Science reports:

In what some scientists are calling a “one-in-a-million find,” archaeologists have discovered a cache of butchered rhino bones and dozens of stone tools on the Philippines’s largest island, Luzon. The find pushes back the earliest evidence for human occupation of the Philippines by more than 600,000 years, and it has archaeologists wondering who exactly these ancient humans were—and how they crossed the deep seas that surrounded that island and others in Southeast Asia.

“The only thing missing is the hominin fossil to go along with it,” says archaeologist Adam Brumm, of Griffith University in Nathan, Australia. He’s the one who set the odds for what he calls a “very exciting discovery,” but he wasn’t involved with the work.

Researchers found 75% of a fossilized rhino skeleton—ribs and leg bones still scarred from the tools that removed their meat and marrow—lying in ancient mud that had long since buried an even older river channel. To determine the site’s age, researchers dated the enamel in one of the rhino’s teeth, as well as quartz grains embedded in the sediment layers above and below the bones, using electron spin resonance (ESR), which measures the buildup of electrons as a material is exposed to radiation over time. The team dated the bottom sediment layer to about 727,000 years old, the rhino tooth to about 709,000 years old, and the top sediment layer to about 701,000 years old. Several independent experts say they were impressed by the team’s careful use of the technique. “They’ve nailed it,” says Alistair Pike, an archaeological dating expert at the University of Southampton in the United Kingdom.

So who were these ancient people? They couldn’t have been our own species, Homo sapiens, which evolved in Africa hundreds of thousands of years later. The most likely bet is H. erectus, an archaic human species that first evolved nearly 2 million years ago and may have been the first member of our genus to expand out of Africa, the team writes today in Nature. [Continue reading…]