Alligatoridae
Encyclopedia
Alligatoridae is a family
of crocodylians that includes alligator
s and caiman
s.
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) 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".
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 scute
s, 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.
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), 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.
s 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.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of crocodylians that includes alligator
Alligator
An alligator is a crocodilian in the genus Alligator of the family Alligatoridae. There are two extant alligator species: the American alligator and the Chinese alligator ....
s and caiman
Caiman
Caimans are alligatorid crocodylians within the subfamily Caimaninae. The group is one of two subfamilies of the family Alligatoridae, the other being alligators. Caimans inhabit Central and South America. They are relatively small crocodilians, with most species reaching lengths of only a few...
s.
True alligators
Alligators proper occur in the fluvial deposits of the age of the Upper ChalkCretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
in Europe, where they did not die out until the Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
age. The true alligators are now restricted to two species, A. mississippiensis
American Alligator
The American alligator , sometimes referred to colloquially as a gator, is a reptile endemic only to the Southeastern United States. It is one of the two living species of alligator, in the genus Alligator, within the family Alligatoridae...
in the southeastern United States
Southeastern United States
The Southeastern United States, colloquially referred to as the Southeast, is the eastern portion of the Southern United States. It is one of the most populous regions in the United States of America....
, which can grow to 4.24 m (14 ft) and weigh 1000 lbs (454.5 kg) and the small A. sinensis
Chinese Alligator
The Chinese alligator or Alligator Alligator sinensis) is one of two known living species of Alligator, a genus in the family Alligatoridae. The Chinese alligator is native only to China...
in the Yangtze River
Yangtze River
The Yangtze, Yangzi or Cháng Jiāng is the longest river in Asia, and the third-longest in the world. It flows for from the glaciers on the Tibetan Plateau in Qinghai eastward across southwest, central and eastern China before emptying into the East China Sea at Shanghai. It is also one of the...
, People's Republic of China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
, which grows to an average of 1.5 m (5 ft). Their name derives from the Spanish
Spanish language
Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...
el lagarto, which means "the lizard".
Caimans
In CentralCentral America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, the alligator family is represented by five species of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
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 scute
Scute
A scute or scutum is a bony external plate or scale, as on the shell of a turtle, the skin of crocodilians, the feet of some birds or the anterior portion of the mesonotum in insects.-Properties:...
s, 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.
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
Black Caiman
The black caiman is a crocodilian. It is a carnivorous reptile that lives along slow-moving rivers and lakes, in the seasonally flooded savannas of the Amazon basin, and in other freshwater habitats in South America. Once common, it was hunted to near extinction primarily for its commercially...
of the Amazon River
Amazon River
The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...
basin. Black Caimans grow to 16.5 feet (5 m), with the largest recorded size 5.79 m (19 ft). The black caiman and American Alligator
American Alligator
The American alligator , sometimes referred to colloquially as a gator, is a reptile endemic only to the Southeastern United States. It is one of the two living species of alligator, in the genus Alligator, within the family Alligatoridae...
are the only members of the alligator family that pose the same danger to humans as the larger species of the crocodile
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...
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
AlligatorAlligator
An alligator is a crocodilian in the genus Alligator of the family Alligatoridae. There are two extant alligator species: the American alligator and the Chinese alligator ....
s 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
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...
; 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.
Taxonomy
- ORDER CrocodiliaCrocodiliaCrocodilia is an order of large reptiles that appeared about 84 million years ago in the late Cretaceous Period . They are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria...
- Family Alligatoridae
- Genus LeidyosuchusLeidyosuchusLeidyosuchus is an extinct genus of alligatoroid from the Late Cretaceous of Alberta. It was named in 1907 by Lawrence Lambe, and the type species is L. canadensis. It is known from a number of specimens from the middle Campanian age Dinosaur Park Formation...
(extinct) - Genus DeinosuchusDeinosuchusDeinosuchus is an extinct genus related to the alligator that lived 73 to 80 Ma , during the late Cretaceous period. The name translates as "terrible crocodile" and is derived from the Greek deinos , "terrible", and soukhos , "crocodile"...
(extinct) - Subfamily Alligatorinae
- Genus AlbertochampsaAlbertochampsaAlbertochampsa is an extinct genus of globidontan alligatoroid from the Late Cretaceous of Alberta. It was named in 1972 by Bruce Erickson, and the type species is A. langstoni. It is known from a skull from the Campanian-age Dinosaur Park Formation, where it was rare; Leidyosuchus is the most...
