Caiman (genus)

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Caiman is a genus of caimans within the alligatorid subfamily Caimaninae. They inhabit Central and South America. They are relatively small sized crocodilians, with all species reaching lengths of only a couple of meters and weighing 6 to 40 kg (13 to 88 lb) on average.

Caiman
Temporal range: Middle MiocenePresent, 16–0 Ma[1]
Yacare caiman, Caiman yacare
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Clade: Archosauriformes
Order: Crocodilia
Family: Alligatoridae
Subfamily: Caimaninae
Clade: Jacarea
Genus: Caiman
Spix, 1825
Type species
Caiman crocodilus
Linnaeus, 1758
Subgroups

See text.

Synonyms
  • Jacaretinga Spix, 1825
  • Champsa Wagler, 1830
  • Jacare Gray, 1844

Classification

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The genus Caiman contains three extant (living) species: the Broad-snouted caiman ("Caiman latirostris"), the Spectacled caiman (Caiman crocodilus), and the Yacare caiman (Caiman yacare). There are also several extinct fossil species in the genus - possibly up to eight species. The genus Caiman belongs to the caiman subfamily Caimaninae, and the relationships of the living species of caimans can be shown in the cladogram below, based on molecular DNA-based phylogenetic studies:[2]

Alligatoridae
Caimaninae

Paleosuchus palpebrosus Cuvier's dwarf caiman

Paleosuchus trigonatus Schneider's dwarf caiman

Jacarea

Caiman crocodilus Spectacled caiman

Caiman yacare Yacare caiman

Caiman latirostris Broad-snouted caiman

Melanosuchus niger Black caiman

Alligatorinae

Alligator sinensis Chinese alligator

Alligator mississippiensis American alligator

The below detailed cladogram of Caimaninae includes extinct fossil species, based on morphological analysis:[3]

Characteristics

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Caimans are similar to alligators in morphology but differ in having bony plates, known as osteoderms, buried in the skin on the underside. The broad-snouted and spectacled caimans are characterised by having a bony ridge across the bridge of the nose just below the eyes.[4] The yacare caiman is the largest species in the genus, attaining an average adult length of 2.5 to 3 m (8.2 to 9.8 ft),[5] the spectacled caiman reaches 2 to 2.5 m (6.6 to 8.2 ft), with the female rather smaller,[6] and the broad-snouted caiman is the smallest, more typically measuring 1.8 to 2 m (5.9 to 6.6 ft) for males and 1.2 to 1.4 m (3.9 to 4.6 ft) for females.[7]

Distribution and habitat

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This genus is present in Central and South America. The spectacled caiman (Caiman crocodilus) occurs in Central America and parts of the northern half of South America at altitudes of up to about 800 m (2,600 ft). It is usually found in freshwater, but also visits the brackish water of estuaries on occasion. It has varying habitats including wetlands and slow-moving rivers and streams.[8] The yacare caiman (Caiman yacare) occurs in the central part of southern South America, particularly in the Pantanal region, the largest tropical wetland area in the world, which is flooded seasonally by the Paraguay River.[9] The broad-snouted caiman (Caiman latirostris) occurs in central and eastern South America, its range including southeastern Brazil, Bolivia, Paraguay, Uruguay and northern Argentina, within the drainage systems of the Paraná, Paraguay, Uruguay and São Francisco Rivers.[10]

Behaviour

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Caimans spend much of their time basking on mudflats or in sunlit, muddy jungle streams. In the dry season, large numbers may accumulate in pools as the surrounding land dries up. They can move on land with some rapidity, hiss when disturbed, and young individuals can inflate themselves before opening their jaws aggressively. Caimans do not usually attack humans but domestic livestock are at risk. They seize their prey and drag it underwater to drown it. They may observe a potential prey, swim away, submerge and return to attack the floating bird or drinking mammal from underwater. Juvenile caimans feed on crustaceans and molluscs while larger animals feed on amphibians, fish, birds, mammals and reptiles.[4]

A caiman nest is a mound of vegetation and mud consolidated by the female by lying on it. She then digs a hole in it and buries a few dozen eggs in it. When these hatch, the juveniles use their egg teeth to break their way out. They are about 23 cm (9 in) long at hatching, growing to 60 cm (24 in) by a year later. They look like miniature versions of their parents but have relatively shorter snouts and larger eyes.[4]

Taxonomy

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Extant species

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Image Scientific name Common name Distribution
  Caiman crocodilus Spectacled caiman Central and South America
  Caiman latirostris Broad-snouted caiman Brazil, northern Argentina, Uruguay, Paraguay, and Bolivia
  Caiman yacare Yacare caiman northeastern Argentina, Uruguay, southeastern Peru, eastern Bolivia, central/southwest Brazil, and the rivers of Paraguay

