Common map turtle
| Northern map turtle | |
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| Gatineau, Quebec | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Subphylum: | Vertebrata |
| Class: | Reptilia |
| Order: | Testudines |
| Family: | Emydidae |
| Subfamily: | Deirochelyinae |
| Genus: | Graptemys |
| Species: | G. geographica |
| Binomial name | |
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Graptemys geographica (Lesueur, 1817) |
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| Range map | |
| Synonyms | |
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The northern map turtle (Graptemys geographica), or common map turtle, is an aquatic turtle in the family Emydidae. It is endemic to North America. This turtle is kept as a pet.
The northern map turtle gets both its common and scientific names from the marking on the skin and carapace. The light markings resemble contour lines on a map or chart. The lines on the carapace are shades of yellow, tan, or orange and are surrounded by dark borders. The rest of the carapace is olive or greyish brown. The carapace markings on older individuals tend to fade but are usually still apparent when the shell is wet. The carapace has a hydrodynamic appearance and is broad with a moderately low keel. The rear of the carapace is flared and the rear marginals form serrations. The plastron is yellowish and is marked by a central dark blotch (plastral figure) that follows the sutures of the plastral scutes and fades with age so that many adults lack a pattern all together (i.e., the plastron is immaculate). The head, neck and limbs are dark olive, brown, or black with thin yellow or green stripes. There is an oval or triangular spot located behind the eye. Like other map turtles, this species exhibits extreme sexual size dimorphism. Males are 10–16 cm (3.9–6.3 in) in carapace length and weigh between 150–400 g (5.3–14.1 oz), while females are 18–27 cm (7.1–10.6 in) in carapace length and weigh around 0.67–2.5 kg (1.5–5.5 lb). Females have a much wider head than males and this is associated with differences in feeding. Males have a narrower carapace with more distinct keel, narrower head, and a longer, thicker tail. Unlike females, the opening of the cloaca is beyond the rear edge of the carapace. Young map turtles have a pronounced dorsal keel. Hatchlings have a round grayish-brown carapace that is about 2.5 cm (0.98 in) long.
Northern map turtles inhabit an area from south Quebec and Ontario to northern Vermont where it lives in the St. Lawrence River drainage basin. Its range extends west through the Great Lakes and into southern Wisconsin and eastern Minnesota, west of the Appalachians, south to Kansas and northwestern Georgia. It also occurs in the Susquehanna River system in Pennsylvania and Maryland and the Delaware River. Also, a small European population occurs in the Czech Republic, which was formed from escaped or released turtles and their descendants. In the Czech Republic, this turtle is considered an alien species, but is threatened together with Czech native turtles, other reptiles and amphibians by a large population of another invasive turtle, Trachemys scripta elegans.
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Wikipedia