How would you aspect the iguanas to look many years after the island flooded and food become harder to find

I would think that their body would have to adapt to the water, so the Iguanas would eventually turn into what we now know, an alligator or crocodile. But since the food may be harder to find, they probably will not have the same jaw structure (and teeth) as the ones we know of today. 

If you eat to much it could kill you.