Dichotomous Key to the Crayfishes of the Tallapoosa River System

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

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

2a. Claws with three or more tubercles along mesial margin of the palm; spine extending beyond margin of uropod
(Fig. 2A)................................................................Cambarus acanthura
2b. Claws with two rows of tubercles along mesial margin of the palm; spine does not extend beyond margin of uropod
(Fig. 2B)...............................................................................go to 3

Figure 2. 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).

3a. Single well-developed cervical spine present.....................go to 4
3b. No cervical spine, at most cervical tubercle......................go to 6

4a. Antenna white in live individuals.......................Cambarus englishi
4b. Antenna pinkish or brownish...........................................go to 5

5a. Claws olive to greenish; rostral margins and tubercles on palm near connection of moveable finger red.........................Cambarus halli
5b. Claws brownish, no red tubercles present and no red on rostral margins................................................Cambarus latimanus, in part

Figure 3. Dorsal view of A) Cambarus striatus showing typically narrower areola than areola of B) Cambarus latimanus.  Modified from Hobbs (1981).

6a. Areola usually more than 9 times as long as broad (Fig. 3A); rostrum typically somewhat blunt; some populations with distinct abdominal stripes...................................................Cambarus striatus
6b. Areola usually less than 9 times as long as broad (Fig. 3B); rostrum tapering; some individuals with indistinct abdominal stripes.............................................................Cambarus latimanus