Homo floresiensis likely represents a distinct Homo species after all, according to a new report published in the journal PLOS One.
Ever since the discovery of the remains in 2003, scientists have debated whether they represent a separate species, possibly originating from a dwarfed island Homo erectus population, or whether they represent a pathological modern human. The small size of its brain, many argued, was possibly the result of a number of diseases, most importantly from the condition known as microcephaly, a rare neurological condition that results in an abnormally small head size.
To come to a more informed conclusion, a team of scientists applied the powerful methods of three-dimensional geometric morphometrics to compare the shape of the speciman's cranium to a number of fossils, including a large sample of modern human crania suffering from microcephaly and other pathological conditions.
Geometric morphometrics methods use 3D coordinates of cranial surface anatomical landmarks, computer imaging and statistics to create a detailed analysis of shape.
In using them, the team was carrying out the most comprehensive study to date to simultaneously evaluate the two competing hypotheses about the status of Homo floresiensis.
In the end, the researchers found that the cranium under examination showed greater affinities to the fossil human sample than it does to pathological modern humans.
"Our findings provide the most comprehensive evidence to date linking the Homo floresiensis skull with extinct fossil human species rather than with pathological modern humans," the scientists stated, according to a press release. "Our study therefore refutes the hypothesis that this specimen represents a modern human with a pathological condition, such as microcephaly."
Entitled "Homo floresiensis contextualized: a geometric morphometric comparative analysis of fossil and pathological human samples," the paper was authored by researchers from Stony Brook University, the Senckenberg Center for Human Evolution and Palaeoenvironment, Eberhard-Karls Universität Tübingen and the University of Minnesota.