日本鬼鲉脊柱和附肢骨骼的早期发育

Early development of the vertebral column and the appendicular skeleton in the Inimicus japonicus

通过软骨-硬骨双染色的方法对日本鬼鲉从初孵仔鱼到35日龄的发育过程中脊柱和附肢骨骼的发育进行系统观察。结果显示,脊柱的发育以10日龄髓弓的出现和11日龄脉弓的发育为起点;其中,椎体、髓棘、脉棘在20日龄形成,至35日龄基本完成骨化并伴随着躯椎的弯曲,并且发育和骨化顺序均为从前向后。附肢骨骼的发育顺序依次为胸鳍、尾鳍、臀鳍、背鳍和腹鳍。胸鳍的发育以3日龄胸鳍的匙骨、支鳍骨原基的出现为起点,11日龄软骨质的胸鳍支鳍骨形成,35日龄胸鳍下端支鳍骨游离。腰带和腹鳍出现较晚,在18日龄开始发育,但发育较快。背鳍和臀鳍出现在20日龄,23日龄时出现完整背鳍和臀鳍形态,并伴随着鳍棘的发生;背鳍从身体中部出现,此后鳍棘由前向后发育,而臀鳍从身体中部向后发育。尾鳍发育以8日龄仔鱼尾下骨的发育为起点,15日龄尾鳍基本成型,尾下骨和尾鳍条分为上下两部分。35日龄尾鳍支鳍骨形成并初步完成骨化。对日本鬼鲉脊柱和附肢骨骼的早期发育研究,为早期发育过程中的功能适应性研究提供依据。

Abstract： Inimicus japonicus is one of the most commercially important marine fishes in China and Japan. The embryonic and morphological development of larvae of this species has been studied, but it is incompletely known about its osteological development. In order to obtain the knowledge of the normal onset of skeletal structures throughout development, the developmental sequences of vertebral column and the appendicular skeleton were examined in laboratory-reared larvae of lnimicus japonicus from hatching through 35 days after hatching（d, a. h）by the the clearing and staining technique of cartilage and bone. According to the observation,the vertebral column started to develop from haemal arches and neural arches at 10 d. a. h and 11 d. a. h respectively. Then, centrum, medullary spines, and pulses spines were formed at 20 d. a. h. and they were completely ossified by 35 d. a. h with trunk vertebrae flexion. The development sequence and ossification of centrum, medulllary spines, and pulses spines both started from anterior to posterior. The appendicular skeleton developed in following sequences：the pectoral fin is the first to develop, followed by caudal fins, anal fins, dorsal fins, and then ventral fins. The pectoral fin started to develop from the cleithrum and the fin plate at 3 d. a. h. Cartilages of pterygiophore of pectoral fin were formed at 11 d. a. h and some fin-supports of pectoral fins separated at 35 d. a. h. Pelvic girdle and ventral fin appeared right at 18 d. a. h, later than pectoral fin, but they are rapidly developmented. Dorsal and anal fin appeared at 20 d. a. h, and dorsal and anal fin-ray complements completed at 23 d. a. h. However,anal fin developed posterior from the middle section. The development of the caudal fin began with the appearance of the hypural at 8 d. a. h,and then caudal fin rays and fin-supports begin to develop. Caudal fin was basically formed at 15 d. a. h with two leaves a fin bone formation,which divided the caudal fin rays into two parts. The caudal fins bone formed and started preliminary ossification at 35 d. a. h. Previously-recognized critical periods for Inimicus japonicas, corresponded to transformation phases from the primitive, basic modes to stable, more functional modes in both swimming functional development and changing in living habits. The study of the development of the vertebral column and the appendicular skeleton of Inimicus japonicas will provide the basis for the functional adaptation during early development.