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Alligatoridae

Cladus: Eukaryota
Supergroup: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Classis: Reptilia
Subclassis: Diapsida
Infraclassis: Archosauromorpha
Divisio: Archosauria
Subdivisio: Crurotarsi
Superordo: Crocodylomorpha
Ordo: Crocodilia
Subordo: Eusuchia
Familia: Alligatoridae
Subfamiliae: Alligatorinae - Caimaninae

Name

Alligatoridae Gray, 1844

Type genus: Alligator Cuvier, 1807

Reference

Cat. Tortoises Crocodiles Amphisbaenians Coll. Brit. Mus.: 56

Vernacular Names
Internationalization
Deutsch: Alligatoren
English: Alligators & Caimans
Hrvatski: Aligatori
Português: Jacaré

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Alligators and caimans are archosaurs, species of crocodilians and form the family Alligatoridae (sometimes regarded instead as the subfamily Alligatorinae).

True alligators

Alligators proper occur in the fluvial deposits of the age of the Upper Chalk in Europe, where they did not die out until the Pliocene age. The true alligators are now restricted to two species, A. mississippiensis in the southeastern United States, which can grow to 4.24 m (14 ft) and weigh 1000 lbs (454.5 kg)[1] and the small A. sinensis in the Yangtze River, People's Republic of China, which grows to an average of 1.5 m (5 ft). Their name derives from the Spanish el lagarto, which means "the lizard".
Alligator prenasalis fossil

Caimans

In Central and South America, the alligator family is represented by five species of the genus Caiman, which differs from the alligator by the absence of a bony septum between the nostrils, and the ventral armour is composed of overlapping bony scutes, each of which is formed of two parts united by a suture. Some authorities further divide this genus into three, splitting off the smooth-fronted caimans into a genus Paleosuchus and the Black Caiman into Melanosuchus. Caimans tend to be more agile and crocodile-like in their movements, and have longer, sharper teeth than alligators.[2]

C. crocodilus, the Spectacled Caiman, has the widest distribution, from southern Mexico to the northern half of Argentina, and grows to a modest size of about 2.2 meters. The largest is the near-threatened Melanosuchus niger, the Jacare-assu, Large, or Black Caiman of the Amazon River basin. Black Caimans grow to 16.5 feet (5 m),[3] with the largest recorded size 5.79 m (19 ft). The black caiman and American Alligator are the only members of the alligator family that pose the same danger to humans as the larger species of the crocodile family.

Although the Caiman has not been studied in-depth, scientists have learned that their mating cycles (previously thought to be spontaneous or year-round) are linked to the rainfall cycles and the river levels, which increases chances of survival for their offspring.

Differences from crocodiles
See also: Crocodilia#Differences between alligators and crocodiles

Alligators differ from crocodiles principally in having wider and shorter heads, with more obtuse snouts; in having the fourth, enlarged tooth of the under jaw received, not into an external notch, but into a pit formed for it within the upper one; in lacking a jagged fringe which appears on the hind legs and feet of the crocodile; in having the toes of the hind feet webbed not more than half way to the tips; and an intolerance to salinity, alligators strongly preferring fresh water, while crocodiles can tolerate salt water due to specialized glands for filtering out salt. In general, crocodiles tend to be more dangerous to humans than alligators. Another odd trait recently discovered is that both caimans and the American Alligator have been observed taking foliage and fruit into their diet in addition to their normal diet of fish and meat.[4]

Taxonomy[5]
An alligator nest at Everglades National Park, Florida, United States.

* ORDER Crocodilia
o Family Alligatoridae
+ Genus Leidyosuchus (extinct)
+ Genus Deinosuchus (extinct)
+ Subfamily Alligatorinae
# Genus Albertochampsa (extinct)
# Genus Chrysochampsa (extinct)
# Genus Hassiacosuchus (extinct)
# Genus Navajosuchus (extinct)
# Genus Ceratosuchus (extinct)
# Genus Allognathosuchus (extinct)
# Genus Hispanochampsa (extinct)
# Genus Arambourgia (extinct)
# Genus Procaimanoidea (extinct)
# Genus Wannaganosuchus (extinct)
# Genus Krabisuchus (extinct)
# Genus Alligator
* Alligator prenasalis (extinct)
* Alligator mcgrewi (extinct)
* Alligator olseni (extinct)
* Chinese Alligator, Alligator sinensis
* Alligator mefferdi (extinct)
* American Alligator, Alligator mississippiensis
+ Subfamily Caimaninae
# Genus Necrosuchus (extinct)
# Genus Eocaiman (extinct)
# Genus Paleosuchus
* Cuvier's Dwarf Caiman, Paleosuchus palpebrosus
* Smooth-fronted Caiman, Paleosuchus trigonatus
# Genus Purussaurus (extinct)
# Genus Mourasuchus (extinct)
# Genus Orthogenysuchus (extinct)
# Genus Caiman
* Yacare Caiman, Caiman yacare
* Spectacled Caiman, Caiman crocodilus
o Rio Apaporis Caiman, C. c. apaporiensis
o Brown Caiman, C. c. fuscus
* Caiman lutescans (extinct)
* Caiman sorontans (extinct) - Not reported in the literature, probably a 'nomen nudum'
* Broad-snouted Caiman, Caiman latirostris
# Genus Melanosuchus
* Melanosuchus fisheri (extinct)
* Black Caiman, Melanosuchus niger


References

1. ^ <http://www.eparks.org/marine_and_coastal/marine_wildlife/alligator.asp>
2. ^ Guggisberg, C.A.W. (1972). Crocodiles: Their Natural History, Folklore, and Conservation. p. 195. ISBN 0715352725.
3. ^ <http://www.flmnh.ufl.edu/cnhc/cbd-faq-q2.htm>
4. ^ <http://scienceblogs.com/tetrapodzoology/2008/10/alligators_eat_fruit.php>
5. ^ This list appears to be copied from: MobileReference The Illustrated Encyclopedia of North American Reptiles and Amphibians: An Essential Guide To Reptiles and Amphibians Of USA, Canada, and Mexico ISBN 1605014591, 2010

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