Pseudemys peninsularis, the Peninsula cooter; Volusia county, Florida; 15 March 2015. http://phostracks.com.
Downstream of Dolan Falls, there is a deep pool. We spotted couple of cooters swimming at shallow depth, enough to see their shape. Unfortunately, we weren't able to see more detail but I think the Rio Grande cooters are the only ones that occur in the region.
Pseudemys is a genus of large, herbivorous, freshwater turtles of the eastern United States. They are often referred to as cooters, which stems from kuta, the word for turtle in the Bambara and Malinké languages, brought to America by African slaves.