3D CT Scan Shows Brain Morphology of Homo Liujiang Cranium Fossil

High-resolution industrial computed tomography (CT) imaging is being used to scan a Homo Liujiang cranium fossil, and a three-dimensional (3D) virtual brain image was reconstructed from the technology. More information for the phyletic evaluation of the Homo Liujiang was derived from this new research.

Hominin fossils are the most important components to study human origins and evolution. Since most hominin fossils are incomplete, or filled with a heavy calcified matrix, it is difficult or frequently impossible to reconstruct the endocast in a real fossil without destroying it. Consequently, conventional techniques limited the study of human brain evolution.

CT can examine fossils in a noninvasive way by converting a real into a virtual object, and make it possible for paleoanthropologists to extend the study of fossil specimens from the exterior to the interior. Using high-resolution industrial CT, the Homo Liujiang brain image was reconstructed.

The Liujiang cranium is the most complete and well-preserved late Pleistocene human fossils ever unearthed in South China. Because the endocranial cavity is filled with hard stone matrix, earlier research focused only on the exterior morphology of the specimen using the traditional methods. Arguments about the phyletic evaluation of the Liujiang hominin fossil have existed for a long time.

The new research was led by Dr. Wu Xiujie, from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP; Beijing, China). In this study, the investigators utilized high-resolution industrial CT to scan the Liujiang cranium, and reconstruct the 3D brain image. Compared with the endocasts of the hominin fossils and modern Chinese, most morphologic features of the Liujiang brain are in common with modern humans, including a round brain shape, bulged and wide frontal lobes, an enlarged brain height, a full orbital margin, and long parietal lobes.

There are a few differences between Liujiang and the modern Chinese in the Chinese researchers' sample, including a strong posterior projection of the occipital lobes, and a reduced cerebellar lobe. The measurement of the virtual endocast showed that the endocranial capacity of Liujiang is 1567 cc, which is in the range of Late Homo sapiens and much beyond the mean of modern humans. The brain morphology of Liujiang is assigned to Late Homo sapiens.

IVPP is the only institute chiefly dealing with the research of origin and evolutionary history of hominin fossils. In the past 80 years, a few complete hominin crania fossila were found in China. "With CT scanning and 3D visualization techniques to reconstruct virtual specimens, it is now possible for Chinese hominin paleontologists to conduct paleoneurological studies of our national treasures,” said Dr. Wu Xiujie.

The study was published in the August 2008 issue of the Chinese Science Bulletin.

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Institute of Vertebrate Paleontology and Paleoanthropology