heterocercal fin

English Thesaurus

1. a tail fin with unequal lobes in which the vertebral column turns upward into the larger lobe as in sharks (noun.animal)

hypernym	:	caudal fin, tail fin,
definition	:	the tail of fishes and some other aquatic vertebrates (noun.animal)

antonym	:	homocercal fin,
definition	:	symmetrical tail fin extending beyond the end of the vertebral column as in most bony fishes (noun.animal)

antonym	:	homocercal fin,
definition	:	symmetrical tail fin extending beyond the end of the vertebral column as in most bony fishes (noun.animal)