Key features:
* "Sword" (rostrum): This elongated, flattened beak is not actually a bone, but rather a bony extension of the upper jaw. It is incredibly strong and used for stunning prey and fighting rivals.
* Skull: The skull is also very strong, with thick bones that help protect the brain and support the rostrum.
* Skeleton: Their skeleton is mostly made of cartilage rather than bone, which makes them more flexible and agile. This is unusual for a large fish, and contributes to their streamlined shape.
* Vertebrae: Their vertebral column is flexible, allowing them to make sharp turns and maneuvers.
* Musculature: Their powerful muscles are attached to the bones and cartilage, providing immense power for swimming and hunting.
Adaptions for speed and agility:
* Streamlined body shape: The swordfish's body is torpedo-shaped, which reduces drag and allows for efficient movement through water.
* Large tail: Their powerful tail is used for propulsion and quick bursts of speed.
* Dorsal fin: The single, large dorsal fin provides stability and control while swimming.
Overall, the swordfish's bone structure is a perfect example of form following function. It is designed for speed, agility, and strength, making them highly successful predators.