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

<jats:p>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&amp;ndash;Quaternary teleost dynamics in the western Pacific. Based on 4,893 newly collected otoliths along the Dahan River section in northern Taiwan, our 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, the 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. Scaling up to a regional framework, we compiled 5,083 sciaenid otolith occurrences from the western Pacific, revealing a transition from Late Miocene endemic shelf taxa to Plio&amp;ndash;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 are currently Plio&amp;ndash;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.</jats:p>