Paul Marsh, aka Other Paul,  has suggested additions to the Parthian list.  The Militia are ex-hellenistic settlers and count as Special Troops; the Elymaians are vassals of the Parthian empire.

The appropriate lines of the list are:

No Base Type Ord Exp Wgt Str Weapons Pts
0-1 Elymaians OO Av MI 10 BO 22
0-1 Militia OO Lvy MI 8 HS, LS, SH 22
  • Elymaians may be downgraded to Ally status at a cost of -5 points per base.