Eastern painted turtles usually have an immaculate plastron.
Midland, Eastern, or Intergrade? That is the question.

As a kid I was either skipping school to watch a warbler migration or out bugging the local (Springfield, MA) herp populations. It seemed then that either of these pursuits was a whole lot better than sitting in a classroom.

One of the herp populations that I enjoyed visiting was the huge population of painted turtles in the water lily/lotus ponds of erstwhile local park/zoo, i.e. Forest Park. I didn’t know much about herps back in those early days (I’m not sure I do now!) but I did know that there was a dramatically different suite of characteristics in those turtles. Some had plain yellow plastrons, some had plastrons smudged with dark pigment, and the plastron of others bore a well-defined central figure. I also noticed at some point in time that the carapacial scute sutures (costals and vertebrals) of those having the solid yellow plastrons went nearly straight across the carapace from side to side (excluding the marginals) while the costal sutures of the painted turtles with the plastral figures were not in line with the vertebral sutures. I don’t remember the carapacial suture configuration on the turtles with the smudged plastrons.

So, what did we have in these painted turtles? Employing the description still used today we had eastern painteds, Chrysemys picta picta (solid yellow plastron and nearly straight side to side scute sutures), midland painteds, C. p. marginata (well defined plastral figure and offset costal-vertebral sutures) and intergrades (smudged plastrons).

And therein lies the problem, a problem unbeknownst to me then, and of no interest to the turtles either then or now. But while the easterns and even the intergrades could be easily explained, the presence of 2 well defined subspecies, the eastern and the midland, in the same puddles should not have occurred. Could our descriptive criteria be faulty? Awww heck. As long as the turtles don’t care why should it bother us.