Lamniformes

A Great White Shark; a prime example of the Lamniformes

The **Lamniformes** (from the Greek word, *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 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. Also, unlike other sharks, they maintain a higher body temperature than the surrounding water.

## Species and Taxonomy

The order Lamniformes includes 21 families with at least 16 species, with a total of seven living families and 17 living species. Species marked with a "†" are classified as extinct.

Order **Lamniformes**

* Family Alopiidae  (thresher sharks)- The thresher sharks are a family of lamniformes that possess tails with elongated upper lobes. The whiplike tail is a feature used in disabling prey.
	+ Genus *Alopias*
		- *Alopias pelagicus*  (pelagic thresher)
		- *Alopias superciliosus* (bigeye thresher)
		- *Alopias vulpinus* (common thresher)
		- *Alopias* sp. (not yet described)
		- *Alopias grandis* †
		- *Alopias palatasi*†

* Family Anacoracidae (crow sharks)- Crow sharks are an extinct family of lamniform sharks that were common during the Mesozoic era. Crow sharks had hooked teeth similar to the extant tiger shark's for sawing through flesh.
	+ Genus †*Squalicorax*
	+ Genus †*Telodontaspis*
	+ Genus †*Myledaphus*

* Family Cetorhinidae (basking sharks)- A family with only one species, this is a filter-feeding shark that feeds on zooplankton, krill and small fish.
	+ Genus *Cetorhinus*
		- *Cetorhinus maximus* (basking shark)

* Family †Eoptolamnidae - An extinct family of sharks, it has only one genus. These sharks are believed to have been similar in appearance to the sand tiger shark.
	+ Genus †*Leptostyrax*
		- *Leptostyrax macrorhiza*

* Family Lamnidae
	+ Genus *Carcharodon-* A family containing three species, two of which are extinct. The only living representative of this family, the great white shark, is the largest predatory fish alive in the modern era.
		- *Carcharodon carcharias* (great white shark)
		- †*Carcharodon hubbelli*
		- †*Carcharodon caifassii*
	+ Genus †*Carchariolamna*
		- †*Carchariolamna heroni*
	+ Genus †*Carcharomodus*
		- †*Carcharomodus escheri*
	+ Genus †Isurolamna
		- †Isurolamna affinis
		- †Isurolamna bajarunasi
		- †Isurolamna gracilis
		- †Isurolamna inflata
	+ Genus †Lethenia
		- †Lethenia vandenbroecki
	+ Genus †Macrorhizodus
		- †Macrorhizodus americanus
		- †Macrorhizodus nolfi
	+ Genus *Isurus* (mako sharks)- A family of lamniformes most closely related to the genus *Carcharodon*, there two living species in this genus, the shortfin mako and the longfin mako. There are nine or ten extinct species within this genus (opinion is divided on the exact classification of the species Isurus hastalis, which may in fact belong to the genus *Carcharodon*, as it is theorized to be a direct ancestor of the great white shark.)
		- *Isurus oxyrinchus* (shortfin mako)
		- *Isurus paucus* (longfin mako)
		- †*Isurus desori*
		- †*Isurus escheri*
		- †*Isurus flandricus*
		- †*Isurus hastalis* (may belong to *Carcharodon* or *Cosmopolitodus*) †
		- †*Isurus minutus*
		- †*Isurus nakaminatoensis*
		- †*Isurus planus*
		- †*Isurus praecursor*
		- †*Isurus rameshi*
		- †*Isurus spallanzani*
	+ Genus *Lamna* (Porbeagle and salmon sharks)*-* The genus *Lamna* contains two living species; the salmon shark and the porbeagle, once thought to be the same species until research proved them to be distinct. An additional seven species are extinct.
		- *Lamna ditropis* (Salmon shark)
		- *Lamna nasus* (porbeagle)
		- †*Lamna attenuata*
		- †*Lamna carinata*
		- †*Lamna hectori*
		- †*Lamna marginalis*
		- †*Lamna quinquelateralis*
		- †*Lamna trigeri*
		- †*Lamna trigonata*

* Family Megachasmidae (Megamouth sharks)- A family containing only one genus and species. Little if anything is known of the origins of megamouths or their evolution. This shark is believed to be a deep-water vertical migrator that is confirmed to feed on zooplankton.
	+ Genus *Megachasma*
		- *Megachasma pelagios* (megamouth shark)

* Family Mitsukurinidae (goblin sharks)- Goblin sharks are a family of lamniformes that are elongated and have extended snouts for prey detection. the only living representative of the family is the goblin shark (*Mitsukirina owstoni*), a deepwater species that can grow to a maximum length of 20 feet. This family dates back to the late cretaceous.
	+ Genus *Mitsukurina*
		- *Mitsukurina owstoni* (goblin shark)
	+ Genus †Scapanorhynchus
	+ Genus †Anomotodon
	+ Genus †Protoscapanorhynchus
	+ Genus †Pseudoscapanorhynchus
	+ Genus †Woellsteinia

