LOWER PLIOCENE FISH OTOLITHS FROM THE CABARRUYAN ISLAND, NORTHERN PHILIPPINES

作者：Dominique Mediodia, LORRIE ANNE TORRALBA, John Phillip Baguio, LEOPOLDO DE SILVA, ALLAN GIL FERNANDO, Chien‐Hsiang Lin · 发表于：RIVISTA ITALIANA DI PALEONTOLOGIA E STRATIGRAFIA · 年份：2026 · DOI：10.54103/2039-4942/30891 · 研究领域：Geological and Geophysical Studies、Geological formations and processes、Coral and Marine Ecosystems Studies

Fish otoliths are commonly found in the fossil record and are crucial for reconstructing past environments, especially in areas such as the Philippines, where well-preserved fish fossils are rare. This study analyzed fish otoliths from the Lower Pliocene clastic unit in Cabarruyan Island, northwestern Luzon Island, Philippines. The age of the sediments was constrained using calcareous nannofossil biostratigraphy, based on the last occurrence (LO) of Reticulofenestra pseudoumbilicus (Gartner, 1967) Gartner, 1969 and the first occurrence (FO) of Pseudoemiliania lacunosa Kamptner, 1963 ex Gartner, 1969. Bulk sediments were screen-washed, and individual otoliths were separated and identified. A total of 1,225 fish otoliths were analyzed, revealing 69 taxa in 28 families. We also report two new species: Benthosema rarang sp. nov. and Myctophum luzonicum sp. nov., as well as new fossil otolith records from the Philippines. The fish assemblage was dominated by the families Myctophidae, Sternoptychidae, Bregmacerotidae, Macrouridae, and Gobiidae, which agrees with findings from a previous study. The dominance of these families indicates an open marine environment and a tropical-to-subtropical climate during the Pliocene. The co-occurrence of deep- and shallow-water taxa in our study, together with other recorded fossils (e.g., fish vertebrae and scales, sea urchins, brachiopods, and other mollusks), suggests an outer-shelf-to-upper-slope paleoenvironment. This study not only provides...