I don't doubt that this is just an ancient counterfeiter's
hybrid of an
obv. of
Gordian III and a
rev. of
Julia Mamaea, but the coin made its way into
Cohen 79 (Kolb) as a normal issue, and was accordingly taken over by
RIC 128, though with a footnote that
Pink considered it false.
I suppose there may be numismatists tracking such pieces, possibly in the
hope that a solid silver specimen will turn up, proving that the
type is regular after all. A fruitless
search, I fear!
If someone can find the corresponding
aureus too, then the question would require reconsideration!