胭脂鱼仔幼鱼的咽齿发育及其系统学意义

DEVELOPMENT OF THE LARVAL AND JUVENILE PHARYNGEAL DENTITION IN Myxocyprinus asiaticus AND ITS SYSTEMATIC SIGNIFICANCE

本文报道了胭脂鱼咽齿个体发育的研究结果。与鲤科鱼类咽齿的个体发育相比较,两者的早期发生相同,而以后随个体的生长发育,出现了不同的发育模式。在胭脂鱼咽齿发育过程中,常见有4列不同发育期的齿列井存的特殊形式。依据观察所见的性状分析,亚口鱼科比鲤科具有更多的祖征,表明其在系统发育上处于较原始的位置。

Most species of the family Catostomidae are distributed in North America and so far only one species Myxocyprinus asiaticus has been reported in China. There is a necessity of studying the development of pharyngeal dentition of larval and juvenile in M. asiaticus as a research of the special subject.At the earliest stage of pharyngeal dentition in larval, catostomids and cyprinids are similar both in their external features and arrangments. Thereafter, they develop into two different ontogenetic types.In catostomids, it is more special that four rows of teeth coexist simultaneously, but among them only one row of functional teeth in the process of development is ankylosed at the pharyngeal bone. Mary plesiomorphies it has, such as the shape of whole pharyngeal teeth is similar to the ceratobranchials of the four front gill arches and the ankylosed teeth preserve the original form of gill rakers etc. It is concluded, that the catostomids is more primitive in phylogeny of suborder Cyprinoidei.