The screwcork gildestia split from its ancestor the gildestia in Mason Polar Coast. They have evolved sharp "blades" on their underside to help them with their new lifestyle. They live in the shallows using their "blades" in a corkscrew-like motion to bore into the sand, hence their name. They then absorb the minerals from the sand they kicked up which, along with photosynthesis gives them additional energy which allows them to thrive. They have evolved a mild toxin to try to deter predators which gives them their reddish tint. Other than that they are the same as their ancestors.
Image edits: Nergali