Key to Freshwater Turtles in BC

BC Freshwater Turtle Key

Fist draft prepared by: Gavin Hanke, RBCM (Sep 2011)

Modified from: Powell et al. 1998

See glossary for explanation of terms.


1a) carapace leathery without horny scutes and flexible at edges; 3 claws on forelimb; nose elongate and tubular - go to 2
1b) carapace firm with horny scutes; nose not tubular; more than three claws on forelimb - go to 4

 

2a) nasal septum with lateral ridges projecting into nostril (see picture); anterior end of carapace with tubercles - go to 3

           Spiny Softshell Turtle
2b) no lateral ridges off nasal septum; anterior margin of shell not tuberculate - Smooth Softshell Turtle (Apalone mutica)

 

3a) tubercles on carapace in more than one row; carapace with ridge on marginFlorida Softshell Turtle (Apalone ferox)
3b) tubercles in single row along anterior margin of carapace; carapace lacks marginal ridge - Spiny Softshell Turtle (Apalone spinifera)

 

4a) in adults, tail longer than 1/3rd plastron length; tail with prominent knobby scales along the dorsal midline; carapace heavy and may have a single raised knob per scale or can be smooth; plastron reduced to cruciform shape; evenly brown to black colouration with some dark mottling in pale specimens; legs powerful with large heavy claws - Common Snapping Turtle (Chelydra serpentina)
4b
) in adults, tail 1/3rd plastron length or shorter - go to 5

 

5a) carapace smooth or with concentric ridges per scale; carapace brown to black, but may have fine light radiating dashes in light coloured specimens; limbs with very fine light yellow flecks or yellow brown mottling; plastron uniformly coloured, and ranges from yellow to brown to black, some have dark plastron with a light margin; axillary and inguinal scutes absent or rudimentary - Pacific Pond Turtle (Clemmys marmorata)
5b) axillary and inguinal scutes well-developed - go to 6


6a) carapace with single median or up to three longitudinal ridges - go to 7
6b) carapace forms a smooth dome without prominent longitudinal ridges - go to 8


7a) carapace brown to black; carapace with three longitudinal ridges; may have well-separated yellow spots and stripes on head; legs mostly dark; plastron uniformly dark or may have a large dark triangle or polygonal patch per scale - Reeve's Turtle (Chinemys reevesi)
7b) carapace with a mid-dorsal series of raised knobs only on vertebral scutes; carapace olive green and may have fine vermiculations; rear margin of carapace serrated; plastron with dark colouration where scutes meet and pale towards scute centres; head with fine white and yellow stripes; crescentic stripe behind eye; iris with bright grey green colouration - Mississippi Map Turtle (Graptemys kohni)


8a) plastron with single hinge just behind forelimb (hinge between abdominal and pectoral scales allows the turtle to protect itself from predators by closing the gab between the plastron and the carapace)- go to 9
8b) plastron with no hinge - go to 10

 

9a) hinge level with 6th marginal scute or level with junction between 5th and 6th marginal scutes; no trace of mid-dorsal keel on carapace; junction between femoral scutes more than ½ as long as that between abdominal scutes - Ornate Box Turtle (Terrapene ornata)
9b) hinge level with rear half of 5th marginal scute; mid-dorsal keel weakly expressed on carapace; junction between femoral scutes less than ½ as long as that between abdominal scutes - Eastern Box Turtle (Terrapene carolina)


10a) first marginal scute usually not extending lateral to suture between 1st vertebral and 1st coastal scutes; posterior margin of carapace not serrated; scutes on carapace smooth - go to 11
10b) first marginal scute extends lateral to suture between 1st vertebral and 1st costal scute; posterior margin of carapace serrated; scutes on carapace can have concentric ridges or furrows - go to 14.

 

11a) plastron red to orange with large central irregularly patterned blotch - go to 12
11b) plastron yellow-orange with no dark patches - go to 13

 

12a) dark blotch on plastron expanded into a fanciful oak-leaf pattern with complex vermiculations - Western Painted Turtle (Chrysemys picta bellii)
12b) dark blotch on plastron restricted to the midline, commonly restricted to the posterior third of the plastron and may be interrupted - Midland Painted Turtle (Chrysemys picta marginata)

 

13a) carapace with mid-dorsal red to orange pin-stripe - Southern Painted Turtle (Chrysemys picta dorsalis)
13b) carapace lacking mid-dorsal red to orange pin-stripe - Eastern Painted Turtle (Chrysemys picta picta)

 

14a) underside of jaw ('chin') rounded; postorbital spot or stripe at least ½ the eye diameter; usually with prominent orange-red or yellow spot or stripe behind eye - go to 15
14b) underside of jaw ('chin') straight; postorbital spot or stripe less than ½ the eye diameter - go to 16

 

15a) plastron yellow with several separate black blotches; carapace smooth or with concentric ridges and furrows per scale; carapace light green to black with dark dashes or bars in older individuals; orange to brown "ear" marking - Red-eared Slider (Trachemys scripta elegans)
15b) plastron yellow with none or few black blotches; carapace usually with concentric ridges and furrows per scale; carapace light green to black with dark dashes or bars in older individuals; head with bold yellow lazy-Z-stripe - Yellowbelly Slider (Trachemys scripta scripta)
15c) plastrone orange/yellow; head with an orange postorbital stripe - Cumberland slider (Trachemys scripta troostii)

 

16a) upper jaw lacking prominent cusps; plastron may have dark markings; second costal scute with pale to indistinct C-shaped mark - River Cooter (Pseudemys concinna)
16b) upper jaw with prominent cusps; second costal scute with light blotches or vertical bar; plastron orange-red with irregular dark blotches and spots; dark spots or oblong spots on bridge and underside of marginals have light centres; para-median lines extending between eyes; 5 lines in total between eyes - Redbelly Cooter (Pseudemys rubriventris)