Hypuralia

The hypuralia are those with hy. marked bones below the caudal spine

Hypuralia are supporting elements from the tail fin skeleton of the real bony fish (Teleostei). They consist of enlarged hemal arches of the caudal vertebrae and form the base of the caudal fin rays .

source

• Lexicon of Biology. Volume 4, Verlag Herder, Freiburg im Breisgau 1985, ISBN 3-451-19644-1 , p. 326.