| 1a |
Abdomen
mostly soft (but the telson
may be calcified, and there may be a few other calcified plates), and
not
tightly applied to the underside of the thorax |
2 |
| 1b |
Abdomen
largely or completely covered by calcified plates and tightly pressed
against
the underside of the thorax
(picture) |
6 |
| 2a |
Abdomen
rather thin and flat (picture);
chelipeds
nearly equal (the right cheliped
only slightly larger than the left) (picture);
carapace
and legs with protuberances that resemble scales |
Placetron
wosnessenskii |
| 2b |
Abdomen
thick; chelipeds
decidedly unequal; dactyl
of chelipeds
generally shorter than the palm (propodus)
of the chela;
carapace
and legs without protuberances that resemble scales (they may, however,
have spines, setae, and tubercles |
3 |
| 3a |
Rostrum,
from its base to its tip, studded with stout spines |
Acantholithodes hispidus |
| 3b |
Rostrum
without spines (but it may be setose
and its tip is sharp |
4 |
| 4a |
Cephalothorax
and legs much flattened dorsoventrally and very setose;
upper surface of chelipeds
with spines; anterior margins of most articles
of legs 2-4 with large, flattened spines (the spines are so broad that
they give the margins of the articles
from which they originate a serrated appearance) |
5 |
| 4b |
Cephalothorax
and legs not much flattened dorsoventrally and not especially setose;
upper surface of chelipeds
with prominent, granular tubercles
but without obvious spines; anterior margins of articles
of legs 2-4 without large spines (there are, however, some setae,
as well as tubercles
and small spines) |
Oedignathus
inermis |
| 5a |
Length of rostrum
about twice its width at the base (photo);
upper surface of palm (dactyl)
of right chela
usually with 4 rows of spines running lengthwise |
Hapalogaster
mertensii |
| 5b |
Length of rostrum
less than twice its width at the base; upper surface of right chela
with 3 rows of spines running lengthwise |
Hapalogaster grebnitzkii |
| 6a |
Carapace
with lateