Attention, fellow Gaiafen:
We have nekkid Gino! I repeat, we have NEKKID GINO!
ETA: Discussion of the leaked art led to mentions of the symbolism of nudity in magical-girl anime, which led to the expected conclusion.
Still, even if Gino is secretly a magical girl, that doesn't quite tell us why he's apparently getting raped in the face by a giant clam.