Dichotomous Key to the Crayfishes of the Chattahoochee River System

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

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

2a. Cream or brown stripe on side of carapace; claw tubercles dark............................................................Procambarus versutus
2b. No cream stripe; claw tubercles whitish....Procambarus spiculifer

3a. Rostrum long and pointed; claw tubercles reddish or orangish
(Fig. 2A).............................................................................go to 4
3b. Rostrum short and blunt; may or may not be reddish or orangish (Fig. 2B).....................................................................go to 5

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

4a. Areola usually obliterated.........................Procambarus clarkii
4b. Areola with at least some space.....Procambarus paeninsulanus

5a. Mesial margin of palm longer than moveable
finger.....................................................................Faxonella clypeata
5b. Mesial margin of palm not longer than moveable finger......go to 6

6a. Length of mesial margin of the palm greater than width of palm (sometimes about equal on females)............................................to 7
6b. Length of mesial margin of palm less than width of palm...go to 8

7a. Male gonopod as in Fig. 3A-C and female annulus ventralis as in Fig. 3D........................................................Procambarus acutissimus
7b. Male gonopod as in Fig 3E-G and female annulus ventralis as in Fig. 3H.........................................................Procambarus verrucosus

Figure 3. Procambarus acutissimus A) lateral view of left gonopod; B) lateral view of left gonopod with setae removed; C) mesial view of left gonopod with setae removed; D) female annulus ventralis. Procambarus verrucosus, E) lateral view of left gonopod; F) lateral view of left gonopod with setae removed; G) mesial view of left gonopod with setae removed; H) female annulus ventralis. Modified from Hobbs (1989).

8a. Spine extending past end of uropod
(Fig. 4A)............................................................Cambarus acanthura
8b. Spine not extending past end of uropod (Fig. 4B)............go to 9

Figure 4. Position of spine on mesial ramus of uropod.  A) Spine extending past edge of uropod; B) spine not extending past edge of uropod.  Modified from Hobbs (1981).

9a. Single row of tubercles along mesial margin of the
palm...................................................................................go to 10
9b. More than one row of tubercles along mesial margin of the palm.....................................................................................go to 11

10a. Color brown with darker mottling...Cambarus bartonii bartonii
10b. Color greenish to olive with red highlights.....Cambarus howardi

11a. Two rows of tubercles along mesial margin of the palm...go to 12
11b. More than two rows of tubercles along mesial margin of the palm.................................................................Cambarus diogenes

12a. Areola obliterated........................................................go to 13
12b. Areola with at least some space...................................go to 14

13a. Color blue, most intense on claws....................Cambarus harti
13b. Color tan to greenish with a pale stripe on
abdomen.......................................................Fallicambarus fodiens

14a. Claws with whitish to orangish tubercles......Cambarus nodosus
14b. Claws without whitish or orangish tubercles..................go to 15

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

15a. Areola usually more than 9 times as long as broad (Fig. 5A); rostrum typically somewhat blunt; some populations with distinct abdominal stripes; cervical spines never present....Cambarus striatus
15b. Areola usually less than 9 times as long as broad (Fig. 5B);
rostrum tapering; some individuals with indistinct abdominal stripes; cervical spines sometimes present, especially in
juveniles............................................................Cambarus latimanus