| 1a |
Body as a whole almost ovoid; leg 1 not chelate
or subchelate;
telson
twice as long as wide; found only on exposed sandy beaches, burrowing
just
under the surface |
Superfamily Hippoidea: Family Hippidae,
Emerita
analoga |
| 1b |
Body as a whole not ovoid; leg 1 chelate
or subchelate;
telson,
if obvious, not twice as long as wide; generally in rocky or stony
situations,
on muddy bottoms, or living in permanent burrows in mud or muddy sand |
2 |
| 2a |
Uropods
present and constituting part of a well developed tail fan (even in the
case of crablike species in which the abdomen
is permanently folded against the underside of the thorax)
(picture)(picture) |
3 |
| 2b |
Uropods,
if present, not constituting part of a well developed tail fan |
5 |
| 3a |
Body somewhat lobsterlike, the abdomen
bent under itself but not folded tightly against the underside of the thorax |
4 |
| 3b |
Body crablike, the abdomen
permanently folded against the underside of the thorax |
Superfamily
Galatheoidea:
Family Porcellanidae |
| 4a |
Telson
bent under the abdomen;
not likely to be found in situations shallower than 900 m |
Superfamily Galatheoidea: Family Chirostylidae |
| 4b |
Telson
not bent under the abdomen;
found in shallow water, as well as at considerable depths (picture) |
Superfamily
Galatheoidea:
Family Galatheidae |
| 5a |
Uropods
present, hooklike, and with a rasplike area on each ramus;
abdomen
soft, unsegmented, not folded against the underside of the thorax,
generally twisted (but sometimes straight); living in snail shells,
worm
tubes, or cavities in sponge masses |
6 |
| 5b |
Uropods
absent; abdomen
either firm or soft, segmented or unsegmented, folded against the
underside
of the thorax,
not twisted; not living in snail shells, worm tubes, or cavities
in
sponge masses |
Superfamily
Paguroidea:
Family Lithodidae |
| 6a |
Bases of third maxillipeds
as close together as those of the first 2 pairs; both sexes with paired
pleopods
(male with 2 pairs, female with 1 pair); with 13 pairs of gills; chelipeds
similar and nearly equal (includes 2 species of hermit crabs found
subtidally) |
Superfamily
Paguroidea:
Family Diogenidae |
| 6b |
Bases of third maxillipeds much more widely separated
than those of
the first 2 pairs; either without paired pleopods,
or with paired pleopods
only in the male; with 11 pairs of gills: chelipeds
generally dissimilar and unequal |
7 |
| 7a |
Male without paired pleopods;
female with paired gonopores
(all intertidal hermit crabs and most subtidal hermit crabs belong in
this
group) |
Superfamily
Paguroidea:
Family Paguridae |
| 7b |
Male with paired first and second pleopods;
female with a gonopore
on the left side only (includes a rare hermit crab found in deep water) |
Superfamily Paguroidea: Family Parapaguridae |
