Nature
Published online: 27 October 2004; | doi:10.1038/4311029a

Little lady of Flores forces rethink of human evolution

Rex Dalton

Dwarf hominid lived in Indonesia just 18,000 years ago.



 

 

A new human-like species - a dwarfed relative who lived just 18,000 years ago in the company of pygmy elephants and giant lizards - has been discovered in Indonesia.

Skeletal remains show that the hominins, nicknamed 'hobbits' by some of their discoverers, were only one metre tall, had a brain one-third the size of that of modern humans, and lived on an isolated island long after Homo sapiens had migrated through the South Pacific region.

"My jaw dropped to my knees," says Peter Brown, one of the lead authors and a palaeoanthropologist at the University of New England in Armidale, Australia.

 

 I nearly dropped to my knees at one point examining the specimen. 


 

Paleoanthropologist Peter Brown
University of New England in Armidale, Australia.

The find has excited researchers with its implications - if unexpected branches of humanity are still being found today, and lived so recently, then who knows what else might be out there? The species' diminutive stature indicates that humans are subject to the same evolutionary forces that made other mammals shrink to dwarf size when in genetic isolation and under ecological pressure, such as on an island with limited resources.

 



 

The find has been classed as a new species - Homo floresiensis.

© P. Brown

The new species, reported this week in Nature1,2, was found by Australian and Indonesian scientists in a rock shelter called Liang Bua on the island of Flores. The team unearthed a near-complete skeleton, thought to be a female, including the skull, jaw and most teeth, along with bones and teeth from at least seven other individuals. In the same site they also found bones from Komodo dragons and an extinct pygmy elephant called Stegodon.

The hominin bones were not fossilized, but in a condition the team described as being like "mashed potatoes", a result of their age and the damp conditions. "The skeleton had the consistency of wet blotting paper, so a less experienced excavator might have trashed the find," says Richard Roberts of the University of Wollongong, Australia.

"Only the Indonesians were present at the actual moment of discovery - the Australian contingent had departed back to Oz," says Roberts. He credits Thomas Sutikna of the Indonesian Centre for Archaeology in Jakarta for the excellent handling of the samples. The success has inspired national pride at the centre, the researchers say. "This is very important for Indonesian society," says co-author R. P. Soejono.

 

 It's the most extreme example ever found of human adaptation. 


 

Archaeologist Robert Foley
University of Cambridge, UK

The discovery is prompting increased scrutiny of sites on other Southeast Asian islands, both to look for more of the same species and to place it in context with Homo sapiens and Homo erectus, our closest relative. Homo erectus was found to have lived on the nearby island of Java as long as 1.6 million years ago; the team suggests that the Flores hominins may be their descendants.

 



 

Peter Brown photographs his find.

© P. Brown

Dating more bones could help determine whether the species was a short-lived branch of human evolution or survived for longer. Preliminary dating places it at about 70,000 years ago, but it may extend back 800,000 years. "We were hoping we might find a little hominin from that early," says author Michael Morwood, an archaeologist at the University of New England.

In the meantime, researchers are hoping to find DNA in the bones, which would help to clarify the relationships between species. DNA has previously been extracted from European Neanderthals living in the same time period. But they have so far failed to find DNA in the teeth of the Stegodon found in the same cave, says Brown.

Additional reporting by Michael Hopkin.

Published online: 27 October 2004; | doi:10.1038/news041025-3

A stranger from Flores

Chris Stringer

When a new fossil is found it is often claimed that it will rewrite the anthropological textbooks. But in the case of an astonishing new discovery from Indonesia, this claim is fully justified.



 

The skull of Homo floresiensis is tiny compared to modern day Homo sapiens.

© P. Brown

The conventional view of early human evolution is that the species Homo erectus was our first relative to spread out of Africa, some 2 million years ago. The spread that our cousin achieved is indicated by a 1.8-million-year-old, primitive form of H. erectus found at Dmanisi in Georgia, and by finds at slightly younger sites in China and the Indonesian island of Java. It was not thought that H. erectus travelled any farther towards Australia than this, because although early humans could have walked to Java from Southeast Asia at times of low sea level, the islands east of Java, always separated from it by deep water, seemed beyond their reach.

