Fri May 11, 2012
Real Hobbits: Discovery of New Hominid Shows Diversity of Evolution
Matt Tocheri knows hobbits pretty well: he’s been studying their wristbones for years.
Well, not quite hobbits, per se, but homo floresiensis, a hominid fossil discovered on the island of Flores in Indonesia, which at first glance appeared to be a small version of a modern human. However, researchers argue that these ‘hobbits’ are in fact h. floresiensis, and make up a new branch of the human evolutionary tree.
Tocheri argued just that Thursday night at Linda Hall Library in the last of the Relatively Human Lecture Series. Tocheri's lecture, entitled “The Pleistocene Meets Middle Earth: The Significance of the Indonesian Hobbits,” details his research of the morphology of h. floresiensis wristbones and his conclusion that their uniqueness in this regard proves they are a new species.
This hasn’t been a placid opinion to have—many scientists argued that h. flo was merely a pre-modern human with a pathology such as microcephaly. Also, the hobbit’s surprisingly small brain cavity and the preponderance of stone tools created another catch in previously held evolutionary beliefs: most evolutionary theory holds that once hominids start using tools, their brains start to increase in size. Not for hobbits, apparently.
And so, as J.R.R. Tolkien said, “The hobbits suddenly became, by no wish of their own, both important and renowned, and troubled the counsels of the Wise and the Great.”
Tocheri explained during his lecture that though some think the ‘hobbit’ nickname is unhelpful, he believes it’s a positive element: “They are a kind of human that is very different from us but still very special.”
The area that they were found in is special, too. The island of Flores is located between two special lines: The Wallace line and the Lydekker line that lies between Sunda and Sahul. The area between is known as Wallacea. These lines separate Asia and Australia, and the difference in flora and fauna is remarkable, including h. floresiensis. Tocheri posits that the deep water channels that comprise these lines, and make them hard to cross for species, are yet another reason our hobbits probably aren’t a type of modern human.
H. flo would have been roughly 3 and ½ feet tall, and would have weighed between 30-40 kilograms. They used stone tools, and were presumably hunters, judging from the marks on pygmy stegadon bones found alongside their own.
So how did Tocheri become champion of the hobbits? Tocheri is a paleoanthropologist in the Human Origins Program at the Smithsonian Institution’s National Museum of National History. His research lies in the evolutionary history and functional morphology of the human and great ape family.
Tocheri had the opportunity to examine h. flo’s bones in 2007. With 27 bones in hominid hands, they contain a large portion of the bones in the entire body.
“Wrist morphology distinguishes apes from monkeys, great apes from lesser apes, and African apes and humans from orangutans,” said Tocheri.
Tocheri took this knowledge and made 3-D photos of the h. flo wrist bones in his lab, then compared it to modern human bones, Neanderthal bones, and African apes. The bones were nearly indistinguishable from the African apes, and therefore, he argues, not simply an offshoot of modern humans.
Tocheri welcomes the complications this brings to human evolutionary theory.
“There’s an incredible amount of diversity in human evolution,” he said, “and until you know how diverse the family has been, it’s hard to tell how special humans are.”