CHARACTERISTICS OF EARLY DEVELOPMENT OF PTYCHOBARBUS DIPOGON IN XIZANG AUTONOMOUS REGION

This study provided technical support for its scientific protection and rational development through exploring the embryonic and larval development characteristics of Ptychobarbus dipogon. The result indicated that the egg diameter reached 3.7—3.9 mm, and egg diameter after water absorbed could reach to 5.1—5.3 mm. The hatching of egg taken 336.02 hours at temperature of 10℃. Based on external morphological characteristics, embryonic development were separated into 7 stages and 34 periods, including cleavage preparing stage, cleavage stage, blastula stage, gastrula stage, neural embryo stage, organ differentiation stage and hatching stage. Characteristics included newly hatching fry with body length of 12.4 mm, 1 day fry after hatching with pectoral fin upwarp, operculum, pigment and underjaw primordial appearance, 3 day fry after hatching with hepatopancreas primordial and alimentary canal appearance, 4 day fry after hatching with gill raker and body pigment cell mass appearance, 5 day fry after hatching with stomatodeum and gill filament appearance, 6 day fry after hatching with pectoral fin fold, dorsal fin fold and pelvic fin fold appearance, 7 day fry after hatching with nose concave and astral form pigment group appearance, 9 day fry after hatching with swim bladder primordial appearance, 11 day fry after hatching with tail fin appearance with pectoral fin trembled, 13 day fry after hatching with swim bladder one room appearance, semicircular canal formed, 17 day fry after hatching with dorsal fin primordial and pectoral fins formed, 21 day fry after hatching with larger hyomandibular of pelvic fin fold, 28 day fry after hatching with spleen appearance, 33 day fry after hatching with pelvic fin appearance, 34 day fry after hatching with scale appearance, and no difference for the fish 85 day after hatching. Egg diameter of Ptychobarbus dipogon is the largest one among Schizothorax fishes, and its perivitelline space is smaller than four major Chinese carps, which may explain by cold environment at the plateau uplift.