I favor genus Pterostichus - subgenus Abacidus characterized by broad based pronotum having pair of prominent grooves near each hind angle. Image appears most like Pterostichus (Abacidus) permundus present in OK and in my state WI. The striking elytral iridescence normally seen in that species is missing from the image because of camera angle most likely. I noticed that there are really no other species in Oklahoma that fall into Abacidus.

Image also bears some resemblance to the pterostichine genus Myas. However, I dismissed Myas in part because it is not listed on the Oklahoma checklist.