''Isistius'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of dogfish sharks in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Dalatiidae The Dalatiidae are the family of kitefin sharks of the order Squaliformes (the term "kitefin shark" also refers specifically to the species '' Dalatias licha''). Members of this family are small, under long, and are found worldwide. They have ci ...

. They are commonly known as cookiecutter sharks. Members of the genus are known for their unusual behaviour and dentition.

Species

*''Isistius brasiliensis'' Quoy &

Gaimard Joseph Paul Gaimard (31 January 1793 – 10 December 1858) was a French naval surgeon A naval surgeon, or less commonly ship's doctor, is the person responsible for the health of the ship's company aboard a warship. The term appears often ...

, 1824 ( cookiecutter shark) *''Isistius plutodus'' Garrick & S. Springer, 1964 ( largetooth cookiecutter shark) *†'' Isistius triangulus Probst, 1879 *†'' Isistius trituratus Winkler, 1876

Habits

The cookiecutter sharks, or cigar sharks, are unusual in the manner in which they replace their teeth. Instead of replacing teeth singly as they get damaged or lost, for example in hunting, such sharks replace the whole set. They can repeat such replacement throughout their lifetimes. Cookiecutter sharks often attack large shoals of fish, but have been known to circle fishing vessels to get an easy meal. They are particularly notorious for biting small chunks off of a prey animal in passing. Large prey, such as

swordfish Swordfish (''Xiphias gladius''), also known as broadbills in some countries, are large, highly migratory predatory fish characterized by a long, flat, pointed bill. They are a popular sport fish of the billfish category, though elusive. Swordfi ...

and

cetacean Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel them ...

s, may bear several healed wounds from such bites.Papastamatiou Yannis P., Wetherbee, Brad M., O'Sullivan, John, Goodmanlowe Gwen D. Lowe, Christopher G.; Foraging ecology of Cookiecutter Sharks (Isistius brasiliensis) on pelagic fishes in Hawaii, inferred from prey bite wounds.; Environmental Biology of Fishes, Volume 88, Number 4, 361-368, Weaker prey may be injured enough to be weakened until they are unable to swim properly. They then are prone to sinking, enabling these sharks to gorge. ''Isistius'' species can eat half of their own body weight at a time.

References

Extant Thanetian first appearances Shark genera Taxa named by Theodore Gill {{shark-stub

Species

Habits

See also

References