it doesn't matter. musculature and skeletal function dictate that an alligator sweep the tail left and right in order to move through water. this looks akin to a dolphin fin... had it been a shark-oriented fin, that would be another story as it would be actually usable. the manner in which this is oriented, it would only be a detriment to locomotion and survival as compared to a non-deformed variant provided the normal musculature and skeleton of an alligator. as such, it wouldn't make sense to be a natural progression from OR to. if it's not a Photoshop, it's highly likely just a random deformity due to these observations. (ref lobsterboy)