Description: Moderate sized turtle with an adult maximum shell length of 12.6 cm (4.9”) for males and 21.3 cm (8.3”) for females. The carapace is greenish brown and elliptical in dorsal view but rather flat in a lateral view. A slight mid-line keel is present and the second to fourth vertebral scutes are slightly elevated. The highest point of the carapace is the posterior edge of the second vertebral scute. The posterior marginal scutes are serrated. A cream colored transverse bar is present on the chin just behind the cusp and a crescent or ‘V’ shaped cream colored marking is usually present on the top of the head and between the eyes but in some specimens this is interrupted and appears as two separate blotches. The coloration of the flesh on the neck, limbs and tail is creamy yellow with dark colored stripes. The plastron and bridge are creamy yellow with brownish markings along the seams. Four longitudinal dark lines are present on the bridge. Asides from being smaller than the females, males have diminutive heads and the heads of females while noticeably larger are mesocephalic.
Distribution: Cagle’s map turtles are endemic to Texas and documented from the following rivers: Blanco, Guadalupe, Medina, San Antonio and San Marcos. Populations from the San Antonio River are considered to have been extirpated.
Habitat: Sites along the rivers with moderately high volumes of flow (0.5—0.8 m/S) with high amounts of cobble stone substrate and willow trees along the banks which can harbor high densities of leptocerid caddis fly larvae are associated with higher population densities (Killbrew, et al., 2002). Although habitats with sandy or mud covered bottoms are also occupied.
Cagle’s map turtles are negatively impacted with the presence of dams and impoundments. None are known from Canyon Lake reservoir or any of the other impoundments farther downstream, thus causing fragmentation of the populations and isolation of genetic diversity.
Conservation Status: Cagle's map turtles are a protected species listed as "Threatened" in Texas. Under the Convention of International Trade of Endangered Species it is listed as a CITES 3 species. Given the conservation status of this species it cannot be collected from the wild without specific state permits. Click here for pdf from the IUCN
CAGLE'S MAP TURTLE (Graptemys caglei), (HAYNES AND MCKOWN, 1974)
Dewitt County. Guadalupe River
Gonzales County. San Marcos River
Images from CT scan of male Graptemys caglei skull
Captive specimens. Locality data unknown