Surprising origins of Indonesian ‘hobbits’ uncovered

By Ellen Rykers April 21, 2017
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The miniature human species now has a place on the Homo family tree – and it’s more ancient than we thought.

A NEW, DETAILED ANALYSIS of the fossil bones of Homo floresiensis – an extinct human species first unearthed on the Indonesian island of Flores in 2003 – has revealed surprising links with the ancient hominid Homo habilis.

Researchers found that the pint-sized extinct human species, nicknamed ‘hobbits’ for their diminutive 1m height, occupy an unexpectedly primitive spot on the human evolutionary tree.

The scientists compared 133 characteristics of the H. floresiensis bones with other members of the human family, closely examining the skull, jaws, teeth, arms, legs and shoulders.

Their results discredit the widely accepted theory that hobbits descended from H. erectus, found on the nearby island of Java. Instead, the data suggest that hobbits, which lived on Flores until about 54,000 years ago, are most closely related to H. habilis, a hominid species dating to 1.75 million years ago and known only from Africa.

hobbit reconstruction

A reconstruction of the face and body of the ‘Hobbit’ (H. floresiensis). (Image: Katrina Kenny)

“The analyses show that on the family tree, Homo floresiensis was likely a sister species of Homo habilis. It means these two shared a common ancestor,” explained Dr Debbie Argue, an anthropologist from the Australian National University (ANU) and lead author of the study.

“It’s possible that Homo floresiensis evolved in Africa and migrated, or the common ancestor moved from Africa then evolved into Homo floresiensis somewhere,” she said.

No link found to Homo erectus

This ancient African origin surprised the research team. Early evidence suggested the ‘hobbits’ likely evolved from a dwarfish version of their larger geographic neighbour, H. erectus.

“We looked at whether Homo floresiensis could be descended from Homo erectus,” said Debbie. “We found that if you try and link them on the family tree, you get a very unsupported result. All the tests say it doesn’t fit – it’s just not a viable theory.”

“It was surprising,” added Professor Colin Groves, palaeoanthropologist at ANU and co-author of the study. “There have been ideas that Homo floresiensis was a dwarfed version of Homo erectus, but this is really excellent evidence that Homo habilis is actually its closest relative.”

Statistical analysis further bolstered the hobbit-habilis connection, according to co-author Professor Mike Lee.

“When we did the analysis there was really clear support for the relationship with Homo habilisHomo floresiensis occupied a very primitive position on the human evolutionary tree,” said Mike, a palaeontologist at Flinders University and the South Australian Museum.

“We can be 99 per cent sure it’s not related to Homo erectus and nearly 100 per cent it isn’t a malformed Homo sapiens,” he added.

While these findings provide another piece in the evolutionary puzzle, there are still plenty of enigmas to unravel, according to Colin.

“Exactly which fossils belong to Homo habilis is not entirely clear,” he said. “It’s a bit controversial. That’s probably the next project we’ll have to try and sort out.”

Meanwhile, more hobbit specimens will need to be uncovered for further study.

“Only one anatomical part – the lower jaw – is actually represented by more than one hobbit specimen,” said Colin. “So we don’t really know the full range of variation.”

The research appears in the Journal of Human Evolution.