The Mississippi Map Turtle (Graptemys pseudogeographic kohni) originates in the Mississippi River basin, but it has lately emerged as a common species in the pet trade. As a result it has begun to show up in wetlands in the Lower Mainland and on the east coast of Vancouver Island.
Identification of the species is aided by the prominent keel with "spikes" along the center of the carapace. Adult map turtles are relative small compared to the more common sliders.
There are two recognized subspecies the Mississippi Map Turtle, and the False Map Turtle (G. p. pseudogeographica) is similar. The Mississippi Map Turtle can be distinguished by its white beak and white live behind the eye that lacks a transverse bar. The False Map has a yellow beak and a white marking behind the eye with a transverse bar.
The map-like markings on the carapace gives its common name.
More information can be found at the Mississippi Map Turtle page on Wikipedia