Homo floresiensis, an ancient species of human nicknamed ‘hobbits’ found on the island of Flores in Indonesia in 2003, has seen its previous theories about its origin ruled out by Australian scientists in a new study published in the Journal of Human Evolution. The species, which stood about 1 metre tall and weighed about 25 kilograms, was known to live in the area as recently as 54,000 years ago. A major theory about their origin held that they descended from human ancestor Homo erectus, shrinking in stature over hundreds of generations. Another theory was that it wasn’t a new species at all but an early human ancestor with some kind of genetic disorder. But the new study from the Australian National University, which analysed characteristics of the hobbit skeletons, found they were more likely descended from hominids in Africa and could be far older than predicted. Professor Colin Groves, who worked on the study, said the species likely evolved from the older Homo habilis.”We think it very unlikely that it was descended from Homo erectus, and in fact its sister species, that is the one it is most closely related to is Homo habilis, which lived in Africa about 1.5 to 2 million years ago.” The study found several points of difference between Homo floresiensis skeletons and those of Homo erectus.Study leader, Dr Debbie Argue said that the structure of the Homo floresiensis jaw was inconsistent with that of Homo erectus. “We looked at whether Homo floresiensis could be descended from Homo erectus,” she said. “Logically, it would be hard to understand how you could have that regression, why would the jaw of Homo erectus evolve back to the primitive condition we see in Homo floresiensis?” Instead, the Homo floresiensis would have come much earlier, over 1.75 million years ago. It is likely that Homo floresiensis was a sister species of Homo habilis, says Dr Argue.
The two species would have had an ancestor in common. Homo floresiensis would have evolved in the continent of Africa, and later migrated. Another possibility is that the common ancestor of the two is the one to have been displaced from Africa to somewhere else where it would have undergone evolution. Dr Argue and her team studied 133 different characteristics of the Homo floresiensis skull, jaw, teeth, shoulders, legs and arms, and compared them to all other known hominid species. They found that it’s a long surviving cousin of Homo habilis, an early human ancestor with roots in Africa. None of their tests yielded evidence to support the theory that Homo floresiensis evolved from Homo erectus.Dr Argue says one of the most interesting things about the species is that it lived until about 54,000 years ago which is very recent, evolutionarily speaking.”That anything so archaic looking could have been found to have lived so comparatively recently, is one of the things that was so unexpected about this species,” said Dr Argue. One of those archaic looking features was short legs, which made the arms appear long.”Not as long as, say, a chimpanzee, but way outside the range of modern humans,” said Dr Argue.They also had long feet in comparison to their legs, again, much longer than the range seen in modern humans. Homo floresiensis also had shoulders and a face that shrugged forward, said Dr Argue, a mound of bone in the forehead area that extended around the outside of the eye area, and no chin. “Instead, the jaw slopes backwards, and inside it has a shelf of bone that is below the incisors, compared to our jaw that is vertical inside behind the incisors,” said Dr Argue. Overall, Australian National University researchers said they were 99 per cent sure the species was not descended from Homo erectus, and could totally discount the theory that hobbits were malformed modern humans.