Carcharodon carcharias, great white shark, Family Lamnidae, Tomiyama et. al., 1970
The Mackerel sharks (class Chondrichthyes , subclass Elasmobranchii ) have two dorsal fins without spines, and five gill slits. They usually have small spiracles behind the eyes. The mouth is large, and usually extends behind the eyes. There are seven families within the Lamniformes :
- Odontaspididae (sand tigers )
- Mitsukurinidae (goblin shark )
- Pseudocarchariidae (crocodile shark )
- Megachasmidae (megamouth shark )
- Alopiidae (thresher sharks )
- Cetorhinidae (basking shark )
- Lamnidae (mackerel sharks )
The Odontaspididae have an assymetrical caudal fin with a small lower lobe, and relatively small eyes. Up to 3.6 meters long, there are two genera and four species. All are marine in tropical and cool temperate waters in the Atlantic , Indian, and Pacific Oceans.
Odontaspis ferox, smalltooth sand tiger, family Odontaspididae, Unesco 1984a.
Mitsukurina owstoni, goblin shark,
family Mitsukurinidae, Unesco, 1984a.
This is the only species in the
Mitsukurinidae , and is immediately recognizable by its elongated and
flattened snout. Up to 3.3 meters long, it is found scattered throughout
the eastern and western Atlantic , off South Africa , and in the western
Pacific.
The Family Pseudocarchariidae , has only one species, the crocodile shark Pseudocarcharias
kamoharai, which reaches about 1.1 meter in length, and is found in
coastal and oceanic waters in the tropics and subtropics.
The family Megachasmidae also contains only one species, the recently
discovered (1976) "megamouth shark", Megachasma pelagios.
This large shark (up to 5.1 meters long) is a filter feeder. Only five
specimens have been collected , - off California , Hawaii , Western
Australia , and japan .
Family Alopiidae, the thresher sharks, contains three species all in the genus Alopias. Immediately recognizable by their elongated upper caudal lobe, they reach up to 5.5 meters in length. The long fin may be used to herd small fish together, making them easier prey, but this explanation has been questioned. Threshers are found in coastal and oceanic waters in the tropical to temperate regions of the Atlantic , Indian, and Pacific Oceans.
the family Cetorhinidae also contains only one species, the basking shark Cetorhinus maximus. Its large gill slits and fine gill rakers are adaptations to filter feeding on plankton . It is the second largest fish (behind the whale shark ), and is found in cool and warm temperate waters in both the southern and northern hemispheres . At least 10 meters in length, it is thought to perhaps reach 15.2 meters.
Cetorhinus maximus, the basking shark , family Cetorhinidae, Tomiyama et. al., 1970.
Isurus oxyrhincus, shortfin Mako shark, family Lamnidae, Unesco 1984a.
The family Lamnidae , or mackerel sharks , contains some of the species most dangerous to man, including the great white shark and the mako sharks . These sharks have relatively symmetrical caudal fins, and a strong lateral keel on their caudal peduncle . The great white, the largest species, reaches up to 6 meters in length. These fast pelagic sharks feed mostly on fish, although the great white shark frequently feeds on marine mammals . The shortfin mako , reaching approximately 3.8 meters in length, feeds on fish such as mackerel , sardines , tunas , and even swordfish . About five species in three genera are found in coastal and oceanic waters in the cool temperate to tropical areas of both northern and southern hemispheres .
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