Newswise — In an article published in the October issue of the Journal of Human Evolution (http://www.uiowa.edu/~anthro/documents/1.5-million-Homo-erectus-jaw.pdf), the team announced the discovery of a 1.5 million-year-old upper jaw of the human ancestor Homo erectus. Found at Sangiran (Sang-GRR-awn) on Indonesia's Java Island, the jaw is the oldest reputably dated example of "Java Man," the Homo erectus type originally discovered in 1891.

The find came from Sangiran expeditions conducted from 1998 through 2008 and co-led by UI Professor Russell L. Ciochon (sha-HAWN) and ITB Professor Yahdi Zaim (zye-EEM). In 2001, UI Associate Professor of Geoscience E. Arthur Bettis III joined the team to study the stratigraphy, sedimentology and soils in order to reliably date the Sangiran site.

The upper jawbone (fossil maxilla) was discovered as the team studied the geology and dating of the Sangiran lower fossil beds. The new fossil is the first Java specimen found in beds under direct geological study, making its provenance incontrovertible. The UI-ITB team has published several peer-reviewed papers dating the Sangiran lower beds to 1.5 million years ago.

Ciochon notes that the new fossil teeth contained within the jawbone show similarities to Homo erectus teeth found in East Africa and Western Eurasia. They are less like those of China's "Peking Man" -- Homo erectus teeth found in Northeast Asia.

Ciochon said that East Asia's two Homo erectus groups (Java and China) may have had separate geographic origins.

"Our team's find at Sangiran is one of several recently discovered human fossils, such as the so-called 'Hobbit' -- an island-dwarfed species of early human -- of the Indonesian island of Flores, as well as the discovery of a unique ancient human DNA lineage at a site in Siberia called Denisova, that has put East Asia in the scientific spotlight," Ciochon said.

"We are now gaining a greater appreciation for the complexity of human evolution in the region, and our research at Sangiran provides yet another line of evidence in an ever-growing mass of data that will help shed light on this faintly illuminated region in our distant human past," he said.

Ciochon is a professor in the UI Department of Anthropology in the College of Liberal Arts and Sciences (CLAS). Other CLAS co-authors are Associate Professor Robert Franciscus and graduate students K. Lindsay Eaves and Hannah Marsh. ITB co-authors are Yan Rizal and Aswan. Other co-authors are Assistant Professor Joshua Polanski, Department of Anthropology, University of Arkansas (2010 CLAS Ph.D. graduate); Professor Frederick Grine, Departments of Anthropology and Anatomical Sciences, Stony Brook University, N.Y.; Roy Larick, Helios Laser, Cleveland, Ohio; and Matthew Heizler, New Mexico Bureau of Mines and Mineral Resources, Socorro, N.M.

The project was funded by the L.S.B. Leakey Foundation and the following UI sources: Center for Global and Regional Environmental Research; Central Investment Fund for Research Enhancement in the Office of the Vice-President for Research; Collaborative Interdisciplinary Projects Initiative in the Office of the Vice President for Research; Office of the Dean, CLAS; and the Human Evolution Research Fund at the University of Iowa Foundation.

STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 371, Iowa City, Iowa 52242-2500