Osteological development of Dentex dentex (Osteichthyes: Sparidae): dorsal, anal, paired fins and squamation

Abstract

The osteological development of dorsal, anal and paired fins and the squamation in common dentex, Dentexdentex (Linnaeus, 1758), was studied under extensive larval rearing conditions. The ontogeny of the fins was determined in three stages: (1) the yolk-sac and the early larval stage (up to 6.7 mm in vivo total length, TL), in which the majority of the elements of the pectoral fins and the predorsals, dorsal and anal proximal pterygiophores formed; (2) the late larval stage (up to 11.6 mm TL), in which the majority of the pectoral lepidotrichia, the lower extrascapulae, all the elements of the pelvic fins, as well as the lepidotrichia, spines and the distal radials of the rest fins developed; and (3) the metamorphosis stage (up to 24.0 mm TL), when the upper extrascapulae formed and the pectoral lepidotrichia attained their full count. The ontogeny of squamation was carried out during the metamorphosis stage; it started at 13.4 mm TL with laterally symmetric points on the middle of each side of the body, followed by one ventral centre (15.6 mm TL) which was located anterior to the pelvic fins, and two bilateral pairs of centres which appeared on the head (17.8 and 21.2 mm TL). The results are discussed from a functional viewpoint and in comparison with the fin and scale ontogeny of other teleosts.