Embryonic and Postembryonic Development of Percocypris pingi pingi （Tchang）

This study aimed to investigate the morphological characteristics of Percocypris pingi pingi( Tchang) at the embryonic and postembryonic developmental periods and to demonstrate the early developmental stage of P. pingi pingi( Tchang). According to the results,the fully mature eggs were spherical,orange-colored,sticky,2. 2 mm in diameter; the maximum outer diameter reached 3. 2- 3. 8 mm after absorbing water. When water temperature was( 18 ± 0. 5) ℃,the first cleavage occurred at 2h 28 min post-fertilization; organs began to form at 45 h 23 min post-fertilization; larvae were hatched at 126 h 28 min post-fertilization.Newly hatched larvae exhibited a total length of 10. 4 mm,with large and compressed yolk sacs. According to the morphological characteristics,the embryonic developmental process of P. pingi pingi( Tchang) could be divided into seven continuous stages,including fertilized egg stage,cleavage stage,blastula stage,early gastrula stage,neurula stage,organ formation stage and hatching stage,which were further divided into 32 phases. When water temperature ranged from 18. 8 ℃to 25. 0 ℃,the whole developmental process of P. pingi pingi( Tchang) from larvae to juveniles lasted 93 d. According to the morphological and ecological characteristics,the postembryonic developmental process of P. pingi pingi( Tchang) could be divided into three stages,including yolk-sac larva stage,late larva stage and junenile stage.