(extinct) - Genus ChrysochampsaChrysochampsaChrysochampsa is an extinct genus of alligatorine. Fossils have been found from the Golden Valley Formation of North Dakota and date back to the Wasatchian regional North American faunal stage of the early Eocene...
(extinct) - Genus HassiacosuchusHassiacosuchusHassiacosuchus is an extinct genus of small alligatorid from the early Eocene of Germany, found at the Messel pit. It was named in 1935 by K. Weitzel, and the type species is H. haupti. A second species, H. kayi, was named in 1941 by C.C. Mook for material from the Bridgerian of Wyoming, but was...
(extinct) - Genus NavajosuchusNavajosuchusNavajosuchus is an extinct genus of alligatorine crocodylian. Its fossils have been found in the Paleocene-age Nacimiento Formation of the San Juan Basin, New Mexico . It was named in 1942 by Charles C. Mook, and the original type species was N. novomexicanus. N. novomexicanus was based on...
(extinct) - Genus CeratosuchusCeratosuchusCeratosuchus is an extinct genus of alligatorine from latest Paleocene rocks of Colorado's Piceance Basin and earliest Eocene rocks of Wyoming's Bighorn Basin in North America, a slice of time known as the Clarkforkian North American Land Mammal Age. Like its modern relatives, Ceratosuchus was a...
(extinct) - Genus AllognathosuchusAllognathosuchusAllognathosuchus is an extinct genus of alligatorine crocodylian with a complicated taxonomic history. This small alligatorine is known for its stout jaws and bulbous teeth, found near the rear of the tooth row in upper and lower jaws. These adaptations have historically been interpreted as...
(extinct) - Genus HispanochampsaHispanochampsaHispanochampsa is an extinct genus of alligatoroid crocodilian. More than 100 fossils dating back to the Oligocene have been found from Lleida, Spain. The genus was first named in 1936, and was initially thought to be an alligatorid...
(extinct) - Genus ArambourgiaArambourgiaArambourgia is an extinct genus of alligatorine crocodylian from Europe. It was named in 1905 and synonymized with Allognathosuchus haupti in 1990, but later reassigned as its own genus once again in 2004. It is thought to have been closely related to Hispanochampsa and Procaimanoidea...
(extinct) - Genus ProcaimanoideaProcaimanoideaProcaimanoidea is an extinct genus of alligatorid from the Eocene of North America. It was named posthumously in 1946 by Charles W. Gilmore; the type species is P. utahensis, from the Uintan of Utah. It is based on USNM 15996, a nearly complete skull and partial left hind leg. A second species,...
(extinct) - Genus WannaganosuchusWannaganosuchusWannaganosuchus is an extinct genus of small alligatorid...
(extinct) - Genus KrabisuchusKrabisuchusKrabisuchus is an extinct alligatorine which existed in what is now Thailand during the late Eocene. It was first named by paleontologists Jeremy A. Martin and Komsorn Lauprasert in 2010, and the type species is K. siamogallicus...
(extinct) - Genus AlligatorAlligatorAn alligator is a crocodilian in the genus Alligator of the family Alligatoridae. There are two extant alligator species: the American alligator and the Chinese alligator ....
- Alligator prenasalisAlligator prenasalisAlligator prenasalis is an extinct species of alligator. It is well known, with many fossils having been collected from the Oligocene Chadron and Brule Formations in South Dakota. The species was first named in 1904 but was originally classified as a crocodile in the genus Crocodilus. It was...
(extinct) - Alligator mcgrewi (extinct)
- Alligator olseni (extinct)
- Chinese AlligatorChinese AlligatorThe Chinese alligator or Alligator Alligator sinensis) is one of two known living species of Alligator, a genus in the family Alligatoridae. The Chinese alligator is native only to China...
, Alligator sinensis - EoalligatorEoalligatorEoalligator is an extinct genus of crocodilian which lived during the Paleocene. First described by Chinese paleontologist C.C. Young in 1964, two species have been named: Eoalligator chunyii and Eoalligator huiningensis.-External links:...
