Detalhes do Documento

Now limited to Africa, hippopotamids once represented a common element of the European megafauna. However, the ecological and phenotypic diversity of European hippopotamuses is still not fully understood. Within this fragmented framework, a mandible discovered in lacustrine deposits near Ortona (Abruzzo, Italy) provides an opportunity to better understand the morphological and morphometric diversity of European hippopotamuses. A comprehensive review of Pleistocene specimens from Central and Western Europe enables a reassessment of phenotypic variability in hippopotamuses, suggesting potential cranial trends among the late representatives of Hippopotamus antiquus. Unlike the pre-Jaramillo (ca. 1 Ma) mandibles of H. antiquus, the Middle Pleistocene ones are characterized by a lower slenderness index (SI), indicating a trend toward a more slender mandibular structure. Among these late representatives, the cranial remains from Maglianella and Ortona (Italy) suggest that specimens from these two localities were characterized by more elevated orbits, a shorter and more pronounced sagittal crest, a reduced post-orbital area, and prominent condyles, while their mandibles show a slender mandibular corpus and peculiarly small second lower incisors. This research also documents a significant sexual dimorphism observed between male and female specimens of the same species. Consequently, to accurately assess cranial variability in hippopotamids, it is crucial to also consider the effects of sexual selection. Finally, dental microwear analysis reveals a possible dietary shift between early and derived H. antiquus populations: while the early form appears to have fed mainly on soft, aquatic plants, the derived form likely consumed a diet richer in herbaceous vegetation.