Looks to me like he's mature....
Now for the hard part... What to do with them.
{pun?}
I was thinking he might be mature. Odd thing is, this guy is about 5.5" diameter! I bought him last fall at around 4" diameter and the claspers were tiny then, as big as you would expect for a young ray. THis spring, he really "sprouted". I wonder if being in the presence of a mature female sped up the process?