Search results
Results from the WOW.Com Content Network
The tail of a shark consists of the caudal peduncle and the caudal fin, which provide the main source of thrust for the shark. Most sharks have heterocercal caudal fins, meaning that the backbone extends into the (usually longer) upper lobe. The shape of the caudal fin reflects the shark's lifestyle, and can be broadly divided into five categories:
Sharks possess a heterocercal caudal fin in which the dorsal portion is usually noticeably larger than the ventral portion. This is because the shark's vertebral column extends into that dorsal portion, providing a greater surface area for muscle attachment.
It has three dorsal and two anal fins. Types of caudal fin: heterocercal (A), protocercal (B), homocercal (C), and diphycercal (D) Sharks possess a heterocercal caudal fin. The dorsal portion is usually larger than the ventral portion. The high performance [definition needed] bigeye tuna is equipped with a homocercal caudal fin, finlets and keels.
Sharks possess a heterocercal caudal fin in which the dorsal portion is usually noticeably larger than the ventral portion. This is because the shark's vertebral column extends into that dorsal portion, providing a greater surface area for muscle attachment.
Named for their exceptionally long, thresher-like heterocercal tail or caudal fins (which can be as long as the total body length), thresher sharks are active predators; the tail is used as a weapon to stun prey. [12] [13] The thresher shark has a short head and a cone-shaped nose.
This species is a ground shark and has a heterocercal caudal fin bearing an elongate upper lobe, triangular and broad dorsal fins, broad pectoral fins, an inferior mouth, and large eyes, and displays a reddish or bronze coloration from above and a silverish coloration on the underside. [7]
It has been referred to as a freshwater shark because of its heterocercal tail or caudal fin resembling that of sharks, though it is not closely related. [7] The American paddlefish is a highly derived fish because it has evolved specialised adaptations such as filter feeding.
The caudal fin is elongated with a long upper lobe (i.e. strongly heterocercal). They have two large, broad-based grey dorsal fins set back beyond the pectoral fins. [2] The sand tiger shark has a grey-brown back and pale underside. Adults tend to have reddish-brown spots scattered, mostly on the hind part of the body. [6]