“Hobbits” Disappeared Earlier Than Previously Thought

April 1, 2016

The mysterious hominin known as the “Hobbit” died out far earlier than previously thought, scientists have learned. The revised age, published today in the journal Nature, could help resolve, or reignite, controversies over the diminutive fossil’s origins. It also raises some intriguing questions about why Homo floresiensis vanished—and what role our own species might have played in its demise.

When the discovery of 3-foot-tall Homo floresiensis and its grapefruit-sized head was announced in 2004, the tiny hominin’s odd mix of ancient and more modern physical features captured the public’s imagination and created controversy among scientists tasked with figuring out exactly what kind of creature the unusual bones represented.

Excavations on the Indonesian island of Flores have now revealed that Homo floresiensis called Liang Bua cave home between 190,000 and 50,000 years ago, rather than as recently as 12,000 years ago, which was the surprisingly late date previous research had suggested.

The digs, carried out between 2007 and 2014 by many members of the research team that first discovered the fossil, gradually exposed new parts of the cave only to discover that, thanks to eons of erosion, the sediment layer cake under its floor is unevenly distributed. As teams excavated from the cave’s mouth back toward the middle, it became evident that older deposits had been eroded prior to 20,000 years ago and gradually covered again by new sediments since.

Those younger sediments confused the original dating efforts. Scientists incorrectly associated the Homo floresiensis fossils with the more recent layer, says co-author Thomas Sutikna of the University of Wollongong in Australia, when it’s now clear that they were actually buried in the older layer of sediment.

The bones themselves were also reevaluated for this study with uranium-series dating, which charts the decay of uranium in bones to determine how long they’ve been buried.

Most theories of Homo floresiensis’ origins suggest they are the descendants of an early hominin dispersal. Co-author Matt Tocheri, of the Smithsonian’s National Museum of Natural History and Lakehead University in Thunder Bay, Ontario, says there are two main possibilities.

“The first is that Homo floresiensis is the descendant of Asian Homo erectus, and if this is true, then it implies the smaller body and brain size of Homo floresiensis probably evolved in isolation on the island. The alternative,” he says, “is that Homo floresiensis is the descendant of another pre-modern species of Homo that may have been smaller-bodied and smaller-brained to begin with when it reached the island.”

Tocheri notes that the new ages won’t do much to move the needle from one of these options to the other—only the discovery of more fossils will do that. “If there was a book that chronicled the entire evolutionary history of Homo floresiensis, then it would be like we have only a few tattered and torn pages with the rest of the pages missing but hopefully not lost forever,” he says.

Some scientists, though a distinct minority, maintain that Homo floresiensis isn’t a new species at all but an abnormal, dwarfed member of our own Homo sapiens suffering from some ancient pathology like cretinism, microcephaly or Down’s syndrome. ( Well…..)

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