This is what is probably a fine specimen of Zygoneura sp. This ID is based on the asymmetric fork of the M vein, and on the lack of a distinct subtriangular patch of stout setae at the preapical end of the fore tibiae. As far as the last criterion goes, I reckon that this picture is highly inconclusive, and sadly, the closeups I attempted turn out way too blurry to be helpful.

Were this merry folk a male, the antennae would separate it from genus Metangela right away, but sadly, this is the lone representative of this species I have found (so far) in my samples.