In 1988... I can't think of where these would have been exhibited. Possibly free-ranging on the lake, perhaps? (ps I don't expect you to remember Hix, more just wondering aloud)
I can barely remember Phoenix Zoo - we had about 2 hours to check out the whole place. I think these were on a smallish lake / largish pond that had a lemur island in the middle of it. There was a bridge nearby and I remember photographing some American White Pelicans and a rather large softshell turtle there too.
