Squaliformes is an
orderIn scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
of
sharkSharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s that includes about 97 species in seven families.
Members of the order have two
dorsal finA dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
s, which usually possess spines, no anal fin or
nictitating membraneThe nictitating membrane is a transparent or translucent third eyelid present in some animals that can be drawn across the eye for protection and to moisten it while maintaining visibility. Some reptiles, birds, and sharks have a full nictitating membrane; in many mammals, there is a small...
, and five
gill slitGill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of Cartilaginous fish such as sharks, rays, sawfish, and guitarfish. Most of these have five pairs, but a few species have 6 or 7 pairs...
s. In most other respects, however, they are quite variable in form and size. They are found worldwide, from polar to tropical waters, and from shallow coastal seas to the open ocean.
Classification
Family CentrophoridaeCentrophoridae are a family of squaliform sharks. The family contains just two genera and approximately 15 species. They are sometimes called gulper sharks but this is also the name of a specific species in the family, Centrophorus granulosus....
BleekerPieter Bleeker was a Dutch medical doctor and ichthyologist, famous for his work on the fishes of East Asia – Atlas Ichthyologique des Orientales Neerlandaises – which was published 1862–1877....
, 1859 (gulper sharks)
- Genus Centrophorus
Centrophorus is a genus of squaliform sharks. They are deep-water sharks found in temperate and tropical oceans throughout the world. They are characterized by grey or brown bodies, large green eyes, and spines on both dorsal fins...
- Genus Deania
Deania is a genus of long-snouted, deepwater dogfish sharks in the family Centrophoridae.-Species:* Deania calcea * Deania hystricosa * Deania profundorum Deania is a genus of long-snouted, deepwater dogfish sharks in the family Centrophoridae.-Species:* Deania calcea (R. T. Lowe, 1839) (Birdbeak...
Family DalatiidaeDalatiidae is a family of sharks in the order Squaliformes, commonly known as kitefin sharks . Members of this family are small, under long, and are found worldwide. They have cigar-shaped bodies with narrow heads and rounded snouts...
(J. E. GrayJohn Edward Gray, FRS was a British zoologist. He was the elder brother of George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray ....
, 1851) (kitefin sharks)
- Genus Euprotomicroides
- Genus Heteroscymnoides
- Genus Mollisquama
- Tribe Dalatiini
- Genus Dalatias
- Genus Isistius
Isistius is a genus of dogfish sharks in the family Dalatiidae. They are commonly known as cookiecutter sharks. Members of the genus are known for their unusual behaviour and dentition.-Species:...
- Tribe Euprotomicrini
- Genus Euprotomicrus
- Genus Squaliolus
Squaliolus is a genus of deep-sea dogfish sharks in the family Dalatiidae.-Species:* Squaliolus aliae Teng, 1959 * Squaliolus laticaudus H. M. Smith & Radcliffe, 1912...
Family Echinorhinidae GillTheodore Nicholas Gill was an American ichthyologist, mammalogist, malacologist and librarian.Born and educated in New York City under private tutors, Gill early showed interest in natural history. He was associated with J...
, 1862 (bramble sharks)
- Genus Echinorhinus
Echinorhinus is a genus of squaliform sharks, the only extant genus in the family Echinorhinidae. The name is from Greek echinos meaning "spiny" and rhinos meaning "nose". Both species are uncommon, little known sharks...
Family EtmopteridaeEtmopteridae is a family of sharks in the order Squaliformes, commonly known as lantern sharks. Their name comes from the presence of light-producing photophores on their bodies. The members of this family are small, under long, and are found in deep waters worldwide. There are 45 species in five...
FowlerHenry Weed Fowler was an American zoologist born in Holmesburg, Pennsylvania.He studied at Stanford University under David Starr Jordan...
, 1934 (lantern sharks)
- Genus Aculeola
- Genus Centroscyllium
Centroscyllium is a genus of big-eyed deepwater dogfishes with no anal fin, a grey or black-brown body, and dorsal spines, with the second one being much larger than the first. There are seven extant species.-Species:...
- Genus Etmopterus
Etmopterus, commonly known as lantern sharks, is a diverse genus of dogfish sharks in the family Etmopteridae. This genus has 35 described species.-Species:* Etmopterus baxteri...
- Genus Miroscyllium
- Genus Trigonognathus
Family Oxynotidae GillTheodore Nicholas Gill was an American ichthyologist, mammalogist, malacologist and librarian.Born and educated in New York City under private tutors, Gill early showed interest in natural history. He was associated with J...
, 1872 (rough sharks)
- Genus Oxynotus
Oxynotus is a genus of sharks in the order Squaliformes, commonly known as the rough sharks. It is the only extant genus in the family Oxynotidae. They live in deep waters in the Atlantic and western Pacific oceans....
Family SomniosidaeSomniosidae is a family of sharks in the order Squaliformes, commonly known as sleeper sharks.-Genera:* Centroscymnus Barbosa du Bocage & Brito Capello, 1864...
D. S. JordanDavid Starr Jordan, Ph.D., LL.D. was a leading eugenicist, ichthyologist, educator and peace activist. He was president of Indiana University and Stanford University.-Early life and education:...
, 1888 (sleeper sharks)
- Genus Centroscymnus
Centroscymnus is a genus of squaliform sleeper sharks in the family Somniosidae.-Species:* Centroscymnus coelolepis...
- Genus Centroselachus
- Genus Proscymnodon
Proscymnodon is a genus of fish in the Somniosidae family.It contains the following species:* Proscymnodon macracanthus * Proscymnodon plunketi...
- Genus Scymnodalatias
Scymnodalatias is a genus of squaliform sharks in the family Somniosidae.-Species:* Scymnodalatias albicauda Taniuchi & Garrick, 1986 * Scymnodalatias garricki Kukuyev & Konovalenko, 1988...
- Genus Scymnodon
Scymnodon is a genus of squaliform sharks in the family Somniosidae.-Species:** Scymnodon obscurus ** Scymnodon ringens Barbosa du Bocage & Brito Capello, 1864...
- Genus Somniosus
Somniosus is a genus of dogfish sharks in the family Somniosidae.-Species:* Somniosus microcephalus * Somniosus pacificus Bigelow & Schroeder, 1944...
- Genus Zameus
Zameus is a genus of dogfish shark in the family Somniosidae, containing two species.-Species:* Zameus ichiharai * Zameus squamulosus...
Family SqualidaeSqualidae is the family of dogfish sharks. They are found in the Atlantic, Pacific, and Indian oceans, from tropical equatorial climates to the Arctic and Antarctic....
BlainvilleHenri Marie Ducrotay de Blainville was a French zoologist and anatomist.Blainville was born at Arques, near Dieppe. In about 1796 he went to Paris to study painting, but he ultimately devoted himself to natural history, and attracted the attention of Georges Cuvier, for whom he occasionally...
, 1816 (dogfish sharks)
- Genus Cirrhigaleus
Cirrhigaleus is a genus of squaliform sharks in the family Squalidae.-Species:* Cirrhigaleus asper * Cirrhigaleus australis W. T. White, Last & Stevens, 2007...
- Genus Squalus
Further reading
- FAO Species catalogue Volume 4 Parts 1 and 2