Your coin has all the hallmarks of having been engraved
's engraver C as identified in his
classic die study [Sellwood
, D. 1976. The Drachms of the Parthian
"Dark Age". Journal of the Royal Asiatic Society, 1976 (1): 2-25.].
He generally characterizes engraver C's reverse style
in correct proportion but tending to jut forward. Bashlik
cheekflap runs down parallel to upper arm
, often reaching to elbow. Single diadem end converging with bashlik
neckflap above throne. Arm
definitely crooked at elbow on early issues but tending to become straight and horizontal with later ones. Sleeve ends in horizontal bar
and extends almost to ground. Left thigh curves towards knee, and leg
set back at 45°. Boot lace ends exaggerated and divergent. Throne back finishes at shoulder level or higher. Throne legs have three or four bulbs of even size, irregularly spaced. Ground line under archer's feet only and slopes markedly upwards to right. Omicron is small on early issues and pellet-shaped on later ones."
And specifically for the Type
33 drachms Sellwood
adds: "Engraver C consistently mis-spells ΘΕΟΠΑΤΟΡΟΣ as ΘΕΟΠΑΤΡΟΥ." Your coin does indeed read ΘΕΟΠΑΤΡΟΥ.Sellwood
claims that engraver C was involved in engraving examples of Types
26, 27, 28, 29, 33, 31, and 34 drachms.
I can email you Sellwood
's paper if you don't have access to it.