Alligatoridae

Source: Wikipedia, the free encyclopedia.

Alligatoridae
Temporal range:
Ma
American alligator (Alligator mississippiensis)
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Clade: Archosauriformes
Order: Crocodilia
Clade: Globidonta
Family: Alligatoridae
Gray, 1844
Subfamilies

The

crocodylians includes alligators, caimans
and their extinct relatives.

Phylogeny

A. olseni fore limb
Alligator prenasalis fossil

The superfamily

gavialids. When considering only living taxa (neontology
), this makes Alligatoroidea and Alligatoridae redundant.

The simplified

extant (living) crocodilians.[3][4][5]

Crocodylia
Alligatoroidea

Leidyosuchus

Diplocynodontinae

Diplocynodon

Globidonta

extinct basal Alligatoroid Globidontans

Alligatoridae
Caimaninae

Caiman

Melanosuchus

Paleosuchus

(
stem-based group
)
Alligatorinae

Alligator

(
stem-based group
)
(crown group)
(
stem-based group
)
(
stem-based group
)

extinct basal Crocodilians (possibly including Mekosuchinae)

Longirostres
Crocodyloidea

extinct basal crocodiles

Crocodylidae (crown group)

(
stem-based group
)
Gavialoidea

extinct basal Gavialoids

Gavialidae

Gavialis

Tomistoma

(crown group)
(
stem-based group
)
(crown group)
(crown group)

The below detailed cladogram shows one proposal for the internal relationships within Alligatoridae[6] (although the exact alligatoroid phylogeny is still disputed).

Alligatoroidea

Leidyosuchus

Diplocynodon

Alligatoridae
Alligatorinae

Ceratosuchus

Allognathosuchus

Navajosuchus

Arambourgia

Procaimanoidea

Wannaganosuchus

Alligator prenasalis

Alligator mcgrewi

Alligator olseni

Alligator sinensis Chinese alligator

Culebrasuchus

Alligator mississippiensis American alligator

Alligator mefferdi

Alligator thomsoni

(
stem-based group
)
Caimaninae

Stangerochampsa

Albertochampsa

Brachychampsa

Protocaiman

Gnatusuchus

Globidentosuchus

Eocaiman

Notocaiman

Kuttanacaiman

Purussaurus

Mourasuchus

Necrosuchus

Tsoabichi

Paleosuchus trigonatus Smooth-fronted caiman

Paleosuchus palpebrosus Cuvier's dwarf caiman

Centenariosuchus

Caiman latirostris Broad-snouted caiman

Melanosuchus niger Black caiman

Caiman yacare Yacare caiman

Caiman crocodilus Spectacled caiman

Caiman brevirostris

La Venta Caiman

Caiman wannlangstoni

(
stem-based group
)
(crown group)
(
stem-based group
)

Evolution

The superfamily

mitochondrial genome was sequenced in the 1990s.[10] The full genome, published in 2014, suggests that the alligator evolved much more slowly than mammals and birds.[11]

True alligators

The lineage including alligators proper (

Yangtze River, China, which grows to an average of 5 ft (1.5 m). Their name derives from the Spanish
el lagarto, which means "the lizard".

Caimans

in 2010

In

Caimaninae, which differ from the alligator by the absence of a bony septum between the nostrils, and having ventral armour composed of overlapping bony scutes, each of which is formed of two parts united by a suture. Besides the three species in Caiman, the smooth-fronted caimans in genus Paleosuchus and the black caiman in Melanosuchus are described. Caimans tend to be more agile and crocodile-like in their movements, and have longer, sharper teeth than alligators.[13]

C. crocodilus, the

near-threatened Melanosuchus niger, the jacaré-açu or large or black caiman of the Amazon River basin. Black caimans grow to 4.4 m (14.5 ft), with the unverified size of up to 5.7 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 caimans have not been studied in depth, scientists have learned 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.

Taxonomy

† = extinct

An alligator nest at Everglades National Park, Florida, United States
Spectacled caiman head
Black caiman, Jauaperi River, Amazonia
Head of smooth-fronted caiman

References

  1. ^ Family Alligatoridae (Alligators and Caiman) Archived 2016-03-04 at the Wayback Machine University of Bristol. Quote:"The Alligatoridae appears in the Upper Cretaceous while the genus Alligator first occurs in the Oligocene."
  2. doi:10.1146/annurev.earth.31.100901.141308. Archived (PDF) from the original on 2022-10-09.[permanent dead link
    ]
  3. ^ .
  4. .
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  6. .
  7. ^ .
  8. ^ .
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  12. ^ "American alligator". animals.nationalgeographic.com. National Geographic Society.
  13. .
  14. .

External links