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Meet our TINY ancient cousins! Newly-discovered hominin species that lived in Indonesia 700,000 years ago was just 3.2ft tall, study finds
J.R.R Tolkien might have created the world's most famous hobbit almost 90 years ago, but scientists say real-life hobbits are far older than that.
Archaeologists have uncovered the 700,000-year-old fossils of an ancient hominid ancestor of homo floresiensis - a human relative often known as the Hobbits.
The researchers uncovered the fossilised bones of four individuals, including two children in a deep layer of sandstone on the Island of Flores, Indonesia.
By comparing the tiny forearm bone to the size of a modern human, the researchers estimate that this hominid would have stood at just 3.2ft (100cm) tall.
Co-author Professor Adam Brumm of Griffith University says: 'It is now apparent from the tiny proportions of this limb bone that the early progenitors of the "Hobbit" were even smaller than we had previously thought.'
Researchers have discovered that our ancient hominin relatives (pictured) were even smaller than previously thought
Homo floresiensis – an extinct species of human nicknamed the 'Hobbit' – was discovered in 2003, when its skeleton was found in a cave on the island of Flores, Indonesia (artist's impression)
The small hominins gained the nickname 'Hobbits' after J.R.R Tolkien's creations. Pictured Martin Freeman as Bilbo Baggins in The Hobbit
In 2003, researchers discovered the remains of an ancient hominid species in a cave called Liang Bua on the island of Flores, Indonesia.
Named homo floresiensis after the island, these human relatives were just one metre-tall, much smaller than other known early hominins.
Experts believe they lived on the island as recently as 50,000 years ago - when our own species was already established in Australia.
However, since their discovery, scientists have debated where these tiny hominins may have come from and why they evolved to be so small.
Now, Professor Brumm and his co-authors believe they have found evidence which could finally provide an answer.
In their paper, published in Nature Communications, the researchers report the discovery of an extremely rare set of fossils which predate the Liang Bua hominins by 650,000 years.
The skull of homo floresiensis (left) was significantly smaller than a modern human skull (right)
The remains of an ancient relative of homo floresiensis were discovered on the island of Flores, Indonesia (pictured). This is very near to Java where Homo Erectus first evolved
The fossilised upper arm bone (pictured) is the smallest ever discovered in an adult hominin specimen
The researchers made their discovery in an area called Mata Menge which lies 46 miles (75km) to the east of the Liang Bua cave.
The bones were found in a layer of sandstone which had been deposited by a small stream around 700,000 years ago.
The 10 pieces of fossil belonged to four individuals and include teeth and a partial humerus, the upper arm bone.
This arm was far smaller than anything the researchers had expected to find, but digital microscopy of the microstructure revealed that it was from an adult.
Co-author Professor Yousuke Kaifu, of the University of Tokyo, says: 'When I first saw the small humerus, I thought it was a child's bone, but I became curious and was surprised when I looked up its developmental stage.'
At just 211-220 millimetres long, this is the smallest hominid humerus ever discovered in an adult hominid.
Scientists believe that homo floresiensis (artist's impression) lived on the island of Flores until around 50,000 years ago at which time homo sapiens arrived and likely caused the disappearance of this tool-making human relative
By comparing the length of these fossils (pictured) to modern human bones, the researchers estimate that the 700,000 year-old human relative would have been around 1m tall
Previously, researchers had discovered teeth and even a jawbone in this area, but the discovery of the humerus opened the door to new analysis.
Since it is very difficult to estimate the size of an organism by looking at head bones, researchers didn't know how big the hominins at Mata Menge really were.
Co-author Dr Gerrit van de Bergh, of the University of Wollongong, says: 'Initially, we didn’t recognize the humerus fragment, which was broken in several pieces, as belonging to a hominin, because we expected that the toolmaker at Mata Menge would be a large-bodied Homo erectus.
'But after painstaking reconstruction by curator Indra Sutisna, the fossil was recognized as a hominin distal humerus fragment, and a very small one for that matter.'
By comparing the length of the reconstructed humerus to modern humans and primates, the researchers were able to estimate that these ancient hominins would have been 6cm smaller than homo floresiensis.
Researchers had previously found jaw bones and teeth in this area of Flores but had not been able to estimate how large the hominin would have been using these finds. The new discoveries show that these ancient species would have been even smaller than homo floresiensis (pictured)
This bone suggests that the hominins living in this part of the island were 6cm shorter than homo floresiensis which would emerge 650,000 years later
There are currently two rival theories to explain how homo floresiensis came to live on the island.
The first argues that the hominin was a particularly long-surviving relative of an even more ancient African hominin which was very small to begin with.
The alternative argues that this species may have descended from a group of homo erectus which emerged on the nearby Java and somehow became trapped on the island and evolved to become significantly smaller.
This theory gained some support from the fact that other species on the island exhibit unusual body sizes including tiny elephants and giant rats.
However, these latest fossils bear strong similarities to both homo floresiensis and homo erectus.
Professor Brumm says: 'The new fossils strongly suggest that the "Hobbit" story did indeed begin when a group of the early Asian hominins known as Homo erectus somehow became isolated on this remote Indonesian island, perhaps one million years ago, and underwent a dramatic body size reduction over time.'
This chart compares the teeth of homo floresiensis (left: labelled LB1 and LB6/1), the teeth discovered by the researchers (middle: labelled SOA-MM1 and SOA-MM11) and teeth from homo erectus (right: labelled Sangiran 22). This suggests that the hominins found by the researcher were a midpoint between the two species
That discovery shows that homo floresiensis must have evolved its diminutive stature much earlier in its evolutionary history than some researchers had assumed.
Given that homo erectus arrived on the island one million years ago, that would only leave around 300,000 years to dramatically shrink.
However, the researchers point out that since these early hominids shared the island with fearsome 3m-long komodo dragons for thousands of years, their small stature was clearly not an evolutionary disadvantage.
The researchers write: 'This implies that giant reptilians did not represent a serious predation threat for early H. floresiensis or its progenitors.
'The available fossil data imply that small body size had been a functional adaptation for these insular hominins during and slightly beyond the Middle Pleistocene and indeed potentially up until the arrival of H. sapiens [our homo species] on Flores around 50,000 years ago'.