The embryonic development of the olfactory system in Amphiprion melanopus (Perciformes : Pomacentridae) related to the host imprinting hypothesis

Development of the olfactory system in anemonefish embryos of the species A mphiprion melanopus was examined from day six post-fertilization, until hat ching (day nine). An olfactory placode with receptor cells lining the epith elium and nerve axons from the placode into the olfactory bulb, was observe d on newly hatched embryos. In addition, two different secondary bilateral receptor systems were found. These findings may firstly support the anemone fish host imprinting hypothesis, and secondly indicate that the ontogenetic timing of this imprinting mechanism occurs towards the end of the embryoni c development.