Comparative Study of the Spine of Echinometra in Palau, Okinawa and Kagoshima

Development of Marine Biological Resources and Conservation of the Marine EnvironmentFour types of the sea urchin genus Echinometra are seen on the coast of Okinawa islands, south-western Japan and recently they have been treated as four different species (A, B, C & D) based on chromosome studies and spicule characteristics. In this study, species distribution of Echinometra in Palau and Kagoshima (southern Kyushu, Japan) was studied. We could collect three species, A, B and C, in Palau and four species in Kagoshima. Ultrastructural study of the surface of the spine of species A, B and C, from Palau, Okinawa and Kagoshima was carried out to clarify the geographic variants among them. It might be concluded that the three species of Ehinometra in Palau have almost equal characteristics to the Okinawan species. However, species A and C in Kagoshima have some peculiar characteristics. It is suggested that geographic variants among intraspecific specimens are going to occur in sea urchins in Kagoshima