Hard to tell, I have both, but the leaf petioles are shorter on the Dwarf, maybe a little more open, about twice as long on a tall as a pup, and closed even when small, but they are both kinda stocky when small if separated from the mother and grown in a pot in good light. If the pups are left attached to a full size Tall Orinoco in an under story environment, they grow tall, very quickly, in pots not so much. I have some attached pups that are 4 feet tall (leaves included) with just a few true leaves, barely past the sword stage, if they were in pots at that height, they would be more leafed out resembling an adult. If it starts pupping while its pstem is short, then its probably a Dwarf, my tall dont pup until they get at least 5 1/2 or 6 feet of stem, and then only maybe one per year in my cooler environment, at ten feet I might get 2 or 3 pups before having to dig them for storage. I am guessing it is a dwarf as tall is less common, and the petioles are shorter on yours, here is a photo of one of my tall and dwarf side by side at roughly the same height. Note the longer leaf petioles on the tall on the left, as compared to the right. My tall also bloomed at 10 feet of pstem which I read is about the right size, a dwarf should bloom smaller. You might rather would have the dwarf if you have to dig and store, the tall pstems get 100+ pounds and digging them and carrying them around is a bit rough on the back. The tall also get close to 20 feet with leaves in my zone 7.