We've had conversations about the small keels that are barely visible on large adult make couperi. Every one I've seen has had it.
I kept a group of Texans before and they do not always, but do sometimes have them, especially the older, larger males.
That snake HAD to be a male, right? I've never seen them on females. One cool thing about couperi, you can sex an adult snakes shed skin, because you can actually see the keel marks on the shed!
Check out the keels on this Texan...




