Stejneger, 1925b
Texas map turtle
Recognition
The elliptical carapace (to 21.4 cm) is somewhat flattened, wider posteriorly, and has strongly serrated posterior marginals. The medial keel contains low knobs which are often dark tipped with a yellow area anterior to each. Carapacial scutes are distinctly convex. The carapace is olive, with reticulating yellow lines on each scute. Marginals are patterned dorsally with reticulating yellow lines, and ventrally with fine dark lines surrounding irregular yellow blotches. The plastron is well-developed and contains a posterior notch. Its scute formula is: abd > an > fem > pect >< hum >< gul. The plastron is yellow and has a pattern of dark lines along the seams; fine, dark, longitudinal bars cross the bridge. The head is narrow in both sexes, and the snout is somewhat pointed. Triturating surfaces of the jaws are not greatly enlarged. The head is olive with a horizontal or J-shaped, orange or yellow postorbital mark on each side. These marks extend backward at their lower (outer) edge, and may be interrupted. Three to six fine yellow stripes extend up the neck from the tympanum and enter the orbit. The chin often has a pattern of orange or yellow, dark-bordered blotches. Other skin is olive, with many dark lines surrounding yellow areas.
The karyotype is composed of 50 chromosomes: 11 pairs of metacentric or submetacentric and 2 pairs of acrocentric macrochromosomes, and 12 pairs of microchromosomes (McKown, 1972).
Adult males are 6.5-11.2 cm in carapace length, adult females 9-18.3 cm. Males have long, thick tails, with the vent posterior to the carapace margin.
Distribution
Graptemys versa is found in the Colorado River watershed on the Edwards Plateau of central Texas.
Habitat
Graptemys versa occupies shallow streams with moderate current.
Natural History
Male courtship apparently involves head bobbing (Ernst and Barbour, 1972). The record length female had an enlarged head, possibly an adaptation to a molluscivorous diet, as it passed snail shells in its feces (Kizirian et al., 1990). Captives have eaten fresh and canned fish, chicken, beef, hamburger, dog food, insects, and occasionally lettuce.
IUCN Red List Status (1996)
Lower risk: near threatened.