stegurous

from The Century Dictionary.

• Referring to a type of tail structure, in bony fishes, in which the vertebral column terminates in front of the tail-fin with a vertebra bearing a broad vertical fan-shaped plate which is formed by the fusion of several fin-supports and hemapophyses. This terminal plate generally incloses a short upwardly directed remnant of the notochord or a bony style (urostyle).