Testudines (Tortoises, Turtles and Terrapins)


Testudines is an order of reptilian tetrapods commonly called turtles (including tortoises and terrapins). All fossil and living members of the group have a shell that encloses both of the limb girdles. The group has its origins in the Triassic and is now represented by 13 living families, many of which contain species in danger of extinction.

Keywords: turtles; tortoises; terrapins; chelonians; Testudinata

Figure 1.

The turtle shell. Top row, dermal bones, and bottom row, epidermal scales, of the turtle shell. The carapace is shown in dorsal view (left side) and the plastron is shown in ventral view (right side). Mesoplastra, supramarginals and a complete set of inframarginals are absent in most living turtles. Modified from Zangerl R (1969) The turtle shell. In: Gans C, Bellairs A and Parsons TS (eds) Biology of the Reptilia, vol. 1, pp. 311–339. San Diego, CA: Academic Press.

Figure 2.

The phylogeny of turtles. All living and the better known fossil families are included. The arrangement of the tree follows Gaffney and Meylan , Gaffney and Shaffer et al. . See Further Reading for citations.


Further Reading

Ernst CH and Barbour RW (1989) Turtles of the World. Washington, DC. Smithsonian Institution Press.

Ernst CH, Barbour RW and Lovich JE (1994) Turtles of the United States and Canada. Washington, DC: Smithsonian Institution Press.

Gaffney ES (1990) The comparative osteology of the Triassic turtle Proganochelys. Bulletin of the American Museum of Natural History 194: 1–263.

Gaffney ES (1996) The postcranial morphology of Meiolania platyceps and a review of the Meiolaniidae. Bulletin of the American Museum of Natural History 229: 1–166.

Gaffney ES and Meylan PA (1988) A phylogeny of turtles. In: Benton MJ (ed.) The Phylogeny and Classification of Tetrapods, vol. 1. Amphibians, Reptiles, Birds, pp. 157–219. Oxford: Clarendon Press.

Gibbons JW (1990) Life History and Ecology of the Slider Turtle. Washington, DC: Smithsonian Institution Press.

Harless MD and Morelock H (1979) Turtles: Perspective and Research. New York: John Wiley.

Iverson JB (1992) A Revised Checklist with Distribution Maps of the Turtles of the World. Richmond, IN: Privately Printed.

Pritchard PCH (1979) Encyclopedia of Turtles. Neptune, NJ: TFH Publications.

Shaffer HB, Meylan PA and McKnight ML (1997) Test of turtle phylogeny: molecular, morphological, and paleontological approaches. Systematic Biology 46: 235–268.

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How to Cite close
Meylan, Peter A(May 2001) Testudines (Tortoises, Turtles and Terrapins). In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0001541]