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Dorsal fin diagram with landmarks labeled. Fins allow the sharks to be able to guide and lift themselves. Most sharks have eight fins: a pair of pectoral fins, a pair of pelvic fins, two dorsal fins, an anal fin, and a caudal fin. Pectoral fins are stiff, which enables downward movement, lift, and guidance.
The teeth of sharks over 1.4 m (4.6 ft) long are finely serrated. [3] The fins (especially the dorsal, pectoral, and pelvics) of the sicklefin lemon shark are more falcate (sickle-shaped) than those of the otherwise very similar American lemon shark. The first dorsal fin is positioned closer to the pelvic than the pectoral fins.
Dogfish sharks: 3 31 Dogfish sharks have two dorsal fins, each with smooth spines, but no anal fin. Their skin is generally rough to the touch. [18] These sharks are characterized by teeth in upper and lower jaws similar in size; caudal peduncle with lateral keels; upper precaudal pit usually present; and a caudal fin without a
The order Squaliformes is a large, ancient order of sharks. Sharks from this order have two dorsal fins -usually with spines-, no anal fin, and no nictitating membrane on the eyes. Squaliform sharks are extremely variable in size and shape, and can be found in most marine habitats throughout the world.
The sharp fin spines provide a deterrent to being consumed by predators. [2] Bullhead shark egg cases are shaped like an auger, with two spiral flanges. This allows the egg cases to become wedged in the crevices of rocky sea floors, where the eggs are protected from predators; however, some bullhead sharks deposit their eggs on sponges or seaweed.
If you think a normal shark is intimidating enough, try one with two heads. Scientists recently documented a case involving a two-headed embryo among egg-laying sharks and it is believed to be the ...
Mackerel sharks, also called white sharks, are large, fast-swimming sharks, found in oceans worldwide. They include the great white, the mako, porbeagle shark, and salmon shark. Mackerel sharks have pointed snouts, spindle-shaped bodies, and gigantic gill openings. The first dorsal fin is large, high, stiff and angular or somewhat rounded.
Dorsal fin of a shark. ... In these types of fish, the fins are made of two main components. [8] The first component is the dermal fin rays known as lepidotrichia, ...