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The Piña assemblage, represents a rare fossil record of a mesopelagic fish-dominated ecosystem linked to coastal upwelling during the Late Miocene Reconstruction of Late Miocene mesopelagic fish-dominated ecosystem in Caribbean Panama. Artwork by Yun-Kae Kiang. in Lin et O’Dea, 2025. |
Abstract
Marine fossils from the Upper Miocene Chagres Formation in northern Panama offer critical insights into the paleoenvironmental conditions and ecological responses prior to the separation of the Atlantic from the Pacific by the formation of the Isthmus of Panama. Here we present a systematic study based on more than 6,200 otoliths collected from a coastal exposure near the town of Piña, Colón. This assemblage is remarkable for the extraordinary dominance of the family Myctophidae, constituting over 96% of specimens. The otolith density in the sediments is among the richest known globally (278.80 ± 135.59 otoliths/kg). The taxonomic composition is represented by 31 taxa across 12 families, including four new species: namely Chiloconger aflorens sp. nov., Dasyscopelus inopinatus sp. nov., Hoplostethus boyae sp. nov., and Malakichthys schwarzhansi sp. nov. Taphonomic evidence, combined with abundant predatory marine vertebrate fossils and extensive burrow ichnofossils, indicates a dynamic and highly productive nearshore ecosystem. The dominance of myctophids and multiple lines of evidence support the existence of a Late Miocene coastal upwelling system in the region, highlighted by efficient trophic transfer channeled from high primary production to apex predators. These findings provide a nuanced understanding of Neogene marine ecosystems prior to the final emergence of the Isthmus of Panama.
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| Reconstruction of Late Miocene mesopelagic fish-dominated ecosystem in Caribbean Panama. The illustration highlights key taxa, including lanternfish, hatchetfish, billfish, Isistius sharks, Otodus megalodon, Isthminia panamensis, and Lepidochelys sea turtle. Artwork by Yun-Kae Kiang. |
Chien-Hsiang Lin and Aaron O’Dea. 2025. Remarkable Dominance of myctophid otoliths in Upper Miocene Chagres Formation, Caribbean Panama. PeerJ. 13:e20155. DOI: doi.org/10.7717/peerj.20155 [October 17, 2025]
