Thresher sharks are large sharks found in temperate and tropical oceans around the world. The common name refers to its distinctive, thresher-like tail or caudal fin which can be as long as the body of the shark itself.
Mackerel sharks, also called 'white sharks', are large, fast-swimming sharks, found in oceans worldwide. They include the great white, the mako and the porbeagle shark. Mackerel sharks have pointed snouts, spindle-shaped bodies, and gigantic gill openings. The first dorsal fin is large, high, stiff and angular or somewhat rounded. The second dorsal and anal fins are minute. The caudal peduncle has two or less distinct keels. The teeth are gigantic. The fifth gill opening is in front of the pectoral fin and spiracles are sometimes absent. They are heavily built sharks, sometimes weighing nearly twice as much as sharks of comparable length from other families. Many in the family are among the fastest-swimming fish.
The megamouth shark is an extremely rare species of deepwater shark, and the smallest of the three filter-feeding sharks. Since its discovery in 1976, only a few megamouth sharks have been seen, with 55 specimens known to have been caught or sighted as of 2012, including three recordings on film. Like the basking shark and whale shark, it swims with its enormous mouth wide open, filtering water for plankton and jellyfish. It is distinctive for its large head with rubbery lips. It is so unlike any other type of shark, it is classified in its own family, though it may belong in the family Cetorhinidae of which the basking shark is currently the sole member.
Goblin sharks have a distinctive long, trowel-shaped, beak-like snout, much longer than those of other sharks. The snout contains sensory organs to detect the electrical signals given off by the shark's prey. They also possess long, protrusible jaws. When the jaws are retracted, the shark resembles a grey nurse shark with an unusually long nose. Goblin sharks include one living genus and three extinct genera. There is only known living species, Mitsukurina owstoni.
Sand sharks are so-called because they inhabit sandy shorelines, and are often seen trolling the ocean floor in the surf zone. They are found in warm or temperate waters throughout the world's oceans, except the eastern Pacific. Sand sharks have a large second dorsal fin. They grow up to 10 feet in adult length. The body tends to be brown in color with dark markings in the upper half. These markings disappear as they mature. Their needle-like teeth are highly adapted for impaling fish, their main prey. Their teeth are long, narrow, and very sharp with smooth edges, with one and on occasion two smaller cusplets on either side.
Only one species is in the crocodile shark family. It is a specialized inhabitant of the mesopelagic zone, found worldwide in tropical waters from the surface to a depth of 590 m (1,940 ft). It performs a diel vertical migration, staying below 200 m (660 ft) during the day and ascending into shallower water at night to feed. Typically measuring only 1 m (3.3 ft) in length, the crocodile shark is the smallest living mackerel shark. It can be distinguished by its elongated, cigar-shaped body, extremely large eyes, and relatively small fins. Substantial numbers are caught as bycatch, leading it to be assessed as Near Threatened by the IUCN.
Extinct. The Otodontidae lived from the Paleocene to the Pliocene, and reached huge sizes. There is a disputed possibility that the Carcharocles sharks derived from Otodus, which would mean that Cretolamna would belong in this group. There is also a disputed possibility that megalodon belongs to the group.