DOES seem to show the same kind of off-set position on a starfish! It IS one of the first things you notice about the disk when you look at it!
Its normal for the tube foot groove to have defense or other kinds of structures right on the edge of the "trench"
In some groups, we see more... pronounced structures that one might compare with the anti-fighter craft on the Death Star's surface..
Man the embattlements! Turbo lasers to the defense! Starfish don't QUITE have the anti-X-wing capabilities of the Death Star but what they DO have....
Its not QUITE clear what pedicelllariae do however. They look jaw or even clam-shaped, sometimes with numerous teeth on each piece.
These look more analogous to "turbo lasers" in that they are extended well off the surface of the starfish's body.