International Research Team Examine ‘Hobbits’ Feet
The ‘Hobbit’ Foot Like No Other In Human Fossil Record — Published in Nature, the International Study is the First Scientific Analysis of the Hobbit Foot — New Analysis Shows ‘Hobbits’ Couldn’t Hustle.
A detailed analysis of the feet of Homo floresiensis—the miniature hominins who lived on a remote island in eastern Indonesia until 18,000 years ago—may help settle a question hotly debated among paleontologists: how similar was this population to modern humans? A new research paper, featured on the cover of the current issue of Nature, may answer this question. While the so-called “hobbits” walked on two legs, several features of their feet were so primitive that their gait was not efficient.
“The hobbits were bipedal, but they walked in a different way from modern humans,” explains William Harcourt-Smith, a Research Scientist in the Division of Paleontology at the American Museum of Natural History and an author on the paper. “Their feet have a combination of human-like and more primitive early hominin traits, some of which are more akin to those in Lucy.” Lucy is an early bipedal but small-brained hominin, or australopithecine, that lived in Africa 3.2 million years ago.
The “hobbits,” excavated from Liang Bua Cave on the island of Flores, were first described in 2004. Known specimens range in age from 90,000 to 18,000 years old, making them contemporaneous with modern humans. This, in combination with the unusually small stature and brain size of H. floresiensis, led to considerable debate among researchers and in the press. Some consider the population a separate species, while others have assessed the fossils as pathological modern humans. But a number of recent analyses of the skull, face, and wrist have found many unusually primitive features among the “hobbits” that are more similar to chimpanzees and Australopithecus, suggesting that the Flores inhabitants represent a remnant population of early hominins.
The anatomy of the foot described in the new paper might finally answer the pathological modern vs. primitive population question. Although the foot is characteristic of a biped—being stiff and having no opposable big toe—many other traits fall outside of the range for modern humans. The H. floresiensis foot is very long in proportion to the lower limb and considerably more than half the length of the thighbone; modern human feet are relatively shorter at about half of the femur’s length. The stubby big toe of the hobbits is another primitive, chimp-like trait. But the pivotal clue comes from the navicular bone, an important tarsal bone that helps form the arch in a modern human foot. The “hobbit” navicular bone is more akin to that found in great apes, which means that these hominins lacked an arch and were not efficient long-term runners.
“Arches are the hallmark of a modern human foot,” explains Harcourt-Smith. “This is another strong piece of the evidence that the “hobbit” was not like us.”
“These particular ‘hobbit’ feet may have never walked into Mordor, but they certainly remind us how little we know about which other hominin species walked out of Africa and the many possible places their feet helped take them,” adds co-author Dr. Matthew Tocheri, of the Smithsonian Institution.
Researchers also assessed the pathology hypothesis by comparing “hobbit” feet to those of typical modern humans and pathological modern specimens such as pituitary dwarfs. While the pathological specimens fell well within the range of modern humans, the “hobbits” did not. This suggests that H. floresiensis was an unusual, isolated population of early hominins.
“The fossil record continues to surprise us,” says William Jungers, Chairman of the Department of Anatomical Sciences at Stony Brook University Medical Center, and an author on the study. “H. floresiensis is either an island-dwarfed descendant of H. erectus that not only underwent body-size reduction but also extensive evolutionary reversals, or, as our analysis suggests, it represents a new species full of primitive retentions from an ancestor that dispersed out of Africa much earlier than anyone would have predicted. Either way, the implications for human evolution are profound.”
In “The foot of Homo floresiensis,” the authors also suggest that despite these feet being dated to the Late Pleistocene age (17,000 years ago), their features together with many other parts of the Homo floresiensis skeleton, might represent the primitive condition for our own genus Homo. This could imply a dispersal event out of Africa earlier than what paleoanthropologists have long thought.
Dr. Jungers points out that “if the feet and skeleton of the ‘hobbits’ are instead the result of ‘island dwarfing’ from the Southeast Asian Homo erectus as some scientists suspect, then an amazing number of evolutionary reversals to primitive conditions had to occur as an unexplained and unprecedented by-product.”
Continued excavations on Flores and other parts of Indonesia, to be led by co-author Dr. Mike Morwood, of the University of Wollongong in Australia, in collaboration with Indonesian scientists from the National Research and Development Centre for Archeology in Jakarta, may unearth an answer to the competing theories on the origins and nature of Homo floresiensis.
The research for this international study was supported by grants from the Australian Research Council, the National Geographic Society, the Wenner-Gren Foundation for Antrhopological Research, the Wellcome Trust and the Leakey Foundation.
In addition to Dr. Jungers of Stony Brook University and W. E. H. Harcout-Smith, Division of Paleontology, American Museum of Natural History; co-authors of the study include: R.E. Wunderlich, Department of Biological Sciences, James Madison University; M.W. Tocheri, Department of Anthropology, Smithsonian Institution; Susan G. Larson, Department of Anatomical Sciences, Stony Brook University Medical Center; T. Sutikna and Rhokus Awe Due, of the National Research and Development Centre for Archeology, Jakarta, Indonesia, and M.J. Morwood, School of Earth and Environmental Sciences, University of Wollongong, New South Wales, Australia.
Sources: American Museum of Natural History / Stony Brook University
Related Links:
- The foot of Homo floresiensis – Nature 459, 81-84 (7 May 2009) | doi:10.1038/nature07989
- Wikipedia: Homo floresiensis
Related Post: Report: ‘Hobbits’ Are New Human Species
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