Graptemys

Graptemys
Graptemys pseudogeographica,
false map turtle
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Superfamily: Testudinoidea
Family: Emydidae
Subfamily: Deirochelyinae
Genus: Graptemys
Agassiz, 1857[1]
Species

14, see text

Synonyms[2]

Graptemys Agassiz, 1857[1]
Malacoclemmys Cope, 1875 (in part)[3]
Malaclemys McDowell, 1964[4]

Graptemys is a genus of freshwater turtles containing 14 species, commonly known as map turtles.[5] Graptemys are small to medium-sized turtles that are significantly sexually dimorphic, with females in some species attaining as much as twice the length and ten times the mass as males. Depending on the species, adult males range from 7–16 cm (2.75–6.25 in), adult females 10–29.5 cm (4–11.62 in), and hatchlings 2.5–3.8 cm (1–1.5 in),[6]: 202–209 p.  although some sources indicate female Barbour's map turtles (Graptemys barbouri) grow to 33 cm (13 in) in length.[7] Most species have a distinctive dark pigmented keel that is often notched or serrated running down the center of the carapace and serrated scutes on the rear margin. The head, neck, and limbs exhibit bold patterns of yellow (occasionally orange or red) lines and spots against darker green, olive, or black base colors. The patterns on the head can be important characters in identifying the various species. The common name "map turtle" is derived from the intricate patterns on their shells that are suggestive of topographical maps, although the patterns are more apparent in some species than others, and often become obscure in older specimens. Some species are occasionally called "sawbacks", in reference to the serrated keels on their shell.[8][9]

They are endemic to North America, where most species occur in the rivers of the Gulf Coast of the United States, although three species are more wide-ranging, dispersed throughout the eastern two thirds of the greater Mississippi River basin, into the Great Lakes region, and east to New York and southeast Canada. Most Graptemys are lotic (river) turtles, having a preference for moving water and larger lakes, and with long legs, broad feet, and long fully webbed digits they are well adapted for swimming in currents. They primarily feed on fresh water mussels, clams, snails, insects (including larva and eggs), bryozoans, sponges, algae, and various vegetation. Fish only appear in the diets of a few species and then only in a relatively small percentage of the diet. Within this spectrum of food items there is significant niche partitioning among the sexually dimorphic males and females, and microcephalic, mesocephalic, and megacephalic species occurring in the same river drainages. Like all turtles, map turtles are oviparous, typically laying eggs from late June to August. Females lay two to 15 eggs per clutch and depending on a number of variables such as species, size, and age among other factors, may skip a year between clutches, or lay as many four clutches a year.[8][9]

Seven of the 14 species are listed as either near threatened, vulnerable, or endangered by the IUCN Red List as of 2021,[10] and two species, the yellow-blotched map turtle (G. flavimaculata) and the ringed map turtle (G. oculifera) are listed as threatened by the U.S. Federal Government.[11]

  1. ^ a b Agassiz, Louis (1857). Contributions to the Natural History of the United States, Vol. I. Little, Brown and Co., Boston.
  2. ^ McCoy, C. J., and Richard C. Vogt (1994). Graptemys. Catalogue of American Amphibians and Reptiles. Society for the Study of Amphibians and Reptiles. 584.1-584.3.
  3. ^ Cope, Edward D. (1875). "Check-list of North American Batrachia and Reptiles with a Systematic List of the Higher Groups". Bulletin of the United States National Museum (1): 1-104. [page 53]
  4. ^ McDowell, Samuel B. (1964). "Partition of the genus Clemmys and related problems in the taxonomy of the aquatic Testudinidae". Proceedings of the Zoological Society of London 143: 239-279.
  5. ^ Crother, B. I. (editor) (2017). Scientific and Standard English Names of Amphibians and Reptiles of North America North of Mexico, with Comments Regarding Confidence in Our Understanding. SSAR Herpetological Circular 43, 1–102 pp. [see page 86] ISBN 978-1-946681-00-3
  6. ^ Powell, Robert, Roger Conant, and Joseph T. Collins (2016). Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America. Boston and New York: Houghton Mifflin Harcourt. xiii + 494 pp. [pages 202-209] ISBN 978-0-544-12997-9
  7. ^ Sanderson, Roger A., and Jeffrey E. Lovich (1988). Graptemys barbouri. Catalogue of American Amphibians and Reptiles. Society for the Study of Amphibians and Reptiles 421: 1-2.
  8. ^ a b Lindeman, Peter V. (2013). The Map Turtle and Sawback Atlas, Ecology, Evolution, Distribution, and Conservation. (Vol. 12 Animal Natural History Series). Norman, Oklahoma: University of Oklahoma Press. xxi + 460 pp. ISBN 978-0-8061-4406-1
  9. ^ a b Ernst, C. H., and J. E. Lovich (2009). Turtles of the United States and Canada. Baltimore, Maryland: Johns Hopkins University Press. xii + 827 pp. ISBN 0-8018-9121-3
  10. ^ IUCN Red List: Search, Graptemys (accessed 29 October 2021)
  11. ^ U.S. Fish & Wildlife Service, Species by Taxonomic Group - Reptiles (accessed 29 October 2021)