Graptemys pseudogeographica in the Upper Missouri River of the Northcentral United States
Timken RL. 1968. Graptemys pseudogeographica in the Upper Missouri River of the Northcentral United States. Journal of Herpetology. 1(1-4):76-82
The known range of Graptemys pseudogeographica (Gray) is extended some 250 miles up the Missouri River and a specimen representing the first state record for North Dakota is reported. The use of wire funnel traps proved an effective method for collecting G. pseudogeographica. G. pseudogeographica is really much more abundant in the upper Missouri River than had been reported, and this species is probably much more abundant in the northcentral United States than has been believed. A new record for maximum size is reported for the species. Population data concerning sex ratios and size classes of turtles larger than 8.0 cm plastral length are discussed. A larger total number of females existed in the population studied, but the ratio of sexually mature females to sexually mature males was about equal. The largest group of individuals in the population was composed of immature females. It was determined that males probably became sexually mature at some plastral length below 10 cm; female sexual maturity occurs at a plastral length of 18 cm to 19 cm. Coloration and marking patterns of these turtles are discussed.
- Type
- Journal Article
- Authors
- Timken, Richard
- Units
- MNRR
- Keywords
- Animal Studies, Ecology, Inventory and Monitoring (I&M), Reptilia (Reptiles)