Abstract: The morphological features of the Lantian skull found in Gongwangling, Lantian, in 1964, is more primitive than the Homo erectus fossils from Zhoukoudian and Java, Indonesia. The extraordinary thickness of the cranial wall and the rather small cranial capacity make Lantian fall into the variation range of early Homo. The newly dated Lantian fossil to ca. 1.63 Ma BP, close to the lower limit of Homo habilis and Australopithecus variation range is significantly older than the previously supposed date of 1.15 Ma BP. This new date now makes the Lantian the earliest fossil hominin in China. In this paper, we extracted and reconstructed the three-dimensional bony labyrinth image of Lantian’s petrous part of the temporal bone using high-resolution computed tomography (CT) technology. Comparison of this area with the Hexian Homo erectus, four Middle European Pleistocene archaic Homo, four early Homo, four Australopithecus africanus, three Paranthropus robustus and 26 modern humans using 21 measurement variables gives the following results. Measurements of the Lantian labyrinth have most in common with Australopithecus africanus, followed by modern humans and the Middle Pleistocene archaic Homo group. The Lantian specimen differs mostly with early Homo and Paranthropus robustus. According to the results of principal component analysis, the Lantian labyrinth overlaps with those of early Homo, the Middle Pleistocene archaic Homo group, Australopithecus africanus and modern humans. By cluster analysis, the nearest specimen to Lantian is Australopithecus Sts 5, followed by the Hexian Homo erectus and Australopithecus Sts 19, and far away from Paranthropus robustus. This study provides new data on the bony labyrinthine morphology of Middle Pleistocene Chinese human fossils, and supplies new references for exploring the Lantian physical features.

Key words: Lantian; Homo erectus; Labyrinth; Middle Pleistocene; Australopithecus; 3D reconstruction