Crayfishes of Georgia Overview List of Georgia Species Species Lists by Drainage Crayfish Identification Keys by Drainage Ecology and Life History Links and Other Useful Information Glossary
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Dichotomous Key to the Crayfishes of the Savannah River System

This key is in need of review.

1a. Two cervical spines (Fig. 1A)..........................................go to 2
1b. One or zero cervical spines (Fig. 1B)...............................go to 3

cervical spines

Figure 1. Lateral view of crayfish indicating number and position of cervical spines. Modified from Hobbs (1981).

2a. Claw tubercles dark.................................Procambarus raneyi
2b. Claw tubercles whitish..........................Procambarus spiculifer

3a. Reddish or orangish tubercles covering dorsal surface of claw; rostrum long and pointed (Fig. 2B).....................................go to 4
3b. Reddish or orangish tubercles not found on dorsal surface of
claw; or if so, rostrum short, blunt (Fig. 2A).........................go to 5

 nodosus paeninsulanus web

Figure 2. A) Cambarus nodosus exhibiting short rostrum and B) Procambarus troglodytes with a long, pointed rostrum. Modified from Hobbs (1981).

4a.  Distocaudal margin of first pleopod of Form I male angular
(Fig. 3A).........................................................Procambarus clarkii
4b. Distocaudal margin of first pleopod of Form I male rounded
(Fig. 3B).................................................Procambarus troglodytes

 clarkii trog pleopods web

Figure 3. A) First pleopod of Form I male Procambarus clarkii indicating angular distocaudal margin; B) first pleopod of Form I male Procambarus troglodytes indicating rounded distocaudal margin. Modified from Eversole and Jones (2004).

5a. Dorsal surface of claw with orangish or reddish tubercles...........................................................Cambarus nodosus
5b. Dorsal surface of claw without orangish or reddish tubercles.............................................................................go to 6

6a. Mesial margin of palm longer than moveable finger.................................................................Faxonella clypeata
6b. Mesial margin of palm not longer than moveable finger.......go to 7

7a. Areola wide, usually less than 8 times as long as broad.....go to 8
7b. Areola narrower, 8 or more times longer than broad........go to 13

Note: Caution should be used with this character because there is some overlap with the following species: Cambarus latimanus, C. striatus, Distocambarus devexus and Procambarus barbatus.  If you are having trouble keying your crayfish, you should consider these species in the couplet opposite the one you chose.

8a. Greatest width of palm less than length of mesial margin of palm (sometimes about equal in females and individuals of Procambarus barbatus.............................................................................go to 9
8b. Greatest width of palm greater than length of mesial margin of palm...................................................................................go to 12

9a. Obvious cervical spine present.......................................go to 10
9b. No cervical spine...................................Procambarus barbatus

10a. Dorsal portion of rostrum with dense setae..........................................................Procambarus pubescens
10b. Dorsal portion of rostrum with at most, scattered
setae.....................................................................................go to 11

11a. Distal portion of male gonopod strongly bent...........................................................Procambarus epicyrtus
11b. Distal potion of male gonopod mildly bent....................................................Procambarus enoplosternum

 epicyrtus enoplosternum web

Figure 4. Left gonopods of male Procambarus epicyrtus: A) Form II, B) Form I; P. enoplosternum: C) Form II, D) Form I.  Modified from Hobbs (1981).

12a. Claws with abundant setae, appears “hairy”; tubercles on mesial margin of palm serrate.........................Cambarus asperimanus
12b. Claws without abundant setae; tubercles on mesial margin of
palm depressed or rounded.................................Cambarus bartonii

13a. Mesial margin of palm with jagged irregular tubercles.....go to 14
13b. Mesial margin of palm with similar sized tubercles...........go to 15

advena pyg depress web

Figure 3. A) Claw of A) Procambarus pygmaeus and B) P. advena indicating jagged tubercles along mesial margin of palm versus C) more typical margin of crayfish palm with smaller, similar sized tubercles.  Modified from Hobbs (1981).

14a. Color greenish with red highlights.........Procambarus pygmaeus
14b. Color brownish to pinkish brown; claws may be bluish.............................................................Procambarus caritus

15a. Length of mesial margin of palm longer than greatest width of
palm (sometimes about equal on juveniles and females).....................................................Distocambarus devexus
15b. Length of mesial margin of palm less than greatest width of palm....................................................................................go to 16

16a. More than two rows of tubercles along the mesial margin of the palm..................................................................Cambarus diogenes
16b. Two rows of tubercles along the mesial margin of the
palm..................................................................................go to 17

17a. Overall color orange-brown (one population entirely aqua-blue)..........................................................Cambarus reflexus
17b. Overall color varies.......................................................go to 18

18a. Color of tubercles on claws orangish; areola obliterated.........................................................Cambarus strigosus
18b. Color of tubercles vary; areola with at least a little space in the areola.................................................................................go to 19

19a. Areola usually more than nine times as long as broad and often obliterated (Fig. 5A); rostrum typically somewhat blunt; some populations with distinct abdominal stripes; cervical spines never present.............................................................Cambarus striatus
19b. Areola usually less than nine times as long as broad (Fig. 5B);
rostrum tapering; some individuals with indistinct abdominal stripes; cervical spines sometimes present, especially in
juveniles............................................................Cambarus latimanus

striatus latimanus dorsal web

Figure 5. Dorsal view of A) Cambarus striatus showing typically narrower areola than areola of B) Cambarus latimanus.  Modified from Hobbs (1981).

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