Ten years ago, a team of Australian and Indonesian researchers discovered what one scientist described as "the most important find in human evolution for 100 years." They found the approximately 15,000-year-old remains of ancient humans—including one skull—in a cave on Indonesia's Flores island. The remains, they concluded, belonged to a distinct species of Homo, whose notably tiny size soon earned it the nickname the Flores hobbit.
As The New York Times writes, those findings, however, were almost immediately subject to debate. Some thought that a single skull was too little evidence to base an entire species on, while others questioned that the skull's small size might be the result of a disease rather than a unique species.
Now, the debate has reignited with two new papers published this week by a team of researchers from Penn State and other institutions. In one of those papers, they argue that the Flores skull is not a new species, but instead represents an ancient person with Down syndrome.
The researchers also point out, in the second paper, that the original report on the bones seemed to have exaggerated the skull's diminutive size. Cranial measurements and features, along with shorter thigh bones, the team found, all correspond with modern manifestations of Down syndrome. "The difference is significant, and the revised figure falls in the range predicted for a modern human with Down syndrome from the same geographic region," they say in a statement.
Additionally, the skeleton belonged to someone who stood a bit over four feet tall—the same as some modern humans in Flores. Although some researchers are resisting the "sick hobbit hypothesis," as they described it to The New York Times, the authors of the new paper insist that the existing evidence "points rather clearly to Down syndrome.”