KEY TO
THE MALE MEMBERS OF THE NORTH
AMERICAN CRAYFISH GENERA
(Except for Pacifastacus, all based on
first form Males)
NOTE: Before beginning
to use this key, it will be helpful to determine whether the first pleopods
are symmetrically or asymmetrically arranged -- see Figure
21.
1. Ischia of all pereiopods lacking hooks
(Fig. 4f: see also
Fig. 5a):
ASTACINAE:................................
......................................................................................................................................
Pacifastacus Bott, 1950
- Ischia of 1 or more pairs of pereiopods with hooks (Fig. 4a-c) .............................................................. 2
2 (1).
Ischia of second and third pairs of pereiopods with hooks (Fig.
4b; see also Fig.
5c):
CAMBARELLINAE:
...................................................................................Cambarellus
Ortmann, 1905a.
- Ischia of second pair of pereiopods never bearing hooks
(Fig. 4a, c-e):
CAMBARINAE:................
....................................................................................................................................................................... 3
3 (2). Body pigmented; eyes faceted and pigmented........................................................................................ 4
- Body albinistic; eyes seldom faceted and with pigment greatly reduced or absent ........................ 12
4 (3).
First pleopod terminating in 2 elements; long, slender central projection; short mesial process no
more that ½ length of central projection (Fig.
5w); central projections of
paired pleopods
overlapping (Fig.
19):
...........................................................................
Faxonella
Creaser, 1933 (p.29)
- First pleopod terminating in 2 or more elements; if
with 2, mesial process more than ½ length of
central projection; central projections of paired pleopods never overlapping (Fig. 5d-v) except
occasionally in Fallicambarus dissitus in which also recurved at more than 90 degree
angle (Figs. 81c, 82d): ........................................................................................................................... 5
5(4). First pleopod terminating in 2 elements (Fig. 5h-i, 1-p) ........................................................................ 6
- First pleopod terminating in more than 2 elements (Fig.
5d-g, k, q,v)..................................................
10
6(5).
Distal 1/3 of first pleopod with prominent shoulder on cephalic surface (Fig.
5h), or
central projection
forming distally projecting triangular plate (Fig.
5j), or central projection
arising from enlarged
subterminal or terminal area (Fig.
5i):................................................... Procambarus
Ortmann, 1905b (part).
- Distal 1/3 of first pleopod lacking shoulder on
cephalic surface; central projection never forming
distally projecting triangular plate nor arising from enlarged subterminal or terminal area
(Fig. 51-p, r-u): ............................................................................................................................................ 7
7(6). Coxa of fourth pereiopod lacking caudomesial boss (Fig. 6a)................................................................... 8
- Coxa of fourth pereiopod with caudomesial boss
(Fig. 6b-d)
...............................................................
9
8(7).
First pleopods, in resting position, deeply withdrawn between bases of
pereiopods and largely
concealed by
dense setiferous mat extending from ventrolateral margins of sternum (Fig.
7a):
...............................................................................................................Hobbseus Fitzpatrick
and Payne, 1968.
- First pleopods, in resting position, never deeply
withdrawn between bases of pereiopods and
never concealed by dense setiferous mat extending from ventrolateral margins of sternum
(Fig. 7b): ......................................................................................................Orconectes Cope, 1872 (part).
9(7).
Opposable margin of dactyl of chela with abrupt excision in proximal ½ (Fig.
8a):............................
.....................................................................................................................Fallicambarus
Hobbs, 1969b (part).
- Opposable margin of dactyl of chela without abrupt
excision in proximal ½ (Fig. 8b-e):...............
.......................................................................................................................Cambarus Erichson, 1846 (part).
10(5).
Central projection of first pleopod bladelike, always directed caudally or caudodistally, and
bearing subterminal notch (n) (Fig. 5q): ..............................................................................Cambarus
(part).
- Central projection of first pleopod seldom
bladelike, if so, directed laterodistally or lacking
subterminal notch (Fig. 5d-g, v): ................................................................................................................ 11
 |
| Fig. 8. Dorsal view of
right chela. a) Fallicambarus oryktes; b) Cambarus latimanus; c) C. longulus; d) C. extraneus; e) C. branchydactylus. |
11(10).
First
pleopod with central projection and mesial process curved caudally at at least
90 degrees to
principal axis of shaft of appendage (Fig.
5v):
.................................................................Fallicambarus
(part).
- First pleopod never with both central
projection and mesial process curved caudally at angle of
so much as 90 degrees to principal axis of shaft of appendage (Fig. 5d-g): .............Procambarus (part).
 |
| Fig. 9. Ventral view of left third maxillipeds. a) Troglocambarus maclanei; b) Procambarus pallidus. (i, ischium). |
12(3)
Ischium of third maxilliped (See Fig.
2) without teeth on mesial (opposable)
border (Fig. 9a;
see also Fig. 5b):.............................................................................................Troglocambarus
Hobbs, 1942a.
Monotypic:
Troglocambarus maclanei Hobbs. 1942. (Subterranean waters of
peninsular Florida.
Literature: Hobbs, 1942b)
- Ischium of third maxilliped with teeth on
mesial (opposable) border (Fig. 9b):.....................................
13
 |
| Fig. 10. Lateral view of left first pleopods. a) Cambarus hamulatus; b) C. jonesi; c) C. setosus; d) C. hubrichti; e) C. cryptodytes. |
13(12). First
pleopod terminating in 2 elements bent at no less that 90 degrees to principal
axis of shaft
of appendage
(Fig. 10):
..........................................................................................................Cambarus
(part).
- First pleopod terminating in 2 or more
elements; if only 2, both never bent at angle so great as 90
degrees to principal axis of shaft of appendage (Fig. 11): ..................................................................... 14
 |
| Fig. 11. Lateral view of first pleopods. a) Orconectes a. australis; b) P. pellucidus; c) O. i. inermis; d) Procambarus acherontis; e) P. l. lucifugus; f) P. milleri; g) P. pecki. |
14(13). First
pleopod terminating in 2 elements, sometimes with minute rudiment of third (Fig.
11a);
cephalic surface of appendage either lacking shoulder or with shoulder
adjacent to base of
central projection
(Fig. 11b,c):
............................................................................................Orconectes
(part).
- First pleopod terminating in 2
(Fig. 11g)
or more elements (Fig. 11d-f); if only 2, cephalic
surface with strong, often angular, shoulder never contiguous with base of central projection
(Fig. 11g): .........................................................................................................................Procambarus (part).
** END OF SECTION II **
TOPLast Updated:10 September 2004