【化石】ホビットの年代が修正される

New excavations in Liang Bua cave on the Indonesian island of Flores suggest that the diminutive hominin Homo floresiensis (nicknamed the ‘Hobbit’) disappeared much earlier than previously thought. The study, published in Nature this week, indicates that H. floresiensis used the cave between 190,000 and 50,000 years ago, and not until as recently as around 12,000 years ago as previously interpreted.

Fossil remains of H. floresiensis, a primitive hominin species, were discovered in sediments at Liang Bua in 2003. The deposits, which also included associated stone artefacts and remains of various extinct animals, were calculated to be about 12,000 to 95,000 years old. These surprisingly recent ages suggested that H. floresiensis may have survived until long after modern humans reached Australia, around 50,000 years ago.

Thomas Sutikna and colleagues - including many members of the original research team - report new stratigraphic and chronological evidence from Liang Bua cave that does not support the previously calculated dates for H. floresiensis. The authors conducted new excavations during 2007-2014, exposing parts of the cave not seen in the original excavations, and find that the layers of sediment in the cave are not deposited evenly. They date the skeletal remains of H. floresiensis and the deposits containing them to about 100,000 to 60,000 years ago, whereas stone artefacts attributable to this species range from about 50,000 to 190,000 years of age. Whether H. floresiensis survived long enough to encounter modern humans remains an open question.