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How does the skeleton of a shark differ from the skeleton of a bony fish?
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chondrichthyan
Southern stingrays (Dasyatis americana or Hypanus americanus) are found in the western Atlantic Ocean.
The primary difference between the skeleton of a shark and that of a bony fish lies in the composition of their internal structures.
- Composition: Sharks, which belong to the class Chondrichthyes, possess a skeleton composed entirely of cartilage. While this cartilage may sometimes be reinforced by calcium deposits, it is never replaced by true bone. In contrast, bony fishes (superclass Osteichthyes) have skeletons that are at least partially composed of true bone.12
- Vertebral Column: Sharks and rays retain a cartilaginous vertebral column. Bony fishes possess spool-shaped vertebrae that have replaced the notochord to a greater extent than in cartilaginous fishes.1
- Skull and Gills: The skull, jaws, and gill arches of bony fishes are fully or partially ossified. Furthermore, bony fishes have evolved a bony covering for the gill chamber known as the operculum, whereas sharks retain individual gill slits.13
These skeletal differences reflect distinct evolutionary paths, with bony fishes developing more rigid, ossified structures compared to the flexible, cartilaginous framework of sharks.14