This is some information I downloaded when I found my turtle a few years ago. I keep an eastern painted turtle I found as a hatcling in a 75 gallon tank. His name is General Lee, we love him. Hopes this helps.
The species Chrysemys picta is divided into four subspecies. While all are superficially similar, there are enough differences to make distinctions between the subspecies fairly easily accomplished. All painted turtles have a dark green to black unkeeled smooth carapace without serrations. There are often areas of red coloration at the seams between the carapace scutes.
The Eastern Painted turtle, C. p. picta, is found on the Eastern coast of North America, to the West it approaches the Eastern Great Lakes region where it intergrades with the Midland or Midwestern Painted turtle, C. picta marginata. It attains a maximum length of 16 - 17 cm although many adults are considerably smaller. The most distinguishing characteristic of the Eastern Painted turtle is that it alone of all the species of chelonia found in North America has aligned carapace scutes. Rather than being alternating as on most turtles the anterior vertebral scutes actually line up with the costals. This infraspecific feature makes this one of the most easily identified turtles in existence. C. p. picta has a plain yellow plastron and yellow stripes on the head (these may appear to be large spots on the top of the head) that change to bright red on the remainder of the body.
The Midland Painted turtle, C. p. marginata, is found from Canada through the Eastern Great Lakes to Southern Illinois. It intergrades with all three other subspecies. Of all the Chrysemys picta subspecies this is the most non-descript, having characteristics of all of the other races. The carapace scutes alternate as is typical for turtles in general. The head, neck and body markings are similar to the Eastern subspecies though the large dot like stripes on the top of the head are not present. Maximum size for this subspecies is also about 17 cm. The plastron of this subspecies has an indistinct shadowy dark marking in the center of the yellow plastron somewhat reminiscent of the dark pattern found in the Western subspecies. This marking never extends to the edge of the plastron.
The Western Painted turtle, C. p. belli, is found from Southern Canada in the North, Michigan in the East and British Columbia in the West. The range extends down the Western side of the Mississippi river to Kansas with isolated colonies being found further to the Southwest. The Western Painted reaches 20 cm in length, making it the largest of the Chrysemys. The head and body markings are yellow and the plastron is pink with a large dark design extending to the edges of the plastron. Indistinct light yellow lines can sometimes be seen on the carapace. As in all the subspecies except C. p. picta the carapace scutes alternate.
The Southern Painted turtle, C. p. dorsalis, has a distinctive red stripe down the center of its carapace. While this subspecies has the same solid yellow plastron of C. p. pictaand body coloration, it does not have the aligned carapace scutes. It is smaller than the other subspecies, reaching only 15 cm or so. The Southern Painted turtle can be found from Alabama to Southern Illinois, then South to the Gulf of Mexico. Other than isolated colonies this subspecies’ range does not extend West of the Mississippi river.
Intergrades happen between all these subspecies and it is not uncommon to find a painted turtle with morphometric characteristics present in two different subspecies.
Male and female painted turtles can easily be distinguished by the long front claws present on the males. This is both the most obvious characteristic as well as the one most easily determined by the novice. This can be readily be seen in the photo on the right of the Southern Painted turtles, Chrysemys picta dorsalis. In the photo the male is on the right. In addition to this the males have longer tails that are thicker at the base with the cloacal opening positioned further away from the body of the animal than in the female. Males also tend to be smaller than females.
