Mangosteen

Several years ago, I listed this exotic fruit as mangosteen (Garcinia mangostana) but now I have my doubts. My gut feeling is that I got the genus right but not the species. I remember back then someone telling me that the seeds had been brought in by an air-taxi pilot from the southern Pará. Then too, I remember a visitor to the Bosque telling me that mangosteen is Queen Elizabeth's favorite fruit. I've been spreading the word ever since. One of the joys of being around tropical flora is that of learning the name of a plant, or in this case, the correct name. I sorted through pages of images on the net to find Garcinia xanthochymus, which for the world looks like the fruit in the attached image. But I won't jump to conclusions until I hear from the experts in the field of tropical fruits. In the meanwhile, I can report that the fruit is quite tasty but very acid. It's at its best as a juice.