing
and important period in the development of modern humans. The southwest portion
of the project area near the Gawis River contains the youngest part of the
archive which is estimated to the Middle Pleistocene. Most of the sediments
containing the cranium are sands and silts, not datable by standard geologic
methods. However, the region contains many active and recently active volcanoes
that erupted periodically, blanketing the local landscape with thin,
gray-colored layers of volcanic ash. These volcanic ash layers hold the key to
dating the Gawis cranium and associated stone tools. Some ash layers in the
Gona project area can be directly dated by the 40Ar/39Ar
method, and others, by virtue of their distinctive chemical composition, can be
matched to correlative dated layers outside the Gona area providing the
opportunity to make this one of the best-dated human ancestors notes Jay Quade,
Gona project geologist.
The
discovery of the Gawis cranium and its significance
The cranium was
found by Asahamed Humet (project member) on Feb. 16, 2006, while he and project
scientists were conducting archaeological and geological reconnaissance survey
in the Gawis river drainage basin in the Afar Regional Administration of
Ethiopia. The cranium was found in a small gully at the base of a steep slope
of soft sediments from which it had recently eroded. The specimen includes the
braincase, upper face and upper jaw. Several surface exposed stone tools were
found at the hominid site. Additional contemporary stone tools excavated from
the same stratigraphic level near the hominid site include Late Acheulian
artifacts. A diversity of fossil animals including pigs (two types), zebras,
elephants, multiple types of antelopes, small carnivores including cats, and
numerous rodents were found at the same stratigraphic level as the Gawis
cranium.
“I am thrilled to have a complete cranium
discovered from Gona that can provide key information for understanding the
variation that existed during the Middle Pleistocene,” Semaw said.
Scott Simpson, the project paleontologist
added, “A good fossil provides anatomical evidence that allows us to refine our
understanding of evolution. A great fossil forces us to reexamine our views of
human origins. I believe the Gawis cranium is a great fossil.”
The Gawis cranium comes from a time of
transition to modern humans from African
Homo erectus that is poorly known. The fossil record from
The Gawis cranium provides us with the
opportunity to look at the face of one of our ancestors. Additionally, this
fossil links us with the past by showing a face that is recognizably different
and more primitive than ours. The face and cranium of this remarkable fossil
are recognizably different from that of modern humans, but it bears
unmistakable anatomical evidence that it belongs to our ancestry. The form of
the face and the brain are among the best means for exploring the evolutionary
path of humans and the Gawis cranium preserves both areas. Work is in progress
by the Gona team to determine the age of the cranium and associated
archaeology, and to understand its evolutionary relationships with others known
during the Pleistocene.
Semaw concluded, “I am happy that the
Gona project succeeded to make a new hominid discovery from this least known
time period in human evolution. Gona is a wonderful site, and Ethiopian
paleoanthropology has a lot more to offer to the world. We will keep our heads
up and continue our work, and I am optimistic that we will be rewarded with
more thrilling discoveries for years to come.”
Simpson said, “In human paleontology,
fossils of this quality are exciting because they stretch the boundary of our
understanding and challenge us to develop more robust explanations of human
evolution. The Gawis cranium is one of these rare finds because it is from an
important period during an important transition in our history that clearly
reflects its Homo erectus heritage
yet was on the branch leading to modern humans.”
S.
W. Simpson – Gona Project paleontologist
Scott W. Simpson is the project
paleontologist for the Gona Project and has been with the project since
fieldwork began in 1999. His research specialty is in human evolution, with a
strong interest in the evolution of African mammals during the past 6 million
years.
Simpson is an associate professor in the
Department of Anatomy at the Case Western Reserve University School of
Medicine, where he teaches human anatomy to first- and second-year medical
students. He received his Ph.D. in biomedical sciences, with a specialty in
biological anthropology, in 1992 from
Previous
discoveries by the Gona Palaeoanthropological Research Project
The Gona project area has sediments that
span the last 5.6 million years – a period that has witnessed many evolutionary
and technological changes in human history and Gona has already provided
evidence that allow a better understanding of those changes. The Gona archaeological
sites are known for the discovery of the oldest excavated stone tools in the
world dated to 2.6 million years ago. Early in 2005, members of the Gona
Project announced the discovery of hominids assigned to Ardipithecus ramidus, among the earliest hominid genus in
Support
The research permission for the work in
the Afar is granted by the Authority for Research and Conservation of Cultural
Heritage and the
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