珠江卷口鱼形态特征与染色体组型

Morphological character and karyotype of Ptychidio jordani Myers in Pearl River

对珠江卷口鱼形态特征和染色体组型进行了初步研究。在珠江干流西江的肇庆、郁南、桂平以及其上游柳江的柳州采集野生卷口鱼450余尾,全长165～236 mm,体重167.84～586.25 g。随机选取试验鱼进行观察、解剖、测量和拍照。发现卷口鱼具有形态多样性。在体型上,一种体高较高,为高背型,主要来自桂平极其下游;另一种为平背型,主要来自柳州及上游。在体色上,腹部颜色变异较大。腹部颜色有乳白色、黄色和棕黑色三种。无雌雄异型现象。卷口鱼口下位,内卷;咽齿较发达,鳞中等大,侧线鳞式37～46,5～8/5～6-A。胃不发达,肠长为体长的1.36～1.51倍。肋骨14,脊椎骨38-40。以肾脏为材料,用空气干燥法制备染色体标本,卷口鱼的染色体数目为2n=50,核型公式为12 m+16 sm+18 st+4 t,NF=78。

Ratmouth barbel （Ptychio jordani Myers） is a member of the family Cyprinidae and is mainly distribute in Pearl River of southern China, especially in Xijiang River - the branch of Pearl River. It has high values for food and for aquaculture in China. In this paper, the morphology and karyotype of ratmouth barbel collected from Pearl River were studied and analyzed. More than 450 individuals with length from 165mm to 236 mm and weight from 167.8 g to 586.3 g were collected from Pearl River in Zhaoqian, Yunan, Guiping and Liuzhou. Two kinds of shape of ratmouth barbel were found. One has a high back mainly from Guiping and lower reaches of Pearl River and another has a flat back from Liuzhou and upper reaches of Pearl River. There are three different colors, milk-white and yellow and brown, at abdomen of ratmouth barbel. No sexual differences in morphology were found. The mouth of ratmouth barbel is on the base of head and rolls inside. The pharynx teeth are powerful and scale is middling size. The scale formula on lateral line is 37 -46,5 -8/5 -6-A. Stomach is thin and the length of intestines is 1.36 -1.51 times ofbody length. There are 14 pairs of ribs and 38 -40 vertebras. The number of diploid chromosome is 2n =50 and the karyotype formula is 12 m ＋16 sm ＋18 st ＋4 t, NF =78.