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Dorsal fin of a shark. A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom.Many species of animals possessing dorsal fins are not particularly closely related to each other, though through convergent evolution they have independently evolved external superficial fish-like body plans adapted to their marine environments ...
The first dorsal fin is large, high, stiff and angular or somewhat rounded. The second dorsal and anal fins are minute. The caudal peduncle has a few or less distinct keels. The teeth are gigantic. The fifth gill opening is in front of the pectoral fin and spiracles are sometimes absent.
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 sandbar shark (Carcharhinus plumbeus), also known as the brown shark or thickskin shark, is a species of requiem shark, and part of the family Carcharhinidae, native to the Atlantic Ocean and the Indo-Pacific. It is distinguishable by its very high first dorsal fin and interdorsal ridge. [2]
Ground sharks, like this blacknose shark, have a nictitating membrane which can be drawn over the eye to protect it. Carcharhiniformes / k ɑːr k ə ˈ r aɪ n ɪ f ɔːr m iː z /, the Requiem sharks, are the largest order of sharks, with over 270 species. They include a number of common types, such as catsharks, swellsharks, and requiem sharks.
An identifying character of this species is its tall first dorsal fin, which has a slightly rounded tip and originates over the rear tips of the pectoral fins. The Galapagos shark is an active predator often encountered in large groups.
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.
Rough sharks are characterised by two large dorsal fins, each with a sharp spine, and with the first fin placed far forward above the head. Their bodies are compressed, giving them a triangular cross-section. Their skins are even rougher and more prickly than the dogfishes (below). Rough sharks are small to medium in size, ranging from 49 to ...