Sequence of caudal fin development starting from hatching until the larval period in Notopterus notopterus. (a) shortly after hatching, day 7; (b) hemal spines and hypural plates (hh) emerged; note the slight regression of fin fold, day 10; (c) fin fold dorsally relatively lower, but intact, caudally completely replaced by 10 caudal fin rays, pterygiolarval phase, stage 30, day 20; (d) well-developed caudal fin in an early juvenile stage 33 in perfect continuity with the anal fin, day 36;Cfm – caudal fin mesenchyme; ff- fin folds; cfr – caudal fin rays; cf – caudal fin; af – anal fin. Arrows indicate the approximate border between caudal and anal fin. Scale bar = 2 mm.