The attached paper present morphological data of some species of Dixus, including some previosily reported in Iran. Despite there are no taxonomic keys, maybe the data can be useful to you for a comparison with your specimens.
I recommend you an old, but relatively good and complete key by Edmund Reiter on West palaearctic Harpalini. However it is in German. I used it for species from the former Soviet Central Asian desert with good results. Consult also the papers on collection of prof Povolny from Afganistan to check the occuring species