Osteological development of the vertebral column and of the caudal complexin Dentex dentex

Osteological development of the vertebral column and caudal complex in comm on dentex was described under extensive larval rearing conditions. Generall y, the cartilaginous bones developed prior to the membranous bents. The dev elopment of the axial skeleton began with the formation of the hypural 1, t he neural arches 2 and 3, as well as the haemal arches 1-8 at 4.8, 4.9 and 5.0 mm total length (L-T, measured in vivo), respectively. By 7.5 mm L-T, a ll the cartilaginous elements were formed, except for the ventral ribs, whi ch formed between the range of 84-180 mm L-T. The caudal lepidotrichia were the first membranous bones to appear (5.3 mm L-T) and attain their full me ristic count (7.4 mm L-T), followed by the vertebral centra, which formed b etween 6.6 and 9.7 mm L-T. By 25.0 mm L-T, all the elements were fully ossi fied except for the ventral ribs. The developmental direction and order of all the elements were studied with respect to their formation and ossificat ion. The results were discussed in the contexts of ichthyoplankton, ecology and aquaculture. Compared with other Sparidae species, common dentex follo wed a pattern of relatively rapid rate of osteological development. (C) 199 9 The Fisheries Society of the British Isles.