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Sharks generally reach sexual maturity only after many years and produce few offspring in comparison to other fish species. [ 9 ] Conservationists estimate that up to 100 million sharks are killed by commercial and recreational fishing every year.
There are more than 500 species of sharks split across thirteen orders, including several orders of sharks that have gone extinct: [26] [27] ... Many sharks ...
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 556 described and 23 undescribed species in eight orders. The families and genera within the orders are listed in ...
Sharks could be facing extinction over the next couple of decades. Human interference is largely to blame for the species interference. Overfishing of sharks has increased as the global demand has ...
Extinct: Hexanchidae: Cow sharks: 3 extant 5 extinct 5 extant 31 extinct Cow sharks are considered the most primitive of all the sharks, because their skeletons ...
In this model, the great white shark is more closely related to the extinct broad-toothed mako (Cosmopolitodus hastalis) than to megalodon, as evidenced by more similar dentition in those two sharks; megalodon teeth have much finer serrations than great white shark teeth.
The frilled shark eats a diet of cephalopods, Nudibranchs, smaller sharks, and bony fish; [2] 60 percent of the diet is composed of squid varieties, such as the Chiroteuthis, the Histioteuthis, and the Onychoteuthis, the Sthenoteuthis and the Todarodes; [17] and other sharks, as indicated by the stomach contents of a 1.6 m (5.2 ft)–long ...
Helicoprion is a genus of extinct shark-like [1] eugeneodont fish. Almost all fossil specimens are of spirally arranged clusters of the individuals' teeth, called "tooth whorls", which in life were embedded in the lower jaw. As with most extinct cartilaginous fish, the skeleton is mostly unknown.