* Family Odontaspididae (Sand sharks)- Sand sharks are a family of lamniformes that contain three living species. The most common and best known, the sand tiger shark (*Carcharias taurus*) is a popular animal featured in aquariums. The smalltooth sand tiger and bigeye sand tiger (*Odontaspis ferox* and *Odontaspis noronhai*, respectively) are mid-to-deep water species that are poorly understood. Some extinct species, such as *Pseudomegachasma*, resembled the modern megamouth, being filter-feeders while others like *Striatolamia* were more similar to modern forms.
	+ Genus *Carcharias*
		- *Carcharias taurus* (sand tiger shark)
		- Genus *Odontaspis*
			* *Odontaspis ferox* (smalltooth sand tiger)
			* *Odontaspis noronhai* (bigeye sand tiger)
				+ Subfamily †Odontaspinae
				+ Genus †Striatolamia
					- †Striatolamia macrota
					- †Striatolamia striata
					- †Striatolamia whitei
				+ Genus †Carcharoides
				+ Genus †Parodontaspis
				+ Genus †Priodontaspis
				+ Genus †Pseudoisurus
				+ Genus †Synodontaspis
					- Subfamily †Johnlonginae
						* Genus †Johnlongia
						* Genus †*Pseudomegachasma*
							+ †*Pseudomegachasma casei*
							+ †*Pseudomegachasma comanchensis*

* Family Pseudocarchariidae (Crocodile sharks)- A family contains one genus and species. The crocodile shark is a small midwater species that is most closely related to the sand tiger sharks. It is a vertical migrator.
	+ Genus *Pseudocarcharias*
		- *Pseudocarcharias kamoharai*  (crocodile shark)

* Family †Cardabiodontidae- Cardabiodontidae is an extinct family of lamniformes dating back to the cretaceous period. Only one genus is currently known for this family; *Cardabiodon*. Fossils of this family are only known from Australia.
	+ Genus †Cardabiodon
		- †*Cardabiodon ricki*

* Family †Cretoxyrhinidae (Ginsu sharks)- The Cretoxyrhinidae is a family of extinct lamniform sharks containing three genera. These sharks are known from cretaceous to Eocene deposits.
	+ Genus †*Cretoxyrhina*
		- †*Cretoxyrhina mantelli* (ginsu shark)
	+ Genus †*Dallasiella*
	+ Genus †*Palaeocarcharodon*
		- †*Paleocarcharodon orientalis*
	+ Genus †*Paraisurus*
	+ Genus †*Plicatolamna*
	+ Genus †*Protolamna*
	+ Genus †*Serratolamna*
		- †*Serratolamna africana*
		- †*Serratolamna amonensis*
		- †*Serratolamna caraibaea*
		- †*Serratolamna gafsana*
		- †*Serratolamna khderii*
		- †*Serratolamna lerichei*
		- †*Serratolamna serrata*

* Family †Otodontidae (megatooth sharks) A family of extinct sharks containing the largest sharks known to science. Carcharocles megalodon, the largest species, was the largest known genus of shark. Many of the larger members of this family were specialist hunters of large sea mammals such as cetaceans.
	+ Genus †*Cretolamna*
		- †Cretolamna appendiculata
		- †Cretolamna aschersoni
		- †Cretolamna biauriculata
		- †Cretolamna lata
		- †Cretolamna maroccana
		- †Cretolamna pachyrhiza
		- †Cretolamna serrata
	+ Genus †*Otodus*
		- †*Otodus obliquus*
	+ Genus †*Megalolamna*
		- †*Megalolamna paradoxodon*
	+ Genus †*Carcharocles*
		- †*Carcharocles auriculatus*
		- †*Carcharocles angustidens*
		- †*Carcharocles chubutensis*
		- †Carcharocles sokolovi
		- †Carcharocles aksuaticus
		- †Carcharocles poseidoni
		- †*Carcharocles megalodon* (megatooth shark) (genus disputed)=

* Family †Pseudocoracidae
	+ Genus †Galeocorax
		- †*Galeocorax sp.*

* + Genus †Pseudocorax
		- †*Pseudocorax affinis*
		- †*Pseudocorax laevis*

## Conservation Status

Of the numerous living species of lamniform sharks, many are classified by the IUCN as being in threatened with extinction, and many species show decreasing population trends. Basking sharks, shortfin and longfin makos, great whites, two species of sand tigers, and three species of thresher sharks are classified as "Vulnerable", while the crocodile shark is classified as "Near Threatened". The Goblin Shark is the only living species within this order that is listed as "Least Concern". Bigeye sand tigers are classified as "Data Deficient" due to the rarity of sightings, general lack of information on this species, and the inaccessibility of their deepwater habitat.