Fish ear bones help identify elusive Killifish species

Charmpila E. A., Teimori A., & Reichenbacher B. (2024). Otolith-based species identification in the killifish Aphaniops (Teleostei; Cyprinodontiformes; Aphaniidae) using both morphometry and wavelet analysis. Acta Zoologica, 00, 1–18. https://doi.org/10.1111/azo.12518

The authors have found that the shape of tiny ear bones—called otoliths—can help distinguish between closely related species of Aphaniops killifish. Using advanced shape analysis and measurements from nearly 90 specimens, the study shows that most species can be identified based on differences in specific parts of the otolith. One method, called morphometry, proved especially useful, while a newer wavelet-based method had trouble telling apart some similar species. The study also found that certain species show high variability, likely due to environmental factors or possible interbreeding. These results highlight otoliths as a powerful tool for identifying fish species and understanding their evolutionary history, especially when external features are too similar to tell them apart.