STONY BROOK (US) — Detailed analysis of a small skull found in Indonesia in 2003 suggests Homo floresiensis represents a distinct Homo species.
Researchers say it’s not likely that the skull (called Liang Bua 1 or LB1) belonged to a modern human with a disorder, such as microcephaly, that resulted in an abnormally small brain and skull.
Healthy modern humans (top left); modern humans with microcephaly (bottom left); LB1 (Homo floresiensis) (top right, shown in purple); and fossil humans belonging to the genus Homo (bottom right). These images highlight how much taller and rounder the modern human braincase is compared to the other three groups when viewed from the side. (Credit: Stony Brook University)
The scientists applied the powerful methods of 3D geometric morphometrics to compare the shape of the LB1 cranium (the skull minus the lower jaw) to many fossil humans, as well as a large sample of modern human crania suffering from microcephaly and other pathological conditions. The analysis was conducted by scientists from Stony Brook University, the Senckenberg Center for Human Evolution and Palaeoenvironment, Eberhard-Karls Universität Tübingen, and the University of Minnesota.
Geometric morphometrics methods use 3D coordinates of cranial surface anatomical landmarks, computer imaging, and statistics to achieve a detailed analysis of shape.
The study, published in PLOS ONE, is the most comprehensive to date to simultaneously evaluate the two competing hypotheses about the status of Homo floresiensis.
The study found that the LB1 cranium shows greater affinities to the fossil human sample than it does to pathological modern humans.
Although some superficial similarities were found between fossil, LB1, and pathological modern human crania, additional features linked LB1exclusively with fossil Homo. The team could therefore refute the hypothesis of pathology.
Source: Stony Brook University