Infant craniofacial diversity in Early Pleistocene Homo

The adult craniofacial diversity of early Pleistocene Homo species is relatively well-documented, but its developmental foundations is hindered by the scarcity of infant specimens with preserved skeletal features. Here, we present evidence of craniofacial development in early Pleistocene Homo infants. This study focuses on a mandible (Omo 222-1973-2744) from the Lower Omo Valley in Ethiopia, attributed to Homo habilis, along with a mandible (KW 7000) from Kromdraai and a maxilla (DNH 83) from Drimolen, both in South Africa. We find that early Homo from southern Africa includes infant specimens with diagnostic facial features, with DNH 83 and KW 7000 uniquely combining both dental and skeletal evidence. Structural differences between the mandibles of Omo 222-1973-2744 and KW 7000 attributed to Homo aff. H. erectus, suggest that taxonomic diversity in early Homo was already evident in infancy. Furthermore, the unique combination of mandibular and dental features in these infants highlights the importance of integrating both dental and cranial morphology to identify early Homo.