Ouachita Map Turtle
Graptemys ouachitensis

Size:  5 - 10 3/4 in (along carapace)
Distribution:
Eastern 1/2 of the state.  Ouachita map turtles are commonly found in lakes and streams. They have black knobs on the trailing edge of the vertebral scutes (easily seen in the above photo), and highly serrated rear marginal scutes. There are 3 species of map turtles in Oklahoma, but they can easily be distinguished by the markings on their heads. Ouachita map turtles have light yellow markings behing each eye that may be round or "L" shaped, but not encircling the eye. Additionally, they usually have two smaller round spots below each eye. Mississippi map turtles (Graptemys pseudogeographica kohnii), which can be found in much of the same range, have "L" shaped markings that mostly encircle the eye, and no round spots below the eyes.
Plain plastron of the map turtle.