Who is this emperor?

[Statius]

Perhaps it's Gordian II, although the nose and furrowed brow does make him look a bit like the busts of Maximinus Thrax.

Agree with this and would lean towards the latter, although it's a softer image of Thrax than other busts I've seen.

Take on board the point people are making regarding is it even an Emperor. If it's not the likeness to several is quite striking.