Yes, 'true tegus' like the argentine and the golden are in the in the genus
Tupinambis and this lizard is in
Callopistes, but both genera are in TEIIDAE, along with several other North and South American lizards.
http://www.embl-heidelberg.de/~uetz/...s/Teiidae.html has a list of members of the family TEIIDAE.
http://www.embl-heidelberg.de/~uetz/LivingReptiles.html is a great database whenever you want to check up on taxonomy.
Good Luck with your tegus.