Gradual teleost modernization in the western Pacific: Neogene-Quaternary otolith evidence

Otolith paleontology traditionally relies on descriptive alpha taxonomy and standard ecological inference, leaving some aspects of long-term community restructuring insufficiently explored. Here we apply a quantitative community framework integrating formal beta diversity partitioning, which separates species turnover from nestedness, and multivariate dispersion analyses to evaluate Neogene–Quaternary teleost dynamics in the western Pacific. Based on 4,893 newly collected otoliths along the Dahan River section in northern Taiwan, the dataset completes an 8-million-year sequence extending from the Late Miocene into the Quaternary. Multivariate analyses resolve three distinct, epoch-defined assemblages: Miocene, Pliocene, and Pleistocene. Moreover, otolith-based community restructuring across temporal transitions was driven by taxonomic turnover that suggests gradual faunal replacement rather than simple diversity loss or nestedness-driven assemblage contraction. At the regional scale, we compiled 5,083 sciaenid otolith occurrences from the western Pacific, revealing a transition from Late Miocene endemic shelf taxa to Plio–Pleistocene assemblages increasingly dominated by extant lineages. Finally, this sciaenid otolith record exposes discrepancies with molecular-clock hypotheses that infer older divergence times for several modern lineages whose fossil appearances currently date to the Plio–Pleistocene. Our study demonstrates how fossil otoliths can be used to link local paleoecological signals with regional community turnover, providing empirical constraints for molecular phylogenies and contributing to a better-resolved view of teleost evolution in the western Pacific.