OBO_REL:part_of (UNDECLARED) epural epiural apophysis A free, modified neural spine of a preural or a ural vertebra that is placed between the last developed neural spine of a preural centrum and the dorsal axis (= anterior margin of first uroneural) of the caudal skeleton . An epural commonly supports one or more dorsal procurrent rays. An epural is an unpaired median perichondrally ossified bone. TAO:0000660 The origin of the epurals is unclear, three hypotheses have been proposed: 1) The epurals are modified radials or dorsal radials; 2) the epurals are detached neural spines and may support fin rays; and 3) the epurals are a serial homologue of the supraneuralia. At least in teleosts the epural is a detached neural spine. For details see Schultze and Arratia (1989) and Arratia and Schultze (1992). epiural epurals teleost_anatomy éphural (French) épural (French) neural spine caudal fin skeleton