Looks like a Caiman to me! Make sure you get permission to post images from other users, especially from other forums. Providing a link to the image is different than posting an image on someone's behalf without prior consent. As a photographer, I'm honored when people want to share my shots, but not when I find them spammed all over the place without me knowing about it!

http://farm8.staticflickr.com/7172/6...ff722968_z.jpg
Common Caiman from down in Panama this past November :-)