(extinct) - Alligator mefferdi (extinct)
- American AlligatorAmerican AlligatorThe American alligator , sometimes referred to colloquially as a gator, is a reptile endemic only to the Southeastern United States. It is one of the two living species of alligator, in the genus Alligator, within the family Alligatoridae...
, Alligator mississippiensis
- Alligator prenasalis
- Genus Albertochampsa
- Subfamily Caimaninae
- Genus NecrosuchusNecrosuchusNecrosuchus is an extinct genus of caiman from the Paleocene.-References:* A Pictorial Guide to Fossils by Gerard Ramon Case...
(extinct) - Genus EocaimanEocaimanEocaiman is an extinct genus of caiman from the Eocene of Argentina.-External links:* in the Paleobiology Database...
(extinct) - Genus PaleosuchusPaleosuchusPaleosuchus is a South American genus of reptile in the Alligatoridae family. They are the smallest members of the order Crocodilia in the Americas.The genus contains two species:* Cuvier's Dwarf Caiman ....
- Cuvier's Dwarf CaimanCuvier's Dwarf CaimanThe Cuvier's dwarf caiman or Musky caiman, Paleosuchus palpebrosus, is a relatively small crocodilian reptile from northern and central South America. It is found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Surinam and Venezuela...
, Paleosuchus palpebrosus - Smooth-fronted CaimanSmooth-fronted CaimanThe smooth-fronted caiman , also known as Schneider's smooth-fronted caiman, is a crocodilian reptile from South America...
, Paleosuchus trigonatus
- Cuvier's Dwarf Caiman
- Genus PurussaurusPurussaurusPurussaurus is an extinct genus of giant caiman that lived in South America during the Miocene epoch, 8 million years ago. It is known from skull material found in the Brazilian, Colombian and Peruvian Amazonia, and northern Venezuela. The estimated skull length for one large individual of the type...
(extinct) - Genus MourasuchusMourasuchusMourasuchus is an extinct genus of giant crocodilian from the Miocene of South America. It was similar in length and weight to Rhamphosuchus...
(extinct) - Genus OrthogenysuchusOrthogenysuchusOrthogenysuchus is an extinct genus of caimanine alligatorid. Fossils have been found from the Wasatch Beds of the Willwood Formation of Wyoming, deposited during the early Eocene. The type species is O. olseni. The holotype, known as AMNH 5178, is the only known specimen belonging to the genus...
(extinct) - Genus CaimanCaimanCaimans are alligatorid crocodylians within the subfamily Caimaninae. The group is one of two subfamilies of the family Alligatoridae, the other being alligators. Caimans inhabit Central and South America. They are relatively small crocodilians, with most species reaching lengths of only a few...
- Yacare CaimanYacare CaimanThe Yacare caiman is a species of caiman found in central South America, including northeastern Argentina, Uruguay eastern Bolivia, central/south-west Brazil, and the rivers of Paraguay...
, Caiman yacare - Spectacled CaimanSpectacled CaimanThe spectacled caiman , also known as the white caiman or common caiman, is a crocodilian reptile found in much of Central and South America. It lives in a range of lowland wetland and riverine habitat types and can tolerate salt water as well as fresh; due in part to this adaptability it is the...
, Caiman crocodilus- Rio Apaporis Caiman, C. c. apaporiensis
- Brown Caiman, C. c. fuscus
- Caiman lutescans (extinct)
- Caiman sorontans (extinct) - Not reported in the literature, probably a 'nomen nudumNomen nudumThe phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...
' - Broad-snouted CaimanBroad-snouted CaimanThe broad-snouted caiman is a crocodilian reptile found in eastern and central South America, including southeastern Brazil, northern Argentina, Uruguay, Paraguay and Bolivia. It is found mostly in freshwater marshes, swamps, and mangroves. Usually, in still or very slow moving waters...
, Caiman latirostris
- Yacare Caiman
- Genus Melanosuchus
- Melanosuchus fisheri (extinct)
- Black CaimanBlack CaimanThe black caiman is a crocodilian. It is a carnivorous reptile that lives along slow-moving rivers and lakes, in the seasonally flooded savannas of the Amazon basin, and in other freshwater habitats in South America. Once common, it was hunted to near extinction primarily for its commercially...
, Melanosuchus niger
- Genus Necrosuchus
- Genus Leidyosuchus
- Family Alligatoridae