Found on the ground in the forest near Sumaco National Park, Ecuador. Probably fell unripe, as it was hard and there were no other fruits like this on the ground in the area. Anyone have any ideas what it could be?

EDIT: I have inquired about the inside of the fruit, and even as the outside was still green and hard, the inside was reportedly brown and mushy with no distinguishing features.

EDIT again: Upon further inquiry, I have found out that the inside looked more like solid segments than the goop of a passionfruit.