Lizard type (6)
(Other definitions for iguana that I've seen before include "Tropical tree-lizard" , "Large tree-climbing specimen of 5 down in tropical America" , "Arboreal lizard of S America" , "Type of lizard" , "Lizard Darwin found in the Galapagos" .)
'lizard type' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for gecko that I've seen before include "Wall Street character" , "Lizard than can't blink" , "Small lizard with adhesive foot-pads" , "Lizard with adhesive toes" , "Cold-blooded type" .)
(Other definitions for chameleon that I've seen before include "Small lizard able to change colour" , "Colour-changing lizard" , "person who's changeable" , "colour changer" , "Lizard able to change its skin colour" .)