Back in the 60s Floridahad a program to distribute some popular varieties at the time. variety banks were placed in many countries, some are still being maintained others have been abandoned. from these trees, some commercial operations were set up, Haden, Palmer, Irwin, Kent , Osteen, Glenn, and even some Asian varieties. I am certain that many over the years locals have just planted mono embryonic seeds and have gotten new hybrids that might have some resemblance to known cultivars.
here is a video of one of these genoplasm banks set up during that program in Peru, The one in the DR was abandoned years ago, some of the trees were cut down, but many still are there, last year most these trees were heavily pruned with the Idea of turning this into a public fruit park, I have been assisting in ID'ing some of the varieties.
Anyway, the fruit you mention could be one of these or just a seedling hybrid.
http://youtu.be/NcW0udw2H3I