ABSTRACT
The sophisticated improvements, during the five to six last decades to manage the mineralized tissues in association with the recent great development of 3D computering had allowed important progress of the knowledge of osteichthyan mineralized skeleton. The present chapter deals with fish skeletal tissues that regroup bones, cartilages, teeth, and some specialized unmineralized conjunctive tissues like the basal plate in the scales of numerous teleosteans. We describe two types of bony tissues : “cellular bone” with embedded cells (the osteocytes) and “acellular bone” that is completely devoid of enclosed cells. These well alive bony tissues that show a more or less developed remodelling assume various physiological functions, notably exchanges between bone and the internal environment of fishes, thus participating in various homeostasic activities under hormonal control. Moreover, skeleton grows leading to changes of bone morphology (the skeletal growth marks) and proportion (modelling of bone) without loss of any action of mechanical functions. Concerning teeth, we point to recent descriptive novelties in several predatory fishes: the plates of the dentine wall in the pulp cavity that is named “simplexodont” plicidentine. These various comparative histological data provide the basis of a general discussion of the evolutionary trends of bony tissues and their derivatives in Osteichthyes.
