The Concho Valley is home to eight species of aquatic turtles, and in my opinion none of them are as endearing as the tiny Texas Map Turtle.
Texas Map Turtles (Graptemys versa) are one of five varieties of map turtles found in Texas and one of two species found in that state and that state only. Their distribution is strictly limited to the Colorado, Concho and Llano river systems of the Hill Country and Edwards Plateau. They are also found in lakes and tributaries associated with said rivers. It is rarely, if ever, encountered on earth.
Like other members of the Northern Map Turtle family, this species can be very colorful and attractive. The carapace, or upper shell, is bright green in young animals, changing to an olive color as the animal grows. There is an intricate pattern of yellow or, more generally, orange markings on each scale of the carapace, and just like the background coloration, these lines fade as the animal ages.
The scales along the vertebral area of the carapace are elevated into a keel, and this is more prominent in juveniles than in older adults. The lower shell, or plastron, is yellowish and without a pattern, except for the dark markings on the seams that connect the scales of the plastron.
The neck and head are green, dotted with bright orange lines. Typical specimens have a large orange “J” shaped pattern that runs vertically behind each eye, and this is one of the diagnostic traits that can be used to differentiate it from other aquatic turtle species. The legs and tail are also green and are marked with orange lines similar to the neck and head.
This native turtle is one of the smallest, if not the smallest, sun-kissed aquatic turtle found within this state’s borders. Sexually mature adults have a carapace length of 3 inches to 7 inches. Females are the largest sex, reaching lengths of up to 7 inches, while males are much smaller, only reaching a carapace length of about 3½ inches. Mature males are also distinguished from females by the presence of elongated fingernails on the front legs.
Mating in this species can take place in spring or fall and begins with the male stroking the female along the length of the head with his fingernails extended in a weird but romantic courtship display.
After mating, the female will lay her small clutch of no more than six (usually two or three) eggs in mid-spring. Large, healthy females can lay up to four clutch eggs per year.
Unlike most other aquatic turtles, this species does not generally travel great distances from the water to lay its eggs. Instead, most nests are within 10 feet of the water. Once the eggs are laid in the nest, which is dug with the mother’s hind legs, they incubate for about two to three months. Once the young have hatched, they must make the short but perilous journey back to the water on their own.
The diet of this species changes as it ages, with young animals being primarily carnivorous, feeding primarily on insects and small fish, while mature individuals are herbivores, feeding on plant material.
Like most other aquatic turtles in the sun, this species is best seen as it absorbs sunlight while being exposed on tree and root snags or rocks. Despite their small size, many can be seen basking on the shells of larger species of turtles as they attempt to warm up with the sun’s rays. They are also quite suspicious and difficult to approach, which makes using binoculars the best way to observe this tiny and colorful testudine.
Michael Price is the owner of Wild About Texas, an educational company specializing in poisonous animal safety training, environmental counseling, and eco-tourism. Contact him at [email protected]
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