The Kocabaş fossil hominin consists of a fragmentary skull made up of three fragments: a right part of the frontal bone including the lateral part of the supraorbital torus, a lateral part of the left part of the frontal bone still in connection with a small piece of the left parietal, and a rather similar fragment of the right parietal bone. It was discovered in 2002 in the Denizli Basin (S-W Turkey) during quarrying activities. Attributed to Homo erectus in the first description (Kappelman et al., 2008), this assumption was confirmed by the studies that we have been carrying out for over 10 years (Vialet et al., 2012, 2014, 2018). In their article, Mori et al. (2024) described a new reconstruction of this fossil and detailed three-dimensional geometric morphometric analyses.

We were interested in their results which are, in some respects, not far from the ones we published previously. In contrast, it is in the interpretation of these results that we differ markedly. Mori et al. have shown that the Kocabaş fossil has a short frontal bone and significant development of its supraorbital torus. While they describe these features as intermediate between the H. erectus s. l. and Middle Pleistocene Homo, they concluded that Kocabaş “may be an early representative of the same taxonomic unit to which Bodo, Broken-Hill 1/Kabwe, and Ceprano belong” (Mori et al., 2024: 12). Based on the same morphological observations, we did not make a connection between Kocabaş and these specimens, but rather with H. erectus s. l. (Vialet et al., 2012, 2014) and more specifically with African forms, in particular fossils such as Bouri (Daka) and Buia dated to around 1 Ma (Vialet et al., 2018).

In addition, we would like to address an important point highlighted by Mori et al. namely the dating of this fossil. Based on the work we have been carrying out for over 10 years in the field, combining different dating methods and studying in detail the animal fossils associated with the hominin skull, we consider that our previous chronological attribution of this specimen to the Lower Pleistocene is accurate and we confirm that it securely belongs to the Lower Pleistocene.