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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 members of the order Hexanchiformes have only a single
The first dorsal fin is positioned closer to the pelvic than the pectoral fins. The second dorsal fin, nearly equal to the first in size, is located over or slightly forward of the anal fin. No ridge is seen between the dorsal fins. The pectoral fins are long and broad, originating below the space between the third and fourth gill slits.
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 second dorsal fin is relatively large with a short rear margin, and is placed opposite the anal fin. There is no ridge between the dorsal fins. This shark is a pale grayish-brown above and white below, with an obvious white band on the sides extending forward from above the anal fin. All the fins have black tips highlighted by lighter ...
The fin spines of reef-dwelling horn sharks are shorter than those living in algal habitats, as their spines become worn down on rocks from the sharks' movements. [3] The first dorsal fin originates over the bases of the large pectoral fins, while the second dorsal fin originates slightly anterior to the free rear tips of the pelvic fins.
On the single body, there were four anticipated dorsal fins, two anterior, right and left and two posterior, right and left." Experts say animals with such a condition have a difficult time ...
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.
According to biologists, the dorsal fin’s size in such shallow water should reveal part of the shark’s back or a second dorsal fin — neither of which are visible.