Been looking and doing some research into this coin. As I am still a bit new in the ancient coin game, I find myself going down some wrong directions. Most of the legend on this coin is not readable. I believe the obverse portrait to be Antonious Pius. The reverse I believe to be Selus with a serpent. It is about 24 mm in size. I do have some reference books and of course the internet, but seem to have hit a wall.
I'm far from an expert but it looks more like Commodus to me than Antonius Pius - I'm probably wrong fwiw. Unfortunately, I can't make out any of the letters.
Due to the coin's condition and images it's hard to say but I agree with Frogster-- it looks like Commodus, which means it could also be Marcus Aurelius, his daddy-- they look quite alike in their younger portraits. The reverse has me puzzled. It's a male standing right, holding a staff/scepter with a snake twining around. Serpent-entwined staff generally = Asklepios (Aesculapius for the Roman equivalent) but the hand-on-hip slightly leaned forward pose is typical of Herakles but it looks like the figures is wearing a garment draped on his lower body, so that isn't typical for Herakles. The reverse pose also reminds me of some depictions of Apollo. I quick trip through ACsearch.info didn't yield anything similar. Looks like a job for ISEGRIM but I still don't have the hang of searching that database. (@Ed Snible, can you help?) Asklepios seems like the best bet-- a Roman provincial issue.
Still no luck-- just more puzzles. Asklepios's father, Apollo Iatrus, is pictured on some coins leaning on a serpent-entwined staff, his other hand on his hip, but he is nude. Hmm. I'll search a little more tomorrow if no one else has come up with a likely match.
