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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 use of sight probably varies with species and water conditions. The shark's field of vision can swap between monocular and stereoscopic at any time. [58] A micro-spectrophotometry study of 17 species of sharks found 10 had only rod photoreceptors and no cone cells in their retinas giving them good night vision while making them colorblind.
Elasmobranch – member of the subclass Elasmobranchii, which includes sharks, rays, and skates. Predator – organism that attacks and feeds on prey (the organism that is attacked). [2] Apex predator – some shark species are apex predators, that is, predators with no predators of their own, residing at the top of their food chain. [3]
The Lamniformes (/ ˈ l æ m n ɪ f ɔːr m iː z /, from Greek lamna "fish of prey") are an order of sharks commonly known as mackerel sharks (which may also refer specifically to the family Lamnidae). It includes some of the most familiar species of sharks, such as the great white [1] as well as less familiar ones, such as the goblin shark ...
The grey reef shark has a typical "reef shark" shape with a broad, round snout and large eyes. This species can be distinguished from similar species by the plain or white-tipped first dorsal fin, the dark tips on the other fins, the broad black rear margin on the tail fin, and the lack of a ridge between the dorsal fins. Most individuals are ...
Scyliorhinidae is a family of sharks, one of a few families whose members share the common name catsharks, belonging to the order Carcharhiniformes, the ground sharks. Although they are generally known as catsharks, some species can also be called dogfish due to previous naming. [ 2 ]
A mysterious shark that may count as the world’s largest predatory fish appears to be in decline off the U.S., prompting a rush to gather as much information as possible about the secretive ...
The bluntnose sixgill is a species of sixgill sharks, of genus Hexanchus, a genus that also consists of two other species: the bigeye sixgill shark (Hexanchus nakamurai) and the Atlantic sixgill shark (Hexanchus vitulus). Through their base pairs of mitochondrial genes COI and ND2, these three species of sixgills widely differ from one another.