Krapina and Saccopastore: Endocranial morphology in the pre-Würmian Europeans

The skulls of Saccopastore 1, Krapina 3, and Krapina 6, are sufficiently well preserved to allow the reconstruction of their endocranial casts. In addition, these specimens are useful to investigate the paleoneurological changes that occurred during the Mid-to-Late Pleistocene in Europe. The main features of their endocasts are described in this paper, and combined with some comparative metrics performed on the major endocranial diameters. The raw endocranial lengths and arcs characterize the specimens according to their general size, reflecting a generalized brain enlargement. Saccopastore 1 and Krapina 3 are rather similar for their raw diameters, and for showing a similar posterior dominance of the middle menigeal network. In contrast, Krapina 6 shows values that are more comparable with the Neanderthal range, and a more developed anterior ramus of the middle meningeal vessels. All the three specimens have the maximum endocranial width positioned over the temporal lobes, but no data are available for the general parietal development of the Krapina fossils. Because of the marked allometric component of the endocranial development in non-modern human taxa, and because of the limited preservation status of the Croatian specimens, the hypothesis of a gradual allometric variation from Middle to Upper Pleistocene in Europe (that is, between Homo heidelbergensis and Neanderthals) cannot be falsified by the present data. Future investigations should consider traits like the widening of the frontal lobes or the lateral development of the parietal surfaces to test the possibility of a more discrete transition after the Oxygen Isotopic Stage 6 in Europe.