These skull caps belonged to the last known members of the Homo erectus species, found in Central Java, Indonesia, Credit to Russell L. Ciochon and Kiran Patel, University of Iowa.
Scientists have identified the last known occurrence of Homo erectus-in Central Java, Indonesia between 117,000 and 108,000 years ago. An ancient ancestor of modern humans that lived in the Pleistocene era, Homo erectus first appeared approximately 2 million years ago.
An international team of researchers including the University of Alberta's John-Paul Zonneveld applied modern dating technology to a group of fossils originally found in the 1930s. The fossils include 12 skull caps and 2 lower leg bones found in a bone bed 20 metres above the Solo River at Ngandong, Central Java, Indonesia.
"Uncertainty of the age of the Ngandong Homo erectus beds has prevented us from accurately assessing the relationship of these early humans to other human species," said Zonneveld, professor in the University of Alberta's Department of Earth and Atmospheric Sciences. "It is also intriguing that these dates indicate that Homo erectus overlapped temporally with one or more other human species."
The fossils are part of a mass death event that occurred as a result of a change in climate. Approximately 130,000 years ago, Indonesia's climate shifted from dry grasslands to tropical rainforest, and the Homo erectus species could not adapt. It is here that they went extinct. According to the study, the bone bed was formed when the remains were washed into the river and deposited downstream.
"This was an exciting project to be involved in. I was honored to be able to contribute to analyses of the fauna associated with Homo erectus at Ngandong," added Zonneveld.
The research was led by Russell L. Ciochon from the University of Iowa. The 12-member team included researchers from UAlberta, as well as the Institute of Technology in Bandung; the University of Wollongong; the University of Texas-Austin; Griffith University; Southern Cross University; the University of Oxford; the Geological Agency; the University of Queensland in Brisbane; the University of New England; the University of Copenhagen; Minnesota State University-Mankato; Bluestone Heights; Rutgers University; Indiana University; and Illinois State University.
The paper, "'Last appearance of Homo erectus at Ngandong, Java, 117,000-108,000 years ago," was published in Nature (doi: 10.1038/s41586-019-1863-2).