Egg morphology, larval development and description of the oncomiracidium of Heterobothrium ecuadori (Monogenea: Diclidophoridae) parasitising the bullseye pufferfish, Sphoeroides annulatus

The present study is the first description of the egg morphology, embryonic development, and time required for hatching, and longevity of the oncomiracidium of Heterobothrium ecuadori (Meserve, 1938) Sproston, 1946. Experiments found that hatching time fluctuated between 7 and 10 days with a mean of 7.5 ± 1 days at 23 ± 1° C and 35 ‰. Eggs were provided with a polar filamentous appendage. The body of the oncomiracidium was flattened dorso-ventrally, 156 ± 9 μm long and 65 ± 8 μm wide. A full description of the egg development and morphology of the oncomiracidium is provided. The longevity of the oncomiracidia was 4–7 days at 21 ± 1°C, with a mean survival time of 121.8h. The ability to rear diclidophorids like H. ecuadori and to record precise information on their development provides valuable data for further studies.