绿鳍马面鲀外部形态特征与染色体核型分析

Morphological structure and karyotype of Thamnaconus septentrionalis

该研究以黄海水域捕捞的131尾绿鳍马面鲀(Thamnaconus septentrionalis)为样本,在活鲜状态下,观察其外部形态特征并绘图;统计各鳍条数量,对可量比性状进行回归分析;采用热滴片法,制备染色体标本。结果发现:1)鱼体头部和背部在活体状态下呈深青灰色,腹部呈浅青绿色,趋于白色。死亡后,体色加深,转为墨绿色,鳍条保持蓝绿色为其外部形态的明显特征。2)体长为体高的1.5~3.3倍;体长为头长的3.1~4.9倍;头长为吻长的1.1~1.6倍。3)全长(Tl)/体长(Sl)相关性显著(R^2=0.96),雌雄无显著差异;尾柄长/尾柄高、体长/尾柄长、头长/眼径、头长/眼间距相关性不显著,雌雄差异大。4)鳍式为背鳍Ⅱ,36~39;臀鳍34~37;胸鳍14~15;尾鳍1+10+1;腹鳍退化为一个腹鳍棘。5)鳞片绒状鳞,由基板和骨质凸起组成;具有体侧线和框下线。6)绿鳍马面鲀二倍体染色体数目为2n=40,染色体核型为2n=40t,臂数NF=40,均为端着丝粒染色体,且无异型染色体。

We observed and drawn the external morphology of 131 Thamnaconus septentrionalis collected from the Yellow Sea,and counted the number of dorsal fin rays,caudal fin rays,anal fin rays as well as pectoral fin rays,so as to conduct a regrassion analysis of their morphological features.Besides,the chromosome specimens were made by hot titration method,and the karyotype was analyzed.The results are:1)when alive,the head and back of T.septentrionalis’body were in pewter and the abdomen was in whitish turquoise;after death,the color turned dark green.The fins’remaining turquoise was an obvious feature of its external morphology.2)The body length was 1.5-3.3 times and 3.1-4.9 times as long as the body height and the head length;the head length was1.1-1.6 times as long as the proboscis length.3)The variation of total length/standard length was minimum with the smallest difference between female and male and had the best correlation coefficient(R^2=0.96).The values of caudal length/caudal depth,standard length/caudal length,head length/eye diameter and head length/eye interal had the lowest correlation coefficient,and the difference between female and male was obvious.4)The fin type was:dorsal fin II,36-39;anal fin 34-37;tail fin 14-15,caudal fin 1+10+1,and the pelvic fin degenerated into pelvic fin spines.5)The body was covered with a variety of fleece scales consisting of a base plate and a bony bulge,and the lateral lines were composed of trunk line and infraorbital line.6)T.septentrionalis had 20 pairs of chromosomes(2n=40)and the karyotype formula was 2n=40t.All of them were telomeres without heteromorphic sex chromosomes.