There are seven recognized species of Tupinambis (tegu). Here are the scientific/latin names for each.

Tupinambis merianae
Tupinambis teguixin
Tupinambis rufescens
Tupinambis quadrilineatus
Tupinambis palustris
Tupinambis duseni
Tupinambis longilineus

The common names of these tegu are varied, there is no governing body in charge of assigning common names so one species can often have several common names. This causes a bit of confusion, but for some facts read THIS.

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Kingdom: Animalia,
Phylum: Chordata,
Class: Reptilia,
Order: Squamata,
Family: Teiidae,
Genus: Tupinambis