Cryptic, Sympatric Diversity in Tegu Lizards of the Tupinambis teguixin Group (Squamata, Sauria, Teiidae) and the Description of Three New Species

The genus Tupinambis is distributed in South America east of the Andes, and currently contains four recognized species, three of which are found only in Brazil. However, the type species of the genus, T. teguixin, is known from a wide geographic range, including Bolivia, Brazil, Colombia, Ecuador, French Guyana, Guyana, Peru, Suriname, Trinidad and Tobago, and Venezuela. Molecular and morphological evidence indicate that T. teguixin is genetically divergent across its range and consists of four distinct clades, some of which are sympatric. The occurrence of cryptic sympatric species has exacerbated the nomenclatural problems of the past. The four members of the T. teguixin group continue to be confused with Salvator merianae, despite having a distinctly different morphology and reproductive mode. All members of the genus Tupinambis are classified as CITES Appendix II species, yet they continue to be heavily exploited, understudied, and confused in the minds of the public, conservationists, and scientists. Tegus are important in Neotropical ecosystems as predators, scavengers, and seed dispersal agents. They are hunted for skins and meat by thousands of indigenous and local people, and are an important source of protein and income. Between 1977 and 2006, there were 34 million tegu skins in trade, with the primary end product being cowboy boots. Tegus are habitat generalists, using forests, savannas, climbing trees, burrowing, and using riparian, mangrove, and human-modified habitats. Their populations must be substantial and resilient to sustain an annual harvest that averages 1.0-1.9 million individuals per year for thirty years. The genus Tupinambis contained seven species until Harvey et al. revalidated Salvator Duméril and Bibron for S. duseni, S. merianae, and S. rufescens. The generic split was subsequently supported by molecular work. Salvator inhabits much of South America east of the Andes, and shares a suite of traits distinguishing them from the sometimes sympatric Tupinambis. The four species, T. longilineus, T. palustris, T. quadrilineatus, and T. teguixin, remain in Daudin's genus. One of these, T. palustris, is poorly known and its status seems uncertain. Tupinambis teguixin is one of the largest terrestrial Neotropical lizards, with a maximum body length of 400 mm. Its systematic and nomenclature remain poorly resolved, with some authors describing the taxonomy as "tortuous." Genetic data indicate that the split among T. teguixin from Cuyabeno, Ecuador and Roraima, Brazil is comparable to differences between T. teguixin and T. longilineus and even to that between T. rufescens and T. merianae. This suggests that T. teguixin may be composed of multiple lineages.