Lamniformes

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Lamniformes
Temporal range: Early Cretaceous–Recent[1]
Great white shark, Carcharodon carcharias
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Selachimorpha
Order: Lamniformes
L. S. Berg, 1958
Families

See Text

The Lamniformes or mackerel sharks (which may also refer specifically to the family Lamnidae) are an order of sharks. It includes some of the most familiar species of sharks, such as the great white shark, as well as more unusual representatives, such as the goblin shark and the megamouth shark.

Members of the order are distinguished by possessing two dorsal fins, an anal fin, five gill slits, eyes without nictitating membranes, and a mouth extending behind the eyes.

Species[edit]

The Lamniformes include seven families, with a total of 17 living species:

Family Image Common name Genera Species Description
Alopiidae Threshershark.jpg Thresher sharks 1 4[2] 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.
Cetorhinidae Cetorhinus maximus by greg skomal.JPG Basking sharks 1 1 The basking shark is the second-largest living fish, after the whale shark, and the second of three plankton-eating sharks, the other two being the whale shark and megamouth shark. It is a cosmopolitan migratory species, found in all the world's temperate oceans. It is generally a harmless filter feeder with a greatly enlarged mouth, which cruises leisurely over huge distances covering three miles every hour. During each of those hours, it strains about 1.5 million litres of water through more than 5,000 gill rakers for plankton.[3] Basking sharks have long been important to commercial fishing, as a source of food, shark fin, animal feed, and shark liver oil. Overexploitation has reduced its populations to the point where some have disappeared and others need protection.
Lamnidae White shark.jpg Mackerel sharks 3 5 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.
Megachasmidae Megamouth shark Megachasma pelagios.jpg Megamouth shark 1 1 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.
Mitsukurinidae Goblin Shark.gif Goblin sharks 1 1 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.[4] They also possess long, protrusible jaws.[5] 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.[6] There is only known living species, Mitsukurina owstoni.
Odontaspididae Grey Nurse Shark at Fish Rock Cave, NSW.jpg Sand sharks 2 4 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.[1] Sand sharks have a large second dorsal fin. They grow up to 10 feet in adult length.[1] 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.[7]
Pseudocarchariidae Pseudocarcharias kamoharai.jpg Crocodile sharks 1 1 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.
†Cretoxyrhinidae Cretoxyrhina mantelli 21DB.jpg †Cretoxyrhinidae 7 Extinct. The Cretoxyrhinidae include Cretoxyrhina (pictured), a genus from the Cretaceous, and Palaeocarcharodon, a possible ancestor of the great white shark and megalodon, possibly the largest shark to have lived.[8]
†Otodontidae VMNH megalodon.jpg †Otodontidae 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.[9]

Sustainable consumption[edit]

In 2010, Greenpeace International added the shortfin mako shark (Isurus oxyrinchus) to its seafood red list. [10]

References[edit]

  1. ^ a b c Froese, Rainer, and Daniel Pauly, eds. (2009). "Lamniformes" in FishBase. January 2009 version.
  2. ^ Froese, Rainer, and Daniel Pauly, eds. (2013). "Alopiidae" in FishBase. October 2013 version.
  3. ^ Basking shark BBC Nature, 13 March 2013. Retrieved 28 March 2013.
  4. ^ Stevens, J. & Last, P.R. (1998). Paxton, J.R. & Eschmeyer, W.N., ed. Encyclopedia of Fishes. San Diego: Academic Press. p. 63. ISBN 0-12-547665-5. 
  5. ^ Froese, Rainer and Pauly, Daniel, eds. (2005). "Mitsukurina owstoni" in FishBase. 10 2005 version.
  6. ^ Mikko's Phylogeny Archive
  7. ^ Bigelow, Henry B.; Schroeder, William C. (1953). Fishes of the Gulf of Maine. United States Government Printing Office. Retrieved 30 October 2011. 
  8. ^ Mikko's Phylogeny Archive
  9. ^ Joseph S. Nelson (2006). "Order Lamniformes". Fishes of the World (4th ed.). John Wiley and Sons. pp. 57–60. ISBN 978-0-471-25031-9. 
  10. ^ Greenpeace International Seafood Red list

Further reading[edit]

External links[edit]