Estimating Endocranial Volume of Incomplete Crania Using Human Dataset
Madi Boone ’21, Marisa Petticord ’21, and Zachary Cofran (Anthropology)
Brain size and development are hallmarks of human evolution. In order to gain further insight into how human ancestors developed neurologically, our team employed state of the art methods to reconstruct and analyze incomplete Neandertal crania from the Krapina site in Croatia. We reconstructed five Krapina crania and estimated their endocranial volumes, which is used as a measure of brain size. In order to estimate the endocranial volumes, we created endocasts, which are the imprints of neural matter on the inside of the cranium. The crania were reconstructed by applying a human-based template of 441 landmarks describing the shape of the endocast. The landmarks were applied to the incomplete crania using Viewbox 4, with missing data estimated using special algorithms in R software. We then mathematically warped complete human endocasts to the Krapina landmark configurations to reconstruct their endocranial size and shape. To validate the method we also reconstructed SPY II, a later Neandertal, which is more complete than the Krapina remains. Our SPY II reconstructions were virtually identical to previous estimates using the same methods, lending confidence to our other reconstructions. Our endocranial volume estimates for Krapina 3 and 5 are consistent with previous literature with average volumes of 1249 and 1424 cm3, respectively. Krapina 6 resulted in an estimate that was smaller than previous studies (1158 cm3), and Krapina 1 reconstruction resulted in an estimate that was larger than previously thought (1417 cm3). We also created estimates for Krapina 2 (1291 cm3), which had previously not been reconstructed for endocranial volume. Our results provide revised or new data for future studies of brain evolution.