Fossil species

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Species known only from fossil remains:

Caiman venezuelensis from the Pleistocene epoch is probably a junior synonym of the spectacled caiman.[15] Some fossil taxa previously included within the genus Caiman now belong to separate extinct genera, including Acresuchus and Paranasuchus.[16][17]

References

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  1. ^ Rio, Jonathan P.; Mannion, Philip D. (6 September 2021). "Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem". PeerJ. 9: e12094. doi:10.7717/peerj.12094. PMC 8428266. PMID 34567843.
  2. ^ Bittencourt, Pedro Senna; Campos, Zilca; Muniz, Fabio de Lima; Marioni, Boris; Souza, Bruno Campos; Da Silveira, Ronis; de Thoisy, Benoit; Hrbek, Tomas; Farias, Izeni Pires (22 March 2019). "Evidence of cryptic lineages within a small South American crocodilian: the Schneider's dwarf caiman Paleosuchus trigonatus (Alligatoridae: Caimaninae)". PeerJ. 7: e6580. doi:10.7717/peerj.6580. PMC 6433001. PMID 30931177.
  3. ^ Cicade, G.M.; Fortier, D.; Hsiou, A.S. (2020). "Taxonomic and phylogenetic review of Necrosuchus ionensis (Alligatoroidea: Caimaninae) and the early evolution and radiation of caimanines". Zoological Journal of the Linnean Society. 189 (2): 657–669. doi:10.1093/zoolinnean/zlz051.
  4. ^ a b c Burton, Maurice; Burton, Robert (2002). International Wildlife Encyclopedia: Brown bear – cheetah. Marshall Cavendish. pp. 358–360. ISBN 978-0-7614-7269-8.
  5. ^ Briton, Adam. "Caiman yacare (Daudin, 1802)". Crocodilian species list. Retrieved 2015-09-09.
  6. ^ Briton, Adam. "Caiman crocodilus (Linnaeus, 1758)". Crocodilian species list. Archived from the original on 2015-10-22. Retrieved 2015-09-09.
  7. ^ Briton, Adam. "Caiman latirostris (Daudin, 1801)". Crocodilian species list. Retrieved 2015-09-09.
  8. ^ Terry, Kayla (2010). "Caiman crocodilus: Common caiman, spectacled caiman". Animal Diversity Web. University of Michigan. Retrieved 2015-09-08.
  9. ^ Smith, Roff (2013-07-01). "Yacare caiman: The Comeback Croc". National Geographic. Archived from the original on 2017-07-31. Retrieved 2015-09-08.
  10. ^ Verdade, Luciano M.; Larriera, Alejandro; Piña, Carlos I. "Broad-snouted Caiman: Caiman latirostris" (PDF). IUCN. Archived from the original (PDF) on 2016-03-08. Retrieved 2015-09-08.
  11. ^ Caiman australis at Fossilworks.org
  12. ^ Caiman brevirostris at Fossilworks.org
  13. ^ Caiman praecursor at Fossilworks.org
  14. ^ Rodolfo Salas-Gismondi; John J. Flynn; Patrice Baby; Julia V. Tejada-Lara; Frank P. Wesselingh; Pierre-Olivier Antoine (2015). "A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands". Proceedings of the Royal Society B: Biological Sciences. 282 (1804): 20142490. doi:10.1098/rspb.2014.2490. PMC 4375856. PMID 25716785.
  15. ^ Giovanne M. Cidade; Daniel Fortier; Ascanio Daniel Rincón; Annie Schmaltz Hsiou (2019). "Taxonomic review of two fossil crocodylians from the Cenozoic of South America and its implications for the crocodylian fauna of the continent". Zootaxa. 4656 (3): 475–486. doi:10.11646/zootaxa.4656.3.5. PMID 31716812. S2CID 202012442.
  16. ^ Souza-Filho, Jonas P.; Souza, Rafael G.; Hsiou, Annie Schmaltz; Riff, Douglas; Guilherme, Edson; Negri, Francisco Ricardo; Cidade, Giovanne M. (2018-09-03). "A new caimanine (Crocodylia, Alligatoroidea) species from the Solimões Formation of Brazil and the phylogeny of Caimaninae". Journal of Vertebrate Paleontology. 38 (5): e1528450. Bibcode:2018JVPal..38E8450S. doi:10.1080/02724634.2018.1528450. ISSN 0272-4634. S2CID 91964360.
  17. ^ Bona, P.; Barrios, F.; Ezcurra, M.D.; Victoria, M.; Blanco, F.; Cidade, G.M. (2024). "New taxa of giant caimans from the southernmost hyperdiverse wetlands of the South American late Miocene". Journal of Systematic Palaeontology. 22 (1). doi:10.1080/14772019.2024.2375027.