Tupinambis is a lizard genus which belongs to the family Teiidae, and contains seven described species. These large lizards are commonly referred to as tegus (teiús in Portuguese); T. merianae (Argentine Black and White Tegu), T. rufescens (Red Tegu), and T. teguixin (Gold Tegu) are all common in the pet trade. They are primarily found in South America, although T. teguixin also occurs in Panama. Tegus that have escaped or have been illegally released have adapted to life in the wild in some of the more remote areas of South Florida.
Tegus are large reptiles, with some species reaching a total length of around four feet, and a weight of approximately fifteen pounds. These opportunistic, wide-ranging lizards can be found in a variety of habitats, from swamps to rainforests to savannahs and cities. Although terrestrial, they are capable swimmers, able to remain submerged for up to 22 minutes and having even been caught in gill nets set at sea. The dentition is serrated in the front and becomes more blunt towards the back of the mouth, indicating a generalist diet. Biomechanical studies have shown that Tegus have stronger limb bones than comparably-sized mammals or birds, a trait that may be inherent to amphibians and non-avian reptiles. They exhibit social and maternal behaviour; female Tegus construct burrows to lay their eggs in, and will protect their brood until they hatch. Up to 35 eggs are produced in a clutch. Tegus will hibernate together in groups, though males exhibit territorial behavior towards each other. Tegus are sexually dimorphic, with males growing larger than females and developing prominent "jowls" along the base of the lower jaw.
Tegus are omnivorous, foraging for a wide range of foods using their forked tongues, including fruit, fungi, various arthropods, small vertebrates, carrion, and eggs. The amount of meat that is consumed by tegus decreases as the animals mature. As adults, tegus have few predators. Among them are big cats, birds of prey and large snakes. Tegus defend themselves using their powerful jaws, which can exert forces of up to 1000N. A bite from an adult tegu can crush human fingers. 
Tegus fill the same ecological niche in South America that monitor lizards do in Africa, Asia and Australia, and are an example of convergent evolution. Though similar in appearance to monitors, tegus are not closely related and can be distinguished by their larger heads, shorter necks, heavier bodies and different arrangement of the scales on the body and tail. In addition, tegus can run on their hind legs like a Collared Lizard, while monitors are quadrupedal.
Economic importance and environmental impact
Tegus are among the most commercially exploited reptiles in the world. Up to 1,000,000 are harvested annually in their native Argentina for their hide and meat, and are particularly important as a source of income in rural or indigenous communities. Tegus can be also be found in captivity, where they are bred for the pet trade. They are reported to be highly intelligent, becoming docile as they mature and in some cases even ignoring food in favor of social interaction. However, tegus have demanding husbandry requirements due to their large size.
Within their native range, tegus are often thought of as pests, sometimes raiding chicken coops to feed on the eggs or fowl. They are noted predators of ground nesting bird and crocodilian eggs, and in some areas 80% of Spectacled Caiman nests are destroyed by tegus.  In South Florida, they have become an invasive species, and prey on the eggs of American Alligators instead. Predation by feral tegus may pose a threat to Florida's endangered wildlife, such as the Key Largo woodrat and the American Crocodile. On account of their fruit eating habits, tegus may serve an important ecological function by dispersing seeds through their droppings.
Taxonomy and Evolution
Species listed alphabetically.
- Tupinambis duseni Lönnberg, 1896 – Yellow Tegu
- Tupinambis longilineus Avila-Pires, 1995 – Rondônia Tegu
- Tupinambis merianae (Duméril & Bibron, 1839) – Black and White Tegu (formerly T. teguixin)
- Tupinambis palustris Manzani & Abe, 2002 Swamp Tegu
- Tupinambis quadrilineatus Manzani & Abe, 1997 – Four-striped Tegu
- Tupinambis rufescens (Günther, 1871) – Red Tegu - Günther 1871
- Tupinambis teguixin (Linnaeus, 1758) – Gold Tegu (formerly T. nigropunctatus)
Mitochondrial DNA analysis indicates a deep divergence between a northern clade (containing T. teguixin, T. longilineus, T. palustris and T. quadrilineatus) and a southern clade (containing T. merianae, T. rufescens and T. duseni.). The northern and southern clades are morphologically distinct, with the northern clade possessing a single pair of loreal scales between the eye and the nostril and a smooth texture to the scales on the body, and the southern clade possessing two pairs of loreal scales and a bumpy texture to the scales on the body. At least one recent review of the morphology of the Teiidae family has placed the tegus of the southern clade in the genus Salvator. Subsequent studies support the paraphyletic status of Tupinambis, though further research will be necessary to determine if the split will gain wider acceptance among the herpetological community. Comparative analysis of hemipene anatomy also provides support for the split between Tupinambis and Salvator. Tegus probably originated sometime during the Cenozoic era. Tupinambis fossils from Argentina date back to the late-Miocene period. Fossils of the extinct tegu Paradracaena can be found in earlier Miocene deposits.
