When I got home and showed them to Barry, we quickly realized that they weren't limes. I was sick with a cold so didn't really feel like investigating at that time, so I stuck them into the refrigerator until I felt better. They kept well, and today, three days later, they still looked about the same as the day I bought them. I rinsed one off and decided to give it a try.
I still wasn't quite sure what I'd eaten, so I took the photo above and posted it on Facebook, asking if any of my San Pedro friends knew what it was. And not surprisingly, Rebecca (SanPedroScoop) quickly replied that it was a Golden Plum. She also said that I should eat it with salt and pepper. Salt and pepper?! I guess I shouldn't knock it until I've tried it, but I'm not so sure about that part. I promise to try it with my second one, though.
I did a little research online, but information on this fruit is not too easy to find. I found a photo of a tree seedling, Spondias spp, that is probably the tree that bears this fruit. This site also said they are called hogplums (maybe they are used as feed on farms?) and governors plums (I like that one better!) in addition to golden plums. And I found a photo of golden plums growing on a tree in Ceiba Jungle Camp on the mainland of Belize.
I guess it's a good thing that these little fruits turned out not to be limes. As with so many things here in Belize, the unfamiliar ends up turning into a new learning experience!