Omani Killifish Shows Surprising Diversity

Bidaye R. G., Al-Jufaili S. M., Charmpila E. A., Jawad L., Vukić J., & Reichenbacher B. (2023). Possible links between phenotypic variability, habitats and connectivity in the killifish Aphaniops stoliczkanus in Northeast Oman. Acta Zoologica, 104, 262–278. https://doi.org/10.1111/azo.12428

In this study on the freshwater killifish Aphaniops stoliczkanus from northern Oman reveals surprising variation in body shape, coloration, and ear bone (otolith) structure across different habitats. Scientists found that fish from a hot sulphuric spring had a unique otolith shape, hinting at the possible presence of a hidden, or “cryptic,” lineage. This suggests that environmental factors like temperature and water chemistry may drive physical changes within the species. The findings offer new insights into how freshwater fish adapt and evolve, and highlight the importance of studying these differences to better understand fish diversity. The results may also help researchers interpret fossil fish, where only shape and structure can reveal evolutionary relationships.