All,
The following piece is quite interesting to the extent that it presents the
Homo floresiensis debate in a very reasonable, scientific light, avoiding excessive references to idle and less than parsimonious speculations.
It reports on Peter Brown’s plan to pursue his investigation of the so-called “Hobbit” –- a label he does not particularly like –- by looking very seriously into the “island dwarfing” mode of explanation or hypothesis, an approach that he clearly supported in the interview mentioned earlier. For what it is worth, it is in my view the only parsimonious approach that can be taken at this time: one that puts the problem in squarely in the realm of (human) palaeobiogeographical investigation and this, with special attention given to the manifestations of hyper-endemism (including many examples of “dwarfing”) found throughout Wallace’s Line area.
Jacques Cinq-Mars
Scientist to study Hobbit morphing
Anna Salleh
ABC Science Online -- Friday, 17 December 2004
A key hobbit researcher will study the strange evolutionary changes that happen on islands to help explain how the Hobbit came to be so tiny.
He also hopes studying old bones from pygmy humans and animals that evolved on islands will put to rest claims that Hobbits are related to existing pygmies alive today.
On 3 January 2005, Associate Professor Peter Brown of the University of New England will leave for a six-week study of pygmy bones in European and U.K. fossil collections.
Brown wants to try and explain how Homo floresiensis came to be so small when the only other candidates for its ancestor were much larger.
All small animals get bigger and all big animals get smaller, Brown said.
Since Flores is an island, Brown is exploring the theory that H. floresiensis could have dwarfed from a bigger ancestor as a result of isolation there.
So far no possible ancestors have been found on Flores. And when looking at the anatomical features of the Hobbit, scientists are getting an odd picture.
A puzzling picture
The Hobbit's skull, teeth and jaw suggest it was most likely descended from H. erectus, said Brown.
But its long arms, which were uncovered after the main skeleton, and the brain size are more Australopithecine-like. And the hands are like those of the Homo genus.
Brown thinks that this puzzling combination of features may be a result of what happens when creatures get isolated on islands for thousands of years.
Comparing skulls
From left to right: skulls of Homo floresiensis, an Australopithecine and Homo erectus (Image: Anna Salleh)
"It may have these long arms as part of the dwarfing process, because when animals dwarf they don't just become small versions of big ones," he said. "All sorts of very strange things happen."
He said that when deer, goats and sheep dwarf, their eyes move from the side of the head to the front, because they do not have to be as alert to predators.
"So we know environment has an impact but whether it can have this much of an impact is the kind of thing I'm interested in," said Brown.
To explore his theory, he will study bones of pure pygmy humans, including island and rainforest-dwelling ancestors of some groups who still live today in the Andaman Islands in India, and in Africa.
"I want to compare the adaptations in their skeletons with the adaptations in H. floresiensis," said Brown who remains open to the idea it evolved from Australopithecine.
"You don't rule anything out."
One of the simple questions he hopes to answer is whether people who lived in rainforest environments had relatively long arms.
He also wants to firmly exclude the idea that Hobbits are simply a contemporary pygmy.
Pygmy elephants
Brown will also be looking at bones over many thousands of years from animals that have dwarfed on islands, such as elephants once found on the Mediterranean islands of Malta and Crete.
African elephants around 3 metres tall at the shoulder swam to the islands and within 5000 years they were waist-high, said Brown.
This is the fastest dwarfing known. Grazing animals like deer and goats typically took hundreds of thousands of years to do the same thing.
He hopes studying such dwarfing may give him some insight into whether the sorts of things happening on Flores are within the range of what's happened elsewhere in other species.
Brown will also study primate bones to confirm the classification of the hobbit in the genus Homo.
Sick humans?
Brown also hopes to collect evidence for any future paper refuting the theory the Hobbit is just a sick human with microcephaly, a defect that results in a small brain.
"I'll be looking at abnormal pathologically small people with a range of growth and development disorders that can result in people with small brains," he said.
He says the strongest evidence against microcephaly is that there are seven individual hobbits with the same features, including one skull and the remains of two jaws of the same shape.
"We have a population that makes any arguments about pathology even stupider than they were to begin with," he said.
"You don't have a cave full of 30-year-old microcephalics happily bonking away and making babies for God's sake. It's just a complete nonsense. It doesn't happen."
