OBO_REL:part_of (UNDECLARED) caudal vertebra preural vertebra Caudal vertebra that is one of the last caudal vertebrae anterior to the ural vertebrae that with its neural and haemal spines supports the procurrent caudal fin rays or lepidotrichia. The numbering of preural vertebrae is from caudal to rostral direction. TAO:0000734 The term preural vertebra was created by Nybelin (1963) for those vertebrae supporting caudal procurrent rays. For additional information see Arratia and Schultze (1992). Their neural and hemal arches may or may not be fused to their corresponding autocentrum. Fusion or separation of certain neural and/or haemal arches of preural centra is characteristic or certain teleosts subgroup. The boundary between preural and ural region is determined by the bifurcation of the four or five blood vessels running inside the hemal arches of the preural vertebrae (primary caudal artery, two secondary arterial trunks, primary caudal vein, and secondary subvertebral vein) (for details see Schultze & Arratia, 1989). The bifurcation of the caudal artery and vein was proposed as a landmark to homologize preural centrum 1 throughout actinopterygians (Nybelin, 1963). caudal fin vertebra specialized centra/vertebrae teleost_anatomy caudal fin skeleton