Caiman

Caimans Temporal range: Paleocene—Present, 60–0 Ma PreЄ Є O S D C P T J K Pg N
Yacare caiman, Caiman yacare
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	Crocodylomorpha
Order:	Crocodilia
Family:	Alligatoridae
Subfamily:	Caimaninae Brochu, 1999
Type species
Caiman latirostris Daudincrrefwad, 1825
Genera and Species
See below

A caiman is an alligatorid crocodilian belonging to the subfamily Caimaninae, one of two primary lineages within Alligatoridae, the other being alligators.

Description

Caimans inhabit Central and South America from marshes and swamps to mangrove rivers and lakes. As with other reptiles, caimans have scaly skin and live a fairly nocturnal existence.

They are relatively small sized crocodillians, with an average maximum weight of 6 to 40 kg (13 to 88 lb) depending on species, with the exception of the black caiman (Melanosuchus niger), which can grow more than 5 m (16 ft) in length and weigh up to 1,100 kg (2,400 lb). The black caiman is the largest caiman species in the world and is found in the slow-moving rivers and lakes that surround the Amazon basin. The smallest species is the Cuvier's dwarf caiman (Paleosuchus palpebrosus), which grows to 1.2 to 1.5 m (3.9 to 4.9 ft) long. There are six different species of caiman found throughout the watery, jungle habitats of Central and Southern America. The average length for most of the other caiman species if about 2 meters to 2.5 meters long.

Caimans are distinguished from alligators, their closest (and more widely known) relatives, by a few defining features: a lack of a bony septum between the nostrils, ventral armor composed of overlapping bony scutes formed from two parts united by a suture, and relatively longer, more slender teeth than those that alligators possess. Several extinct forms are known, including Purussaurus, a giant Miocene genus that grew to 12 m (39 ft) and the equally large Mourasuchus, which had a wide duck-like snout.^[1]

Behaviour

Spectacled caiman (Caiman crocodilus)

The caiman is a carnivorous predator and, like the alligator and the crocodile, the caiman has a diet that consists of a great deal of fish. The caiman also hunts insects, birds and small mammals and reptiles.

Due to the large size and ferocious nature of the caiman, it has few natural predators within its environment. Humans are the main predators of the caiman as they have been hunted for their meat and skin. Jaguars are the only other predator of the caiman.

Female caimans build a large nest in which to lay their eggs, which can be more than 1.5 meters wide. Female caimans lay between 10 and 50 eggs which hatch within about 6 weeks. Once they have hatched, the mother caiman takes her young to a shallow pool of water where they can learn how to hunt and swim.

Broad-snouted caiman (Caiman latirostris)

Yacare caiman (Caiman yacare)

Taxonomy

Black caiman (Melanosuchus niger)

Cuvier's dwarf caiman (Paleosuchus palpebrosus)

Smooth-fronted caiman (Paleosuchus trigonatus)

• Subfamily Caimaninae
  • Genus †Centenariosuchus
  • Genus †Culebrasuchus
  • Genus †Eocaiman
  • Genus †Globidentosuchus
  • Genus Paleosuchus
    • P. palpebrosus, Cuvier's dwarf caiman
    • P. trigonatus, smooth-fronted caiman
  • Genus †Purussaurus
  • Genus †Mourasuchus
  • Genus †Necrosuchus
  • Genus †Orthogenysuchus
  • Genus †Tsoabichi
  • Clade Jacarea
    • Genus Caiman
      • C. yacare, yacare caiman
      • C. crocodilus, spectacled caiman
        • C. c. apaporiensis, Rio Apaporis caiman
        • C. c. fuscus, brown caiman
      • †C. lutescens
      • †C. venezuelensis
      • C. latirostris, broad-snouted caiman
    • Genus Melanosuchus
      • †M. fisheri
      • M. niger, black caiman

Phylogeny

Below is a cladogram modified from Brochu (2011).^[2]

Alligatoridae	Alligatorinae  Caimaninae  †Eocaiman cavernensis †Necrosuchus ionensis †Tsoabichi greenriverensis Paleosuchus palpebrosus Paleosuchus trigonatus †Mourasuchus †Orthogenysuchus olseni †Purussaurus mirandai †Purussaurus neivensis  Jacarea  Caiman crocodilus Caiman yacare Caiman latirostris UCMP 39978 (referred to Caiman lutescens) †Melanosuchus fisheri Melanosuchus niger

Below is a cladogram modified from Hastings et al. (2013).^[3]

†Stangerochampsa mccabei †Brachychampsa montana †Brachychampsa sealeyi  Alligatoridae  Alligatorinae  Caimaninae  †Culebrasuchus mesoamericanus †Eocaiman cavernensis †Tsoabichi greenriverensis Paleosuchus palpebrosus Paleosuchus trigonatus †Centenariosuchus gilmorei †Purussaurus neivensis †Mourasuchus †Orthogenysuchus olseni Caiman crocodilus Caiman yacare Caiman latirostris †Caiman lutescens †Melanosuchus fisheri Melanosuchus niger

References

1. Brochu, C. A. (1999). "Phylogenetics, Taxonomy, and Historical Biogeography of Alligatoroidea". Society of Vertebrate Paleontology Memoir. 6: 9–100. doi:10.2307/3889340. JSTOR 3889340.
2. Brochu, C. A. (2011). "Phylogenetic relationships of Necrosuchus ionensis Simpson, 1937 and the early history of caimanines". Zoological Journal of the Linnean Society. 163: S228–S256. doi:10.1111/j.1096-3642.2011.00716.x.
3. Hastings, A. K.; Bloch, J. I.; Jaramillo, C. A.; Rincon, A. F.; MacFadden, B. J. (2013). "Systematics and biogeography of crocodylians from the Miocene of Panama". Journal of Vertebrate Paleontology. 33 (2): 239. doi:10.1080/02724634.2012.713814.