The yellow-blotched map turtle is a member of the narrow-head complex of Graptemys. It is a medium-sized aquatic turtle with females attaining a carapace (upper shell) length of a least 2O centimeters (cm) (8 inches) and males occasionally exceeding 12 cm (4 and 3/4 inches). The carapace is olive to light brown. Each costal scute has an irregular bright yellow or orange blotch. Juveniles and adult males have a black spine on the first four vertebral scutes. These spines become smaller and may be lost in adult females.