A Reappraisal of the Frontal Bone and Mandibles of Late Pleistocene Hominins From <scp>M</scp> aludong, Southwestern <scp>C</scp> hina: A <scp>3D</scp> Geometric Morphometric Perspective

OBJECTIVES: Multiple Late Pleistocene hominin fossils have been discovered at Maludong, southwestern China, which exhibit a mosaic of archaic and modern human traits, revealing high hominin diversity. To further investigate the regional variation of hominins during the Late Pleistocene in East Asia, this study presents a 3D geometric morphometric analysis of the Maludong frontal bone and mandibles. METHODS: CT-scanned 3D models of Maludong frontal bone (MLDG 1704) and mandibular (MLDG 1679/1706) fossils were analyzed using 3D geometric morphometrics, alongside comparative 3D models of Pleistocene hominins and fossil/extant modern humans. RESULTS: The Maludong frontal bone and mandibular shape variation (MLDG 1706) fall within the range of variation observed in Late Pleistocene Homo sapiens and modern humans, exhibiting distinct modern human-like traits. Specifically, the frontal bone shows a reduced supraorbital ridge and a broad, globular frontal squama with greater curvature. The mandible displays a more vertical symphysis and a more elongated ramus. However, the MLDG 1679 mandible falls within the morphological range of Late Pleistocene Homo sapiens and Neanderthals, characterized by a shorter and more robust ramus. DISCUSSION: These findings indicate that the Maludong hominins share biological affinity with Homo sapiens, potentially reflecting broader evolutionary trends in modern human morphology. Meanwhile, the robusticity observed in these and other Late Pleistocene East Asian fossils highlights the wide regional craniomandibular diversity of East Asian hominins during the Late Pleistocene. This study thereby contributes to a more comprehensive understanding of the morphological diversification and the complex evolutionary history of Late Pleistocene hominins in East Asia.