New estimates of brain size for Homo floresiensis make it more feasible that the diminutive hominid descended from Homo erectus.

Credit: DAISUKE KUBO

The origins of H. floresiensis have been intensely debated in the decade since the roughly 18,000-year-old fossils of the 1-metre-tall hominid were discovered on the island of Flores in eastern Indonesia. Yousuke Kaifu at the University of Tokyo and his colleagues used replicas of an H. floresiensis skull and high-resolution computed-tomography scans to make models (pictured) of the hominid's brain. Their calculation of 426 cubic centimetres — roughly one-third the volume of a human brain, and the most accurate estimate so far — is slightly bigger than previous estimates. Just big enough, the authors say, that it is mechanistically possible that H. erectus underwent extreme dwarfism on an isolated island.

Proc. R. Soc. B 280, 20130338 (2013)