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Dorsal fin diagram with landmarks labeled. Fins allow the sharks to be able to guide and lift themselves. Most sharks have eight fins: a pair of pectoral fins, a pair of pelvic fins, two dorsal fins, an anal fin, and a caudal fin. Pectoral fins are stiff, which enables downward movement, lift, and guidance.
Squalicorax, commonly known as the crow shark, is a genus of extinct lamniform shark known to have lived during the Cretaceous period. The genus had a global distribution in the Late Cretaceous epoch. Multiple species within this genus are considered to be wastebasket taxon due to morphological similarities in the teeth.
Any fossils, including fossil shark teeth, are preserved in sedimentary rocks after falling from their mouth. [13] The sediment that the teeth were found in is used to help determine the age of the shark tooth due to the fossilization process. [15] Shark teeth are most commonly found between the Upper Cretaceous and Tertiary periods. [16]
The kitefin shark, the largest luminous vertebrate on record, [3] has a slender body with a very short, blunt snout, large eyes, and thick lips. Its teeth are highly differentiated between the upper and lower jaws, with the upper teeth small and narrow and the lower teeth large, triangular, and serrated.
Simplified diagram of shark net. Drum lines; Shark net – submerged net placed around beaches to reduce shark attacks on swimmers; Shark proof cage – cage from which a SCUBA diver can examine sharks more safely; Shark repellent – method of driving sharks from an area, object, person, or animal
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.
Researchers found fossilized teeth belonging to “the immediate ancestor of the giant megalodon shark,” Moore said. “This shark evolved into the megalodon, which was the largest of all sharks ...
Heterodontiformes is an order of sharks in the superorder Galeomorphii. It includes the bullhead sharks (genus Heterodontus ), and several extinct genera. The earliest known members of the group are from the Early Jurassic ( Toarcian ), around 175 million years ago.