Draped bust and Δ

ARABIA PETRAEA. Petra. Septimius Severus. Æ 23. A.D. 193-211. Obv: (..)KMAV(...) or similar. Laureate, draped and cuirassed bust right. Rev: (…)MHTPO(…). Tyche seated left on rock, holding trophy in right hand and stele in extended left hand (?); countermark (1) behind and (2) below figure of Tyche. Ref: Spijkerman 27-36 (??). Axis: 180°. Weight: 8.35 g. Ntoe: It is not certain that this coin comes from Petra, although it seems likely. The obverse legend, however, does not seem to match any of those listed by Spijkerman. CM(1): Draped bust in circular punch, 7 mm. Howgego (?). Note: It is unlikely that this countermark corresponds to Howgego 126, since that countermark is applied to the obverse. CM(2): Δ in triangular punch, 6 x 5 mm. Howgego 801 (?) (19 pcs). Note: It is not certain that this is actually a countermark, since the outline if very faint. Although since it seems too regular to be part of the coin's design, this can not be excluded. Collection Automan.