The identity of the mysterious Homo floresiensis, aka the hobbit, has once again been turned on its head. New research suggests the tiny hominin evolved from an unknown ancestor that was the first to ever venture out of Africa.

Remains of the extinct species were first discovered on the island of Flores in Indonesia just over a decade ago, but there is still fierce debate about where they came from.

The dominant idea has been that H. floresiensis was descended from the larger Homo erectus, an extinct human species that once occupied Asia. Proponents believe ancestors of H. erectus were the first humans to stray out of Africa about 1.8 million years ago.

The theory is that after members of the big-bodied group reached Flores, they gradually shrunk to just 1 metre tall because of the scarce island resources.

Another possibility is that the hobbits were simply short members of our own species – Homo sapiens. The miniature size of the one skull that has been uncovered could be the result of Down syndrome.

Now, the most comprehensive analysis yet suggests the hobbits were, in fact, descended from a mystery ancestor that lived in Africa over 2 million years ago. Some members of this ancestral group remained in Africa and evolved into Homo habilis – the first makers of stone tools. The others moved out of Africa about 2 million years ago – before H. erectus did – and arrived in Flores at least 700,000 years ago.

First to Flores

“As this ancestor spread through south and south-east Asia and then finally onto Flores, it would have gradually changed, finally becoming H. floresiensis,” says Colin Groves at the Australian National University, who co-authored the study.

His team constructed the hobbit’s family tree by carefully comparing skull, jaw, teeth, arm, leg and shoulder fossils with other Homo species and more primitive ancestors. Previous research had only focused on skull and jaw characteristics.

They found that H. floresiensis was far more closely related to H. habilis than to H. erectus or H. sapiens, suggesting it came from an ancient lineage and shared a common ancestor with H. habilis. This is reinforced by its more primitive, diminutive body type.

The hobbit’s ancestors probably died out across Asia when bigger, more complex human species like H. erectus and H. sapiens later emerged from Africa, Groves says. H. floresiensis was probably only able to cling on in Flores for as long as it did because of its isolation, he says. There’s no fossil evidence to indicate that H. erectus ever it made it to the island.

So what happened to H. floresiensis in the end? The species appears to have died out soon after H. sapiens left Africa 60,000 years ago and pushed into Asia. It’s possible that a clash between the two species spelled the end of the mysterious Indonesian hobbits.

Source: New Scientist