Introduction Material Results Methods Conclusion Virtual reconstruction of the Ouranopithecus macedoniensis cranium (Miocene, Central Macedonia, Greece) Melania Ioannidou1, George Koufos2, Louis de Bonis3, and Katerina Harvati1 1 Eberhard-Karls University of Tübingen. Paleoanthropology, Institute for Archeological Sciences, Senckenberg Center for Human Evolution and Paleoecology, Rümelinstraße 23, Tübingen 72070, Germany 2 Aristotle University of Thessaloniki. School of Geology, Laboratory of Geology & Paleontology, GR-54124 Thessaloniki, Greece 3Université des Poitiers. Institut International de Paléoprimatologie, Paléontologie Humaine et Paléoenviroments (IPHEP)-UMR7262, Poitiers, France The aim of this study is to virtually restore symmetry to the deformed face of Ouranopithecus macedoniensis (XIR-1) and to reconstruct its facial anatomy using mirror imaging, a virtual anthropology technique. The most important advantage of such methods, relative to traditional reconstruction techniques, is that they allow digital manipulation of the objects and therefore are not destructive or damaging the precious fossil specimens. Introduction The genus Ouranopithecus has been documented since 1974 in the late Miocene deposits of Northern Greece in the form of several mandibles, a number of teeth and an almost complete face (XIR-1) of Ouranopithecus macedoniensis. The specimen XIR-1 belongs to an adult male individual and was discovered in 1989 in the locality Xirochori 1 (XIR). The magnetostratigraphic study of the Xirochori section suggested an estimated age of ~ 9.6 Ma (late Vallesian,) for the fauna. The facial area of the XIR-1 is well preserved, but slightly distorted as a result of taphonomic processes. The right side of the lower face is complete, and a big portion of the frontal bone as well as part of the left side of the face is preserved. Mirror surface edit (a and b) and the result (c). Material O. macedoniensis (XIR-1): face and maxilla with an almost complete dentition. Photographs by G. D. Koufos. Results Methods The XIR-1 cranium was scanned with a high resolution microCT scanner, in the University of Tübingen (Phoenix X-Ray, v/tome/x s GE, Paleoanthropology High Resolution Computed Tomography Laboratory, University of Tübingen). The virtual reconstruction of the XIR-1 cranium involves mirror imaging of the right anatomical side to the left, followed by 3D editing of the surfaces (original and mirror). The virtual reconstruction was carried out using the AVIZO software (© FEI Visualization Sciences Group, Version 7.1). The final result of the reconstruction of XIR-1 cranium after merge in (a) frontal, (b) occipital, (c) right lateral, (d) left lateral, (e) basal view, and (f) superior view. Conclusion This preliminary facial virtual reconstruction of the partly deformed XIR-1 cranium, was achieved using mirror imaging of the better preserved anatomical side to reconstruct the other. This reconstruction composes the first attempt of correcting the symmetry of the O. macedoniensis cranium. Additional analyses, using 3D geometric morphometrics, will explore phylogenetic relationships between O. macedoniensis, other fossil hominoids, and extant great apes. Selected references de Bonis, L., et al., 1990. New hominid skull material from the late Miocene of Macedonia in Northern Greece. Nature, 345(6277), pp.712-714. Gunz, P., etal., 2009. Principles for the virtual reconstruction of hominin crania. Journal of Human Evolution, 57(1), pp.48-62. Acknowledgments Dr. Hugo Reyes-Centeno, Dr. Catherine Bauer, Dr. Heike Scherf, Wieland Binczik and the Paleoanthropology team at INA. Also, DAAD for financial support.