Ha really? I thought you needed to pick up those items at the top and get the Ptyrodactyls to fight you to get the Tyrano out?!
No, you don't
have to fight the Pterodactyls; as Molotov already mentioned, you only have to win 6 battles.
I'm apologize for saying that you needed to get rid of so many denadorites. My memory was a bit faulty, as apparently the only monsters that actually drop denadorites are the Prehysterics.
and Selling materials? All I know is...
All I know is that any blacksmith or element shop screens, only have the option of selling either forged weapons/armors/accesorioes or acquired elements/consumables/traps, respectively.
So there is no way to get rid of them. At least not through selling them as materials.
oh... let me test this out for a minute. If I get the Tyrano, or sell materials (cause its annoying to find a treasure and have it tell you you have 99 Denadorites) I'll come back. Give me a minute.
As I said, you don't
have to fight the 3 pterodactyls. But it is convenient to do so, more so than three other monsters.
You can steal rare Stamina Belts (or Cloud Clapes regularly) from each of them, if you get lucky. To fight them, it isn't necessary to obtain the contents of each treasure chest. All you have to do is try to open them, and then they'll come right after you get the message that you can't carry any more of them. But I'm sure you probably already know that, by now.
Personally, I find it annoying to have to open the chests to be able to fight the Pterodactyls and I really dislike leaving any unopened treasure chests behind. This is why I suggested that to get rid of all the monsters (and get all the treasure chests), you would have to get rid of a large amount of denadorites (but the number is more like half of what I said).