Herpetology/Crocodilians and Turtles

This page contains information on members of Crocodylia and Testudines (Chelonia) on the Herpetology List. For more general information about the event, see Herpetology.

Order Crocodylia
There are 3 families of Crocodylia, with 23 species total. These families are:
 * Gavialidae (2 species: gharials and false gharials)
 * Crocodylidae (crocodiles, with 14 species in 3 genera)
 * Alligatoridae (alligators and caimans, 7 species in 4 genera)

Family Alligatoridae (alligators and caiman)
There are two extant species of alligator: Alligator mississippiensis (the American alligator) and A. sinensis (the Chinese/Yangtze alligator). There are six extant species of caiman: Caiman yacare (the Yacare caiman), C. crocodilus (the spectacled caiman), C. latirostris (the broad-snouted caiman), Melanosuchus niger (the black caiman), Paleosuchus palpebrosus (Cuvier’s dwarf caiman), and Paleosuchus trigonatus (the smooth-fronted caiman).

Family Chelydridae (snapping turtles)
Chelydridae belongs to the suborder Cryptodira and has two extant genera, Chelydra and Macrochelys. Chelydra has three species: C. serpentina (the common snapping turtle), C. acutirostris (the South American snapping turtle), and C. rossignonii (the Central American snapping turtle). Macrochelys has anywhere from one to three extant species, M. suwanniensis (the Suwannee snapping turtle, previously though to be part of M. teminckii), M. teminckii (the alligator snapping turtle), and M. apalachicolae (the Apalachicola snapping turtle, which is not generally recognized as a different species from M. teminckii).

Family Kinosternidae (musk and mud turtles)
Kinosternidae belongs to the suborder Cryptodira and is split into two subfamilies, Kinosternon (consisting of subfamilies Kinosternoninae – with Kinosternon spp., the mud turtles, and Sternotherus spp., the musk turtles – and Staurotypinae – with Claudius angustatus, the narrow-bridged musk turtle and Staurotypus spp., the Mexican/giant/three-keeled/cross-breasted musk turtles). Staurotypinae may be better as a separate family (Staurotypidae). There are 24+ species.

Musk and mud turtles are also called kinosternids (alluding to the familial name). They are close relatives to Chelydridae, the snapping turtles.

Genus Terrapene (box turtles)
Terrapene belongs to subfamily Emydinae and is comprised of 12 taxa and 4 species (T. carolina, the common box turtle, T. coahuila, the Coahuilan/aquatic box turtle, T. nelsoni, the spotted box turtle, and T. ornata, the western/ornate box turtle). Terrapene was coined by Merrem in 1820 as a genus separate from Emys for those species that had a sternum separated into two or three divisions and that could move these parts independently. The Asian box turtle belongs to a separate genus, Cuora.

Genus Actinemys (western pond turtles)
Actinemys belongs to the subfamily Emydinae and has one species, A. marmorata. The taxonomy of the western pond turtle is currently under debate; at present, the IUCN Red List recognises that the western pond turtle belongs in its own genus. However, there is deliberation that it may belong to the genus Emys which is composed of the European pond turtle (E. orbicularis), the Sicilian pond turtle (E. trinacris), and Blanding’s turtle (E. blandingii) which may belong in a separate genus itself (Emydoidea). There were previously thought to be two subspecies of the western pond turtle: the southern western pond turtle (A. m. pallida) and the northern western pond turtle (A. m. marmorata), but now there is evidence for four separate groups, which do not match the distribution of the earlier described subspecies.

Genus Malaclemys (diamondback terrapins)
Malaclemys belongs to the subfamily Deirochelyinae and has one species, M. terrapin, which has seven subspecies. The Bermuda population has not been assigned a subspecies.

Genus Graptemys (map turtles)
Graptemys belongs to the subfamily Deirochelyinae and comprises 13 species and 15 taxa.

Genus Trachemys (sliders)
Trachemys belongs to subfamily Deirochelyinae. The most famous type of slider is the red-eared slider, T. scripta elegans, a subspecies of the pond slider. Thus, the information below will be for the red-eared slider.