The embryological and larval development of the sea urchin Diadema savignyi (Audouin, 1809) (Diadematoida: Diadematidae) from the South China Sea

Abstract

ABSTRACTThis paper provides the first descriptions of embryonic and larval development of the sea urchin Diadema savignyi (Audouin, 1809) (Diadematoida: Diadematidae). Diadema savignyi developed from relatively small eggs, 79.24 ± 6.37 µm. At 26–27°C, the embryonic development of D. savignyi took about 7 h until hatching from the fertilization envelope at the blastula stage and beginning of the larval life. Then the larvae went through the following stages of development: spherical blastula (7–12 h), gastrula and prism (23–31 h), pluteus with one pair of larval arms (48 h), pluteus with two pairs of larval arms (50–72 h), and late pluteus (14–18 d). In the late stages of larval development, the proportions of the larval body change greatly. The duration of development of D. savignyi from fertilization to the juvenile stage was 45–47 days. The larval development of D. savignyi and other species having the Echinopluteus transversus type of larvae, whose development was studied earlier, is reviewed and described on the basis of own data and those published previously in literature in order to compare the development of plutei within the family Diadematidae.