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Rethinking the Hobbits of Indonesia [Preview]

The mini human species found in Indonesia turns out to be even stranger than previously thought and complicates the story of our ancient past
A Perplexing Pastiche

Nevertheless, recent analyses are causing even the proponents to rethink important aspects of the original interpretation of the discovery. The findings are also forcing paleoanthropologists to reconsider established views of such watershed moments in human evolution as the initial migration out of Africa by hominins (the group that includes all the creatures in the human line since it branched away from chimpanzees).

Perhaps the most startling realization to emerge from the latest studies is how very primitive LB1's body is in many respects. (To date, excavators have recovered the bones of some 14 individuals from the site, but LB1 remains the most complete specimen by far.) From the outset, the specimen has invited comparisons to the 3.2-million-year-old Lucy—the best-known representative of a human ancestor called Australopithecus afarensis—because they were about the same height and had similarly small brains. But it turns out LB1 has much more than size in common with Lucy and other pre-erectus hominins. And a number of her features are downright apelike.

A particularly striking example of the bizarre morphology of the hobbits surfaced in May 2009, when researchers led by William L. Jungers of Stony Brook University published their analysis of LB1's foot. The foot has a few modern features—for instance, the big toe is aligned with the other toes, as opposed to splaying out to the side as it does in apes and australopithecines. But by and large, it is old-fashioned. Measuring around 20 centimeters in length, LB1's foot is 70 percent as long as her short thighbone, a ratio unheard of for a member of the human family. The foot of a modern human, in contrast, is on average 55 percent as long as the femur. The closest match to LB1 in this regard, aside from, perhaps, the large-footed hobbits of Tolkien's imagination, is a bonobo. Furthermore, LB1's big toe is short, her other toes are long and slightly curved, and her foot lacks a proper arch—all primitive traits.

“A foot like this one has never been seen before in the human fossil record,” Jungers said in a statement to the press. Characteristics of the pelvis, leg and foot make clear that the hobbits walked upright. But with their short legs and relatively long feet, they would have had to use a high-stepping gait to avoid dragging their toes on the ground. Thus, although they could probably sprint short distances—say, to avoid becoming dinner for one of the Komodo dragons that patrolled Flores—they would not have won any marathons.

If the foot were the only part of the hobbit to exhibit such primitive traits, scientists might have an easier time upholding the idea that H. floresiensis is a dwarfed descendant of H. erectus and just chalking the foot morphology up to an evolutionary reversal that occurred as a consequence of dwarfing. But the fact is that archaic features are found throughout the entire skeleton of LB1. A bone in the wrist called the trapezoid, which in our own species is shaped like a boot, is instead shaped like a pyramid, as it is in apes; the clavicle is short and quite curved, in contrast to the longer, straighter clavicle that occurs in hominins of modern body form; the pelvis is basin-shaped, as in australopithecines, rather than funnel-shaped, as in H. erectus and other later Homo species. The list goes on.

Indeed, from the neck down LB1 looks more like Lucy and the other australopithecines than Homo. But then there is the complicated matter of her skull. Although it encased a grapefruit-size brain measuring just 417 cubic centimeters—a volume within the range of chimpanzees and australopithecines—other cranial features, such as the narrow nose, mark LB1 as a member of our genus, Homo.

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