In 2003, a team of Australian and Indonesian researchers led by Peter Brown dug down into the floor of a cave called Liang Bua and uncovered a skull with an associated skeleton (LB 1) and the skeletal remains of at least eight other small individuals which were nicknamed "hobbits." Only some of the remains have so far been published but they are currently the most controversial fossils known to paleoanthro-pology.
These diminutive hominins stood about 3 feet tall and had brains the size of chimpanzees. The physical description may sound like an australopith, but complex stone tools were associated with them in the cave and there is evidence that they hunted pygmy elephants. Also, the site dates between 18 and 13 Kya, which is far later than any australop-iths, and the morphology of the teeth and skull resemble early Homo. So the fossils were given a new species, Homo flo-resiensis.
Reminiscent of the early assessments of Neanderthals, critics argue that the small skull (380 cc) is pathological (Figure 3.16). They posit that the hominin had a condition like microcephaly where the brain does not develop properly and remains dangerously small into adulthood. Supporters of the new species and its "normalcy" point out that microcephalics often have a misshapen cranium and face and the Liang Bua skull does not. In fact, the LB1 en-docast shows that although it was small, the H. floresiensis brain was sophisticated. Two different genes (microcephalin and ASPM) when mutated, can cause microcephaly, but unfortunately, even if researchers were able to extract ancient DNA from H. floresiensis, the chances are
Homo floresiensis (Hobbit)
Figure 3.16 A comparison between the skulls of a modern human (H. sapiens) and a so-called "hobbit" (H. floresiensis) shows how they differ in their faces and overall sizes. Illustration by Jeff Dixon.
very slim that a sequence containing either of these genes would be preserved.
Although there is only one skull so far, there are several postcranial elements that share the small body size. H. floresiensis looks like a dwarfed species of hominin, although it does not share limb proportions with living dwarfed or pygmy humans. Dwarfing is common for large-bodied animals like elephants and hippos that evolve in isolation on islands. At present, H. floresiensis is seen as a descendent of Indonesian H. erectus that got isolated on Flores 800 Kya and succumbed to the ecological pressures of island living by dwarfing its body size. Further research is needed to understand how the mammalian brain, particularly the hominin brain, reacts to island dwarfism in order to best address the microcephaly and the dwarfing hypotheses and also to determine if H. floresiensis is indeed a descendent of H. erectus.
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