part of part of caudal principal ray caudal principal lepidotrichium caudal fin principal ray This class was sourced from an external ontology (teleost_anatomy). Its definitions, naming conventions and relationships may need to be checked for compatibility with uberon Caudal fin lepidotrichium that is adjacent to a branched ray. Caudal principal rays may be segmented but unbranched and the main element forming the dorsal or ventral leading margin of the caudal fin or a ray that may be only segmented-and-branched and forms part of the middle-posterior region of the fin. A caudal principal ray is an unpaired median bone. UBERON:2001585 ZFA:0001585 Counts of caudal principal rays are taken as the number of branched rays plus two adjacent unbranched rays and counts are typically reported as, for example: 1,8,7,1 (1 unbranched and 8 branched upper rays, 7 branched and 1 unbranched lower rays). A caudal principal caudal ray may be associated with one or more hypurals or with hemal spines of preural centra 1 and 2 (Schultze and Arratia, 1989; Arratia, 2008). In basal teleosts the number of caudal principal rays is about 20. A decreasing of the number of the branched-and segmented rays is observed in more advanced teleosts (see Schultze and Arratia, 1989; Arratia, 1991, 2008). caudal principal ray set caudal fin lepidotrichium