Abstract This study reports a three-dimensional fossil skull of a Tetraodontidae that dates to the middle Miocene (Serravallian), which was recovered from a rock matrix from the Valiente Peninsula Formation in the Bocas del Toro Archipelago, Caribbean coast of Panama. The new species, †Lagocephalus striatus n. sp., is the first fossil species of Tetraodontidae described from the Proto-Caribbean/Central Western Atlantic. We used high-resolution micro-CT scans of fossil and extant species to identify morphological characters on the skull, including the neurocranium, oromandibular and opercular bones, hyoid arch, and pectoral girdle. Specimens of both extant and extinct species of similar size were compared for accurate identification. We assess the paleogeographic distribution of the pufferfish group in the Neogene of Tropical America after the complete formation of the Isthmus of Panama.