Are there any Yacare Caiman in the United States? The only one I could find was in Connecticut's Beardsley zoo, and St.Augustine does not list them, possibly because even though they claim to have every caiman, the Yacare was disputed at one point, but not anymore I believe. I find it hard to believe they are only in one connecticut zoo.
St. Augustine certainly had them on show (and labelled as yacare) when I was there in 2013; a lot could have happened in seven years though.
According to the crocodilians thread, there's 4 places - Beardsley and St Augustine, plus Alligator Adventure and Reptile Lagoon, both in South Carolina. Crocodilians in American Zoos
St. Augustine’s whole reputation is staked on one thing: their claim to having the only 100% complete collection of living crocodilians in the world, so of course they have them. Not to say it’s not a great facility, but you can bet that if any new subspecies of any croc/gator/caiman/gharial are ever officially recognized or identified, they would be the first to add them to their park.