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"Typical sharks", such as requiem sharks, have tails with the upper lobe longer than the lower. The upper lobe is turned upwards at a moderate angle relative to the body, which balances cruising efficiency with turning ability. The thresher sharks have an extreme example of this tail in which the upper lobe has evolved into a weapon for ...
A distinctive dark blotch at the tip of the snout is most obvious in young sharks. The tips of the second dorsal fin, upper caudal fin lobe, and sometimes the lower caudal fin lobe, are dark. Blacknose sharks are typically 1.3–1.4 m (4.3–4.6 ft) long and 10 kg (22 lb) in weight.
The Borneo shark (Carcharhinus borneensis) is a species of requiem shark, ... The asymmetrical caudal fin has a well-developed lower lobe and a longer, narrow upper ...
The first shark-like chondrichthyans appeared in the oceans 400 million years ago, [1] developing into the crown group of sharks by the Early Jurassic. [2] Listed below are extant species of shark. Sharks are spread across 512 described and 23 undescribed species in eight orders. The families and genera within the orders are listed in ...
The asymmetrical caudal fin has a strong lower lobe and a longer upper lobe with a ventral notch near the tip. [4] [5] The dermal denticles mostly do not overlap; each has three to five horizontal ridges leading to posterior teeth, with the central one the longest. This shark is plain gray to slate above and whitish below, with a faint lighter ...
Furthermore, this shark has prominent black tips on its pectoral fins, second dorsal fin, and caudal fin lower lobe. The Pondicherry shark is critically endangered. It was once found throughout Indo-Pacific coastal waters from the Gulf of Oman to New Guinea, and is known to enter fresh water. Fewer than 20 specimens are available for study, and ...
The velvet belly is a robustly built shark with a moderately long, broad, flattened snout. The mouth has thin, smooth lips. The upper teeth are small, with a narrow central cusp and usually fewer than three pairs of lateral cusplets. The lower teeth are much larger, with a strongly slanted, blade-like cusp at the top and interlocking bases.
The tiger shark must be able to twist and turn in the water easily when hunting to support its varied diet, whereas the porbeagle shark, which hunts schooling fish such as mackerel and herring, has a large lower lobe to help it keep pace with its fast-swimming prey. [38]