Development of the vertebral column and caudal complex in a flyingfish, Parexocoetus mento mento (Teleostei: Exocoetidae)

The developmental pattern of the vertebral column and caudal complex in juvenile (16.9 mm SL) to adult (112.2 mm SL) Parexocoetus mento mento is described. Juvenile external caudal morphology was similar to the adult condition, although juveniles exhibited various internal ontogenetic changes. Osteological development was almost completed at 60-69 mm SL. Complete ossification of the vertebral column and caudal complex appeared to be the optimal condition giving strength for flight. Loss of perforations in the centra, neural and haemal arches may be consistent with the rigid and straightened body position during rake-off. Some ontogenetic changes in the caudal complex were related to functional aspects. Ankylosis of the NPU2 spur to the uroneural notch, fusion of hypurals 3+4 and 5 and the elongated hypural 1+2 (lower hypural) were linked to the acquisition of stability and strength in the caudal complex.