However, six years ago a team of archaeologists, led by Australian Mike Morwood, published a paper claiming that a site on the island of Flores, 500 kilometres east of Java, contained stone tools dating from about 800,000 years ago1. Many researchers (myself included) doubted these claims, because if they were true they implied that H. erectus had moved beyond Java and might have used boats to do so. Such a development was thought to be unique to Homo sapiens.

When I then heard rumours about the discovery of an early human skeleton in a cave on Flores, I was ready to be surprised. However, nothing could have prepared me for how big (or small) that surprise would be.

Asian fusion

The skeleton found at Liang Bua, a cave on Flores, is of an adult who was only about one metre tall with a brain size of only 380 cubic centimetres. That is less than one-third of the average brain size for a modern human and much smaller even than those of the primitive H. erectus skulls from Dmanisi.

The Flores skull shows a unique mixture of primitive and advanced characteristics. The brain is the same size as a chimpanzee's, the brain-case is low with a prominent brow ridge at the front, and the lower jaw completely lacks a chin. However, as in modern humans, the face is small and delicate. It is tucked under the brain rather than thrust out in front and the teeth are similar in size to our own.

The skeleton shows a similarly strange mixture of features. The hip-bone resembles those of the pre-human African species known as australopithecines (meaning 'southern apes'). But the legs are slight, and enough detail has been preserved to show that this creature definitely walked on two legs, as we do.

Class act

 



 

This skull almost certainly belonged to a woman, who lived 18,000 years ago.

© P. Brown

So what was this strange creature, and what was it doing on Flores? The authors of the two Nature papers2,3 about the discovery and its context have had to make difficult choices in deciding how to classify the creature, although it is clear that this person was definitely not a modern human. The small brain size and the hip-bone shape might favour classification as an australopithecine, whereas the size and shape of the skull might suggest a primitive form of H. erectus.

Given the unique combination of features, the authors have decided to give the specimen a new name: Homo floresiensis. This means, literally, 'man of Flores', although the authors recognize that the Liang Bua skeleton is probably that of a woman.

The researchers argue that this species made the tools found in the Liang Bua cave, and may have preyed on one of the few other mammals that had also managed to reach Flores: a tiny form of the extinct, elephant-like Stegodon.

Of a certain age

It seems that Flores man (or woman) still has one more surprise up its sleeve: its age. Astonishingly, two methods of dating agree in placing the skeleton at only about 18,000 years old. Its ancestors, probably a form of H. erectus, could have reached the island in the hunt for stegodons a million years ago, either by building some kind of boat or by walking across a short-lived land-bridge.

Their resulting isolation and inbreeding may have led them to evolve a small body size, in a process known from other mammals as 'island dwarfing'. Because of climate change or the impact of modern humans, who began to spread from Africa around 100,000 years ago, the strange story of H. floresiensis eventually ended in extinction. But modern humans must surely have encountered this tiny relative of ours, and the discovery shows how much we still have to learn about the story of human evolution.

Chris Stringer is a palaeontologist at the Natural History Museum in London.

 

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References
  1. Morwood M. J., et al. Nature, 392. 173 - 176 (1998). | Article | ISI | ChemPort |
  2. Brown P., et al. Nature, 431. 1055 - 1061 (2004). | Article |
  3. Morwood M. J., et al. Nature, 431. 1087 - 1091(2004). | Article | PubMed |
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Nature
Published online: 27 October 2004; | doi:10.1038/4311043a

Human evolution writ small

Marta Mirazon Lahr & Robert Foley 

Fig 1 full size
Figure 1. Homo floresiensis in the context of the evolution and dispersal of the genus Homo.
a, The new species as part of the Asian dispersals of the descendants of H. ergaster and H. erectus, with an outline of the descent of other Homo species provided for context.

b, The evolutionary history of Homo is becoming increasingly complex as new species are discovered. Homo floresiensis (left) is believed1 to be a long-term, isolated descendant of Javanese H. erectus, but it could be a recent divergence. 1, H. ergaster/African erectus; 2, georgicus; 3, Javanese and Chinese erectus; 4, antecessor; 5, cepranensis; 6, heidelbergensis; 7, helmei; 8, neanderthalensis; 9, sapiens; 10, floresiensis. Solid lines show probable evolutionary relationships; dashed lines, possible alternatives.