Neurocranial abnormalities of the Gongwangling Homo erectus from Lantian,China

The Homo erectus cranium found at Gongwangling, near Lantian, China, and dated to ≈1.2 ma BP has been analyzed with respect to its evolutionary position. However, the remains, and especially the internal and external surfaces of the neurocranium, present a series of marked abnormalities. These irregularities consist principally of a pronounced cresting and scalloping of the external surface of the frontal bone and anterior parietal bone and a similar alteration of the internal surface of a mid transverse section of parietal bone that connects with the fossilization break across the anterior parietal bone. There is no obvious exposure of diploë on the surfaces. Woo (Vertebrata PalAsiatica 10:1–16, 1966) briefly ascribed these abnormalities to postmortem erosion, and Caspari (Am. J. Phys. Anthropol. 102:565–568, 1997) has attributed the irregularities of the right supraorbital torus to antemortem trauma. It has been suggested that the pervasive neurocranial alterations might be pathological. Computerized tomography (CT) analysis of the frontal and parietal bones revealed complete radiopacity of the anterior half of the fossil; it is possible to distinguish large frontal sinuses but other details, including in the area of the purported traumatic lesion, are invisible. However, in the posterior frontal bone and preserved portions of the parietal bone the diploë and tables are discernible. Externally on the frontoparietal section and internally on the transverse parietal piece, there are clear erosional lacunae in the associated table, combined with a thin layer of matrix which obscures the eroded diploë externally. The superficial irregularities are therefore due to postmortem taphonomic alterations of the bone and not pathological processes. In addition, it is apparent that the two pieces were embedded in the matrix at different angles, resulting in their differential erosion.