Reptiles Guide

Testudines are an order of reptile commonly known as turtles, tortoises and terrapins. The testudines are some of the most ancient reptiles alive, with only the tuataras considered more primitive. There are approximately 300 extant species of testudines, split into two suborders: the Cryptodirans and the Pleurodirans. The distinction between these two suborders is based on the mode in which they cover their head and neck. The Pleurodirans, also called the side-necked turtles, have long necks, and fold them sideways to align them with the shell. The Cryptodirans pull their neck straight back to conceal their head within the shell.

Cryptodira - 11 families, 74 genera, over 200 species
Family	Genera	Common Names	Example Species	Example Photo
Carettochelyidae Boulenger, 1887	1	Australiasian Pig-nose Turtle	Australasian Pig-Nose Turtle (Carettochelys insculpta)
Cheloniidae Oppel, 1811	5	Sea turtles	Green Sea Turtle (Chelonia mydas)
Chelydridae Gray, 1831	2	Snapping turtles	Alligator Snapping Turtle (Macrochelys temminckii)
Dermatemydidae Gray, 1870	1	Mesoamerican River Turtle	Mesoamerican River Turtle (Dermatemys mawii)	-
Dermochelyidae Fitzinger, 184	1	Leatherback Sea Turtle	Leatherback Sea Turtle (Dermochelys coriacea)
Emydidae Rafinesque, 1815	10	Box or water turtles	Red-eared Slider (Trachemys scripta elegans)
Geoemydidae Theobald, 1868	24	Asian river, leaf, roofed or Asian box turtles	Eastern Box Turtle (Terrapene carolina carolina)
Kinosternidae Agassiz, 1857	4	Mud or musk turtles	Common Musk Turtle (Sternotherus odoratus)
Platysternidae Gray, 1869	1	Big-headed turtles	Big-headed Turtle (Platysternon megacephalum)	-
Testudinidae Batsch, 1788	11	Tortoises	Aldabra Giant Tortoise (Geochelone gigantea)
Trionychidae Fitzinger, 1826	14	Softshell turtles	Spiny Softshell Turtle (Apalone spinifera)

Pleurodira - 3 families, 16 genera, over 60 species
Family	Genera	Common Names	Example Species	Example Photo
Chelidae Gray, 1831	11	Austro-American Sideneck Turtles	Common Snakeneck Turtle (Chelodina longicollis)
Pelomedusidae Cope, 1868	2	Afro-American Sideneck Turtles	African helmeted turtle (Pelomedusa subrufa)	-
Podocnemididae Gray, 1869	3	Madagascan big-headed and American sideneck river turtles	Madagascan Big-headed Turtle (Erymnochelys madagascariensis)

References

• John B. Iverson, A. Jon Kimerling, A. Ross Kiester. EMYSystems. Terra Cognita Laboratory, Geosciences Department of Oregon State University. Retrieved on 2006-06-15.
• David T. Kirkpatrick (November/December 1995). Platysternon megacephalum pp. 40 - 47.. Reptile & Amphibian Magazine. Retrieved on 2006-07-27.
• Cogger, H.G., R.G. Zweifel, and D. Kirschner (2004). Encyclopedia of Reptiles & Amphibians Second Edition. Fog City Press. ISBN 1-877019-69-0.