Abstract:In this study, Salmacis sphaeroides variegata was used as the research material to observe its morphology. Based on mitochondrial 16S rDNA gene partial sequencing, the genetic relationship between S. sphaeroides variegata and other echinoderms was analyzed. The nutritional composition of S. sphaeroides variegata gonad was analyzed to accumulate a mass of data for germplasm improvement and resource evaluation of S. sphaeroides variegata. The results showed that the main morphological characteristics of the S. sphaeroides variegata were as follows: the apical system was small, the outer edge of each step band plate had 3~4 small circular pits, and the bone fragment in the wall of the pedicle foot was C-shaped. The mitochondrial 16S rDNA gene sequences of other echinoderms and that obtained from S. sphaeroides variegata were compared by Mega 5.0, and the phylogenetic trees were constructed based on distance method (NJ) and maximum likelihood method (MP). The results showed that the S. sphaeroides variegata was closely related to the Salmacis bicolor, followed by the three species of sea urchins, the Temnopleuridae. An amount of water 86.1%, ash 3.0%, crude fat 2.0% and protein 8.01% was found in the sex glands of S. sphaeroides variegata. There were 16 kinds of amino acids in the sex glands of S. sphaeroides variegata, the total amino acid content was 38.71 g/100 g, EAA/TAA was 36.99%, EAA/NEAA was 71.84%, and DAA/TAA was 37.17%. A total of 15 fatty acids were detected, with the highest content being palmitic acid C16:0, stearic acid C18:0, EPA C20:5 and arachidonic acid C20:4, and the lowest content was that of C20:3. S. sphaeroides variegata showed a higher content of DHA than in other sea urchins. The results will provide basic data for the biological study of S. sphaeroides variegata and can be used for the development and application of sea urchin of economic value, as well as provide a theoretical basis for distant hybridization breeding and the germplasm identification of economically viable sea urchins.
