A primeira ocorrência do atum Thunnus sp. (Família Scombridae) no registo fóssil Miocénico de Portugal

ABSTRACT: The fossil record of tunas (tribe Thunnini, family Scombridae) is sparse due to their pelagic lifestyle. Yet such finds are essential for reconstructing evolutionary and biogeographic patterns of these marine apex predators. We report the first occurrence of Thunnus sp. in Portugal, based on a well-preserved caudal vertebra from Burdigalian (Lower Miocene) deposits at Praia da Foz da Fonte (Baixo Tejo Basin, Setúbal Peninsula). The specimen, although recovered ex situ, is confidently attributed to the Lower Miocene shallow-marine succession of the locality. Morphological features—including an amphicoelous centrum, paired lateral foramina, and distinct growth rings—support its assignment to a large scombrid, consistent with the taxon Thunnus. Estimated body length exceeds 284 cm, indicating the presence of large pelagic predators from this genus in Miocene seas of western Iberia. This find represents the earliest tuna record from Portugal and supports a widespread Miocene distribution and diversification of the genus Thunnus across Europe and the Americas.