Does the divided infraorbital foramen diagnose the Asian lion?
Two lions from Iran have DIF (Appendix 1), contradicting the hypothesis that DIF distinguishes the skulls of Indian lions from Gujarat, from not only those of all other lions, including other Asian lions, but also from those of all other felids (O’Brien et al., 1987). Although our results show that DIF is not exclusive to the Gir Forest lions, it can be confidently reported that DIF rarely appears in sub-Saharan African lions, which, on the basis of a molecular phylogeny, are likely to be ancestral to the North African -Asian population (Barnett et al., 2006a). Also, our results suggest that the extinct North African Barbary lion does not seem to have DIF, at least at a high frequency. Furthermore, it is suggested based on maternally inherited mitochondrial DNA, that the modern lion does not appear to have hybridised with the extinct northern Holarctic lions of the Pleistocene, including the European cave lion (Burger et al., 2004; Barnett et al., 2009), where 13% have DIF. Therefore, a higher DIF frequency in the Asian population may be a characteristic that developed after the lion colonised Asia, potentially reflecting the recent colonisation history of the lion. These arguments suggest that the higher frequency of DIF in Asian lions is still an important morphological feature that distinguishes their skulls from those of African lions, even though we now know that some African individuals have it.