Source: BBC

In 2003 a mysterious tiny species of hominin (early human) was discovered on the Indonesian island of Flores. It was given the scientific name Homo floresiensis, but it’s better known by its catchy nickname: “the hobbit”.

Nothing quite like the hobbit had been observed before in two million years of human evolution. For one, fully grown it was only about 3.5ft (1.1m) tall and would have weighed about 25kg. And, even more unusually, its skull was tiny: the hobbit’s brain would have been no larger than a modern chimpanzee’s.

The hobbit may have lived on Flores for about 100,000 years. About 15-18,000 years ago it disappeared forever.

This makes it the most recent other human species that walked the Earth at the same time as us.

Whether this creature represents a unique species or not remains an area of debate among paleoanthropologists. Some say it was simply a modern human with a form of dwarfism. Others have even proposed that the hobbit’s size – and in particular that tiny skull – was the result of a genetic disorder such as microcephaly or Down’s syndrome.

You cannot argue that one feature is the definitive clue

Cut off from the rest of the world on Flores, this isolated habitat is another factor that could have caused it to evolve to such a small size. The island was also home to a dwarf elephant ancestor, for example.

These ideas are heavily debated and a myriad of methods have been used to analyse the shape and size of the hobbit remains.

The problem, says Antoine Balzeau of France’s Natural History Museum, is that many of these assertions focus on aspects of the skull that represent normal variation among hominins.

The team scrutinised the detail contained in the layers of bone of the skull (Credit: Antoine Balzeau)

“You cannot argue that one feature is the definitive clue of the [species] if it’s normal for many other fossils,” Balzeau told BBC Earth.

A further issue, he says, is that many researchers who have studied the hobbit relied on casts or low resolution scans, which don’t preserve important anatomical details.

None of these features could explain the strange shape of the specimen

Balzeau considers the Flores remains to be the most important fossils discovered in recent years, so he wanted to get to the bottom of some of controversies around their identity.

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