FAO Species Identification Guide for Fishery Purposes Western

1074 Crabs
40a. Male first gonopod very slender, S-shaped (Fig. 73a); male second gonopod very short,
sigmoid (very short, stout, comma-shaped) less than 1/4 the length of male first
gonopod (Fig. 74b); internal and external commensals of echinoderms (Fig. 75) . . . Eumedonidae
40b. Male first gonopod moderately stout, slightly sinuous to almost straight (Fig. 73b); male
second gonopod short but not sigmoid, always longer than 1/4 the length of male first
gonopod (Fig. 74b); commensals on corals (Fig. 76) . . . . . . . . . . . . . . . . . . .Trapeziidae
a) slender,
S-shaped
b) stout,
slightly sinous
Fig. 73 male first gonopod
41a. Male abdominal segments 3
to 5 distinct, movable
(Fig. 77a); regions on carapace
usually poorly defined . . . . → 42
41b. Male abdominal segments 3
to 5 fused, immovable, although
sutures may be partially
visible (Fig. 77b, c);
regions on carapace usually
well defined . . . . . . . . . . . . . → 46
a) b)
a) sigmoid
(short, stout)
Fig. 72 Xanthidae
b) normal,
not sigmoid
Fig. 74 male second gonopod Fig. 75 Eumedonidae
6
5
5
4
3
2
1
b) segments 3-5 fused
(sutures visible laterally)
4
3
2
1
a) segments 3-5
freely movable
Fig. 77 male abdomen
6
a) b)
Fig. 76 Trapeziidae
6
5
3
4
2
1
c) segments 3-5
completely fused