Paleoecological Reconstruction and Chronological Framework of the Lang Trang Cave Complex, Vietnam

Sonia Reyes Hidalgo1*, Wenjing Yu1, Pierre-Olivier Antoine2, Anne-Marie Bacon3, Nicolas Bourgon4, Anh Tuan Nguyen5, John-Paul Zonneveld6, Anja M. Scheffers1, Russel L. Ciochon7, Kira Westaway8, and Renaud Joannes-Boyau1

The Lang Trang cave complex in northern Vietnam preserves one of the most extensive and taxonomically diverse Middle to Late Pleistocene faunal assemblages in mainland Southeast Asia, providing a key record for examining faunal persistence and ecological change across multiple climatic cycles. Although widely cited and used as a regional reference for faunal comparisons, the site has remained one of the few extensively studied localities in the region without a robust chronological and environmental framework. Here, we analyze fifty-three fossil teeth using δ¹³C and δ¹⁸O stable isotope analyses, trace element ratios, and combined U-series and US-ESR dating, together with optically stimulated luminescence (OSL) dating of associated sediments, to refine the temporal context and reconstruct habitat use at Lang Trang. The results indicate predominantly C₃ forest environments, with intermittent expansion of more open or edge habitats that supported distinct dietary niches and limited trophic overlap among taxa. Variability in isotopic and elemental signatures through time reflects faunal responses to monsoonal dynamics and climatic fluctuations across multiple Pleistocene phases. Newly generated U-series and US-ESR ages substantially revise the age range of the assemblage, providing improved chronological resolution and situating ecological change within a broader Middle to Late Pleistocene framework. Together, these data clarify the timing and nature of faunal community dynamics at Lang Trang and strengthen its contribution to regional paleoecological and paleontological syntheses in Southeast Asia.