|Postembryonic development of the cephalic skeleton in Dicentrarchus labrax (Pisces, Perciformes, Serranidae)|
Gluckmann, I.; Huriaux, F.; Focant, B.; Vandewalle, P. (1999). Postembryonic development of the cephalic skeleton in Dicentrarchus labrax (Pisces, Perciformes, Serranidae). Bull. Mar. Sci. 65(1): 11-36
In: Bulletin of Marine Science. University of Miami Press: Coral Gables. ISSN 0007-4977, more
|Authors|| || Top |
- Gluckmann, I.
- Huriaux, F.
- Focant, B.
- Vandewalle, P., more
At hatching, Dicentrarchus labrax larvae are 3.0 mm long and devoid of any cephalic skeleton. At 3.6 mm, the Meckelian cartilage appears, after which the whole skeleton develops so slowly and gradually that clear-cut stages are impossible to define. Some cephalic elements, however, develop faster than others. Skeletal development is subject to constraints imposed by vital functions such as aquatic respiration and feeding. As the yolk sac shrinks, the branchial parts develop. By the time the vitellus is completely exhausted, the mandible, pharyngeal jaws, hyoid bar, and parts of the suspensorium and operculum are present. Though still incomplete, these structures are probably sufficient to allow ingestion of exogenous food. Further development should enable the larvaes to perform suction feeding, as is typical of perciforms. Before the shift to exogenous feeding, the cartilaginous floor of the skull remains open, but the opening is then closed by the parasphenoid and basioccipital, so the brain is completely isolated from the buccal cavity. The cranial vault and ethmoid region develop later: these structures are probably less essential to fry survival than the earlier and more rapidly developing structures.