Help w/ AE 23 Empress coin - Horseback reverse

[newone]

AE 23 ObV: IOV (S?)AIA(dot)AVP - Empress rt.
Rev: NIKO(?)IA - Emperor on horseback rt., cape waving holding spear. (Looks like PAM under front feet of hores?)
I've checked Julia Mamaea and Julia Maesa and other empresses without success. Any ideas on it? Thank you.

[newone]

OOPS - Here's the obverse.

[Steve Minnoch]

Julia Mamaea

IOYΛIA MA-MAIA AVΓ

If your reading of the start of the rev is correct, it is presumably Nicomedia... NIKOMHΔΕΩN ΔΙC ΝΕΩΚ or similar

Steve

[newone]

HI Steve - You're right on w/ the reverse being Nicomedia. I curious about the letters under the horse's front feet. Looks like PAM. Offhand do you happen to have a number on this one?

[curtislclay]

Probably the last three letters of the rev. legend,

NIKOMHΔΕΩN ΔΙC ΝΕΩΚO - PΩN.

[newone]

Thank you Curtis - always a pleasure hearing from you. After looking a bit closer that appears to be what it is. This seems to be a tough one to find online, I'm running out of ideas where to look. Once again - Thanks!

[archivum]

Perhaps this one (from Isegrim), though if your coin weighs quite a bit less they may represent different issues:

PRO: BITHYNIA
PO : NICOMEDIA
PZ : Between 222 and 235 
TIG: NEWKORWN DIS
 Obverse
VSG: IOYLIA MAMAIA AYG
VT : PORTRAIT WOMAN R / MAMAEA
VA : CLOTHES
 Reverse
RSG: NIKOMHDEWN DIS NEWKORWN
RT : MAN RIDING R(1) / EMPEROR(1)
RA : SPEAR(1)
 Technical details
M  : AE
GEW: 9.46(1)
 Bibliographical references
ZIT: SNG AUL 786(1)
 Additional remarks
FR : VS: IOYLIA MAMAIA AYG RS: NIKOMHDEWN D<IS> NEWKORWN 

[curtislclay]

Your coin would appear to be from the same dies as SNG Aulock 786, which Archivum located in Isegrim.

[newone]

Thanks to all for the info - never would've gotten it on my own!