The classification of gobioid fishes is still under discussion. Several lineages, including the Eleotridae and Butidae, remain difficult to characterize because synapomorphies are rare (Eleotridae) or have not yet been determined (Butidae). Moreover, the fossil record of these groups is scarce. Results Exceptionally well-preserved fish fossils with otoliths in situ from uppermost Oligocene sediments (≈23–24 […]