Dichotomous Key to the Crayfishes of the Coosawattee 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. Single, well developed, sharp cervical spine (Fig. 1B)..........go to 3
2b. At most single cervical tubercle, or nothing.........................go to 6

3a. Claws gaping when fingers closed (Fig. 2A), no rostral marginal spines or tubercles.............................................Cambarus speciosus
3b. Claws not gaping when fingers closed (Fig. 2B); (claw of large Cambarus coosae may be gaping somewhat but will have marginal spines or tubercles)..................................................................go to 4


Figure 2. Dorsal view of crayfish claws indicating A) gaping and B) non-gaping condition.  Modified from Hobbs (1981).

4a. Lateral edge of claw black, fingers of claw with black preapical; band...................................................Orconectes erichsonianus
4b. No black pigment present on claws...................................go to 5

5a. Overall fairly brightly colored with light orange, brown, green, and bluish hues; rostral margins reddish; cervical spine always well developed (sharp) and reddish in color; areola broad, almost appearing parallel-sided.........................................Cambarus coosae
5b. Overall drab colored, tan to brown with darker brownish mottling; rostral margins not brightly colored; cervical spine well-developed, sharp only in smaller individuals, and never red in color; areola narrower, hourglass-shaped.....................Cambarus latimanus, in part

6a. Spine extending past edge of uropod (Fig 3A)..............Cambarus acanthura
6b. Spine not extending past edge of uropod (Fig. 3B).............go to 7


Figure 3. 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).

7a. Claws gaping when fingers closed (Fig. 2A)...................Cambarus coosawattae
7b. Claws not gaping when fingers closed (Fig. 2B)..................go to 8

8a. Claw with single row of tubercles along mesial margin of palm (Fig. 4A).......................................................Cambarus conasaugaensis
8b. Claw with at least two rows of tubercles along mesial margin of palm (Fig. 4B)............................................................................go to 9


Figure 4. Dorsal view of crayfish claws indicating A) single row of tubercles along mesial margin of palm and B) more than one row of tubercles along mesial margin of palm.  Modified from Hobbs (1981).

9a. 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
9b. 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


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