Graptemys geographica

Lamb et al. (1994) conducted a mtDNA-based phylogenetic analysis of turtles in the genus Graptemys and discovered three monophyletic lineages: G. pulchra group (including G. pulchra, G. gibbonsi, G. ernsti, and G. barbouri); G. pseudogeographica group (including G. pseudogeographica, G. nigrinoda, G. flavimaculata, G. oculifera, G. versa, G. caglei, and G. ouachitensis); and G. geographica. Overall genetic divergence was relatively low, and G. pseudogeographica, G. nigrinoda, G. flavimaculata, G. oculifera, and G. versa all shared the same mtDNA genotype. There was no evidence of infraspecific variation in any species. Walker and Avise (1998) reviewed these data and suggested that the Graptemys complex has been taxonomically oversplit at the species level.

McDowell (1964) concluded that the genus Graptemys should be included in the genus Malaclemys, but this arrangement generally has been rejected (e.g., see Dobie 1981 for information on osteological differences between the two genera).

Crother et al. (2008) has changed the name from Common Map Turtle because of the possibility that the word "common" might be misinterpreted to imply abundance rather than to the fact that it has a broad geographic distribution.

See Freedberg and Myers (2012) and Mitchell et al. (2016) confirming hybridization between G. geographica and G. pseudogeographica.

A widespread and often abundant species, but like other turtles, faces numerous threats; believed to be declining in some regions.

Range is primarily in inland eastern United States and parts of southeastern Canada. Ranges from southwestern Quebec, southern Ontario, and northwestern Vermont to central Minnesota, south in Mississippi River drainage to Arkansas, northern Alabama (to Tombigbee drainage above Fall Line), and eastern Tennessee, west to eastern Kansas; Ohio River drainage from West Virginia to Illinois. Isolated populations in Delaware and Susquehanna river drainages of Pennsylvania, Maryland, and New Jersey; and in Hudson River, New York (McCoy and Vogt 1990, Daigle et al. 1994, Ernst and Lovich 2009, COSEWIC 2012, Environment and Climate Change Canada 2019).

A widespread, often abundant species (Ernst and Lovich 2009)..

Numerous threats, detailed by Ernst et al. (1994), Ernst and Lovich (2009), COSEWIC (2012), Vogt et al. (2018), and Environment and Climate Change Canada (2019):
Loss and degradation of habitat is a key threat, both directly through waterfront development and hydro infrastructure; and indirectly through pollution and sedimentation that impacts or eliminates the turtle's molluscan food, and through woody debris removal (Bodie 2001, Smith et al. 2006, Vogt et al. 2018). Females traveling to nesting areas are subjected to the threat of road traffic (Andrews et al. 2006, Steen et al. 2006). Because this species inhabits large lakes and rivers, collisions with power boats can be a serious threat (Vogt et al. 2018). Turtles are also killed by direct exploitation for consumption and the pet trade, and through bycatch in commercial riverine fisheries (Midwood et al. 2015, Vogt et al. 2018). Dams and locks apparently impede movement of females (Bennett et al. 2010, Richards-Dimitrie 2011) and can affect the growth rate of individuals and the sex ratio in the population (Bennett et al. 2009).