caudal principal ray set
Anatomical cluster including all segmented-and-branched rays plus one unbranched but segmented ray located at the leading margin in each lobe of the caudal fin (Hubbs and Lagler, 1947) and that associates with endoskeletal elements such as hypurals and hemal spines of preural centra 1 and 2 (Arratia, 2008). Caudal principal rays are counted from the dorsalmost one ventrally. Caudal principal rays are unpaired median bones.