General Description: The False Map Turtle is a large riverine turtle with carapace lengths ranging from 9–10 inches (22.9–25.4 cm) in females and 4–6 inches (10.2–15.2 cm) in males. Females are approximately 1.5 times larger than males, and males have longer, thicker tails and longer claws on their forelimbs than females. The carapace is brown to olive in coloration, often with a dark mark on each scute, with a medial keel along the midline and posterior marginal scutes that are serrated. The carapace also has pale yellow lines that form a reticulated pattern on the shell, though this is more prominent in juveniles than adults. Similarly, the neck, head, and limbs are covered in yellow lines, with distinct “L” mark just behind each eye. The plastron lacks a hinge and is a pale cream in coloration with dark blotches that often fade over time. The hind feet are webbed and to form a paddle to assist it while swimming through swift currents. It can easily be distinguished from other South Dakota turtles by the presence of a keel along the midline of the carapace and serrated posterior marginal scutes.
Behavior: False Map Turtles are omnivorous, often feeding primarily on invertebrates, but also fish, carrion, and plant material. These turtles spend many hours on sunny days basking on rocks and logs and are primarily active during the day. The False Map Turtle is a strong swimmer, as it inhabits rivers with moderate to swift currents. Individuals overwinter in mud and organic material at the bottom aquatic habitats.
Reproduction: Most breeding activity takes place in early spring and females lay eggs from May to June. Clutch sizes range from 12–16 eggs and are laid in bare sandy substrates, including in sandbars in the river channel.
Habitat: False Map Turtles are primarily a riverine species, being commonly found in large rivers. Additionally, they can be found in slower backwaters and oxbow lakes that occur in river floodplains. Juveniles are typically found in slower-moving water than adults.
Species Range: This species occurs in the Mississippi and Missouri Rivers and large tributaries that feed them from North Dakota and Minnesota south throughout much of Missouri, Arkansas, Louisiana, and east Texas.
South Dakota Range: This species only occurs in the Missouri River and associated large tributaries.
South Dakota Status: The False Map Turtle is a state threatened species. Additionally, it is listed on the South Dakota Natural Heritage Program. Any sightings of this species should be reported to South Dakota Game, Fish and Parks (report observation).
Account written by Drew R. Davis and Amanda M. Hegg