矛尾虾虎鱼仔稚鱼脊柱及附肢骨骼系统的发育观察

采用软骨-硬骨双染色技术,研究矛尾虾虎鱼(Chaeturichthys stigmatias)仔稚鱼(体长范围为4.7~45.1 mm)脊柱及附肢骨骼系统的形态发育特征。结果显示:4.7 mm个体脊索为无分节的长圆柱形;5.3 mm个体随着髓弓、脉弓和尾下骨的出现,脊柱开始发育;7.1 mm个体髓弓与脉弓延伸形成髓棘与脉棘,脊柱出现分节的硬骨环,并从前往后硬骨化;22.9 mm个体脊柱形成40~43枚椎骨(躯椎15枚,尾椎25~28枚)。矛尾虾虎鱼附肢骨骼系统的发育顺序依次为胸鳍、尾鳍、第二背鳍与臀鳍、第一背鳍与腹鳍。4.8 mm个体可见软骨质的胸鳍支鳍骨和乌喙骨-肩胛软骨,以及部分骨化的匙骨;16.8 mm个体肩带开始骨化。腹鳍支鳍骨最早在8.9 mm个体出现,在17.0 mm个体开始骨化。6.6 mm个体脊索上方中部与肛门后端分别出现13和11枚软骨质的支鳍骨;第二背鳍先于第一背鳍出现,背鳍支鳍骨与臀鳍支鳍骨分别在13.0 mm和12.1 mm个体中开始由前向后骨化,第二背鳍与臀鳍第1枚鳍条分别在22.7 mm和20.6 mm个体中锐化成背棘与臀棘。5.8 mm个体最早出现2枚尾下骨,随着脊索末端向上弯曲,10.9 mm个体尾鳍基本成型,共有2枚尾上骨、1枚尾杆骨、1枚尾椎髓体、1枚侧尾下骨和3枚尾下骨,且第2枚与第3枚尾下骨已愈合完全,24.3 mm个体尾鳍骨化基本完成。矛尾虾虎鱼仔稚鱼骨骼发育研究结果对其分类鉴定和早期发育功能趋向有重要作用。

Development of the vertebral column and appendicular skeleton in larvae and juveniles of Chaeturichthys stigmatias

In this study, the development of vertebral column and appendicular skeleton of the larvae and juveniles of Chaeturichthys stigmatias were described. A series of wild specimens of 4.7~45.1 mm in body length were cleared and stained for both cartilage and bone. The observation showed that the notochord was not segmented, which seemed a cone in specimen 4.7 mm NL. With the appearance of neural arches, haemal arches and hypurals in specimen 5.3 mm NL, the vertebral column started to develop. The neural and haemal arches in specimen 7.1 mm NL extended to neural and haemal spines, respectively. Segmental bone rings formed in specimen 7.1 mm NL. The ossification of vertebral column from anterior to posterior, and completely ossified in specimen 22.9 mm SL. The trunk and caudal vertebra were formed 15 and 25~28 cervical vertebra segments, respectively. The appendicular skeleton developed in the following sequences: pectoral fins, caudal fins, second dorsal fins and anal fins, first dorsal fins and pelvic fins. Cartilage of pterygiophore of pectoral fins, coracoid-scapula cartilage, and partially ossified cleithrum were observed in specimen 4.8 mm NL. The pectoral girdle was ossified in specimen 16.8 mm SL. The pelvic fins began to formed in specimen 8.9 mm SL, and ossifying occurred in specimen 17.0 mm SL. The development of dorsal fins and anal fins began with the appearance of 13 and 11 hyaloidin pterygiophores in specimen 6.6 mm NL. The second dorsal fin was formed earlier than the first dorsal fin. The dorsal fins and anal fins began to ossify from anterior to posterior in specimen 13.0 mm SL and specimen 12.1 mm SL, respectively. The first fin rays of second dorsal fins and anal fins were transformed dorsal spine and anal spine in specimen 22.7 mm SL and specimen 20.6 mm SL. The development of the caudal fin began with the appearance of the hypurals in specimen 5.8 mm NL. The caudal fin was basically formed, with two pieces of epural, one piece of urostyle, one piece of uroneural, one piece of parhypural and three pieces of hypurals, and the second and third hypurals were combined together in specimen 10.9 mm SL. The caudal fin was ossified in specimen 24.3 mm SL. The study on the early development of the vertebral column and the appendicular skeleton in C. stigmatias is important for classification and functional adaptation during early development environment.