heterocercal

1.abbreviate heterocercal Tail in which the vertebral axis is prominently flexed upward, only partly invading upper lobe of caudal fin, fin fairly symmetrical externally.

普通歪型尾鳍尾部的脊椎轴明显地弯曲向上,只有部伸入尾鳍上叶，鳍的外部大致对称。