First records of two reversed flatfishes, Engyprosopon maldivense and Engyprosopon grandisquama (Actinopterygii, Pleuronectiformes, Bothidae), from Taiwan, northwestern Pacific Ocean

Two species belonging to the genus Engyprosopon in the flatfish family Bothidae, exhibiting the reversed condition not only externally but also internally, were recently collected from southwestern Taiwan. A detailed description of each specimen is provided, and situs inversus is discussed. Previously, reversed specimens in the family Bothidae were extremely rare, with only three reported cases, whereas the reversed condition was commonly found in the families Paralichthyidae and Pleuronectidae.

This rarity is possibly due to their low commercial value, which results in a low chance of detecting an inversion. Previously, it was thought that the family Bothidae was the most specialized group within the order Pleuronectiformes, making the reversed condition less likely to occur. However, this idea may need reevaluation, and the reversed condition in Bothidae may be more common than previously thought.