The discovery of fossils of miniature humans in Indonesia, designated Homo floresiensis but nicknamed Hobbits, was one of the most exciting and controversial announcements of 2004.  Since then, interpretations of the fossils have fallen into two camps: those who think the skeletons represent normal humans with the brain-defective disease microcephaly (10/11/2006), and those who think they represent evolutionary missing links (10/25/2005).  A new paper compared skulls of H. floresiensis with those of modern humans, Homo erectus,and humans with microcephaly.  The result favors the interpretation that the Hobbits most likely were diseased modern humans.

The paper was published in PNAS today.1 Using MRI, a team of three anthropologists from New York University and Columbia University measured craniometric ratios for 21 age-corrected skulls infants with microcephaly, with 118 normal skulls for control.  In addition, they measured skull bones of 10 microcephalic individuals, 79 anatomically modern humans, and 17 Homo erectus specimens.  These were compared with two skulls of the so-called Hobbits from Ling Bua cave 1 (LB1).  The results put pressure on those who maintain that the Hobbits represent an evolutionary transitional form prior to the emergence of modern humans:

The findings showed that the calculated cerebral/cerebellar ratios of the LB1 endocast [Falk D, et al. (2007) Proc Natl Acad Sci USA 104:2513–2518] fall outside the range of living normocephalic individuals.The ratios derived from two LB1 endocasts also fall largely outside the range of modern normal human and H. erectus endocasts and within the range of microcephalic endocasts. The findings support but do not prove the contention that LB1 represents a pathological microcephalic Homo sapiens rather than a new species, (i.e., H. floresiensis).

In another paleoanthropology article on PhysOrg, we learn that diet can play a big part in the shape of human fossils.  Researchers at Johns Hopkins found that “use over time and not just genetics informs the structure of jaw bones in human populations.”  It’s all about engineering: “The changes to the jaw bones were explained using a theory drawn from engineering, which directly relates the geometry of a bone to the stresses put on it during use.”….

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