FAO Species Identification Guide for Fishery Purposes Western

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1056 Crabs
Guide toGUIDE FamiliesTO
FAMILIES OF INTEREST TO FISHERIES OCCURRING IN THE AREA
HOMOLIDAE Page 1083
Deep-water carrier crabs
Carapace longitudinally rectangular; dorsal surface
granulose to spinose; front narrow, usually with 3
long horn-like projections (rostra). Male chelipeds
long. Last pair of legs inserted obliquely on carapace
and directed upwards, reduced, subchelate to
chelate, modified to carry sponges. All male abdominal
segments distinct, movable.
DROMIIDAE Page 1085
Sponge crabs
Carapace circular to hexagonal; dorsal surface gently
to strongly convex longitudinally and transversely,
smooth or granular, usually setose; front narrow,
usually entire; anterolateral margins of carapace
strongly convex, unarmed, or with small spines. Last
2 pairs of legs inserted obliquely
on carapace and directed upwards,
strongly reduced, subchelate,
modified to carry
sponges or tunicates on back of
carapace. All male abdominal
segments distinct, movable; a
small platelet-like structure usually
intercalated between edges
of sixth abdominal segment and
telson. Male first gonopod stout,
simple; male second gonopod
long, usually subequal or longer
than length of male first gonopod.
Male and female genital openings
sternal.
male
abdomen
RANINIDAE Page 1089
Spanner crabs
Carapace longitudinally ovate; dorsal surface
strongly granulose or squamose to smooth;
front triangular, narrow. Third maxillipeds very
narrow, merus distinctly triangular. Eyestalks
long, longer than front. Fingers of chela
strongly bent; at least 1 pair of legs with last 2
or 3 segments paddle-like. Thoracic sternum
very narrow, especially sternites 5 to 7. All
male abdominal segments distinct, movable.
6
5
4
3
plate-like
structure
triangular
merus
right 3 rd
maxilliped
last 2 pairs of legs
subchelate
narrow front
(or rostrum)
carapace
longitudinally
rectangular
last legs
reduced,
subchelate
to chelate
carapace
circular to
hexagonal
fingers
strongly
bent
carapace
longitudinally
ovate
at least 1 pair of legs paddle-like