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Guitarfish have a body form intermediate between those of sharks and rays. The tail has a typical shark-like form, but in many species, the head has a triangular, or guitar-like shape, rather than the disc-shape formed by fusion with the pectoral fins found in other rays.
The thresher sharks have an extreme example of this tail in which the upper lobe has evolved into a weapon for stunning prey. Bottom-dwelling sharks such as catsharks and carpet sharks have tails with long upper lobes and virtually no lower lobe. The upper lobe is held at a very low angle, which sacrifices speed for maneuverability.
The pectoral fins have fused to the branchial region of the head, the body begins to gain pigment, and the eyes have developed. When stage four is reached, the embryos still have an external yolk sac, but entirely resemble adults. The dorsal surface is brown and spots on the snout have developed. Claspers in males at this stage also become visible.
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Rhina ancylostoma, also known as the bowmouth guitarfish, shark ray or mud skate, is a species of ray and a member of the family Rhinidae.Its evolutionary affinities are not fully resolved, though it may be related to true guitarfishes and skates.
Generally, only young sharks are encountered in shallow water, as the adults prefer depths greater than 9 m (30 ft) and is most common at 18–64 m (59–210 ft). [ 1 ] [ 7 ] Blacknose sharks in the South Atlantic Bight (off the Atlantic coast of the southern United States) migrate northward in the summer and southward (or possibly offshore) in ...
With his hand close to razor sharp teeth, shark expert Neil Harvey attempts tonic immobility in a large reef shark. Tonic can be induced by turning a shark upside down, but that's not the only way.
"We have to think about it in terms of the food web that's out in the ocean: Ultimately, at the very top of that cycle of life are the sharks and if we removed the sharks, smaller fish species ...