lower hypural set
Anatomical cluster including hypurals 1 and 2 that supports part of the ventral principal caudal lepidotrichia or rays and that separates from the dorsal hypural set through the hypural diastema. The lower hypural set articulates or fuses to ural centra 1 and 2 (polyural terminology) or ural centrum 1 (diural terminology) depending on the teleost subgroup. The lower hypural set is composed of unpaired median bones.