As with many other animals from tropical South America (e.g. the Cariamae), the Tupinambis owes its scientific name to the pioneering accounts given by Piso & Marcgrave in their Historia Naturalis Brasiliae (1648). There was, however, a misinterpretation (by Linnaeus) of the Latin text, which reads "TEIVGVACV [...] Tupinambis", 'to the Tupinambá [Indians] TEIVGVACU'. Tupinambis was merely a metalinguistic term meaning 'to/for the Tupinambá,' whereas the intended, indigenous name for the animal was teiú-guaçú [lizard-big], lit. 'big lizard'.
- K. Megan Sheffield, Michael T. Butcher, S. Katharine Shugart, Jennifer C. Gander, and Richard W. Blob. "Locomotor loading mechanics in the hindlimbs of tegu lizards (Tupinambis merianae): Comparative and evolutionary implications" The Journal of Experimental Biology 214 (2011): 2616-2630
- Kiefer, Mara Cíntia; Ivan Sazima (2002). "Diet of juvnile tegu lizard Tupinambis merianae (Teiidae) in southeastern Brazil". Amphibia-Reptilia 23: 105–108. Retrieved 24 October 2011.
- Aggressive Behavior and Performance in the Tegu Lizard Tupinambis merianae: Anthony Herrel, Denis V. Andrade, José Eduardo de Carvalho, Ananda Brito, Augusto Abe, and Carlos Navas - Physiological and Biochemical Zoology Vol. 82, No. 6 (November/December 2009), pp. 680-685
- Monitors and Tegus, R. D. Bartlett and Patricia P. Bartlett
- 1.Activity and Ranging Behavior of the Red Tegu Lizard Tupinambis rufescens in the Bolivian Chaco - Rossy R. Montaño, Rosa Leny Cuéllar, Lee A. Fitzgerald, Florencio Mendoza, Filemón Soria, Christine V. Fiorello, Sharon L. Deem, and Andrew J. Noss - South American Journal of Herpetology 2013 8 (2), 81-88 http://www.bioone.org/doi/abs/10.2994/SAJH-D-13-00016.1
- Guide to Lizards, Robert G. Sprackland, Ph.D.
- Tupinambis, The Reptile Database
- Fitzgerald et all. 1999
- Harvey MB, Ugueto GN, Gutberlet RL: Review of teiid morphology with a revised taxonomy and phylogeny of the Teiidae (Lepidosauria: Squamata). Zootaxa 2012, 3459:1-156. http://www.mapress.com/zootaxa/2012/f/z03459p156f.pdf
- Pyron, R. A., Burbrink, F. T., & Wiens, J. J. (2013). A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes. BMC evolutionary biology, 13(1), 93
- da Silva M, Filho G, Cronemberger Á, Carvalho L, Manzani P, Vieira J (2013) Description of the hemipenial morphology of Tupinambis quadrilineatus Manzani and Abe, 1997 (Squamata, Teiidae) and new records from Piauí, Brazil. ZooKeys 361: 61-72. doi: 10.3897/zookeys.361.5738
- Tupinambis Remains from the Late Miocene of Argentina and a Review of the South American Miocene Teiids: Adriana M. Albino, Santiago Brizuela, and Claudia I. Montalvo, Journal of Herpetology 2006 40 (2), 206-213
- Pujos, F.; Albino, A.M.; Baby, P. & Guyot, J.L. 2009. Presence of the extinct lizard Paradracaena (Teiidae) in the Middle Miocene of the Peruvian Amazon. Journal of Vertebrate Paleontology, 29(2):594-598.
- Cf. 'Etnolingüística' discussion list; 2/22/2012; http://lista.etnolinguistica.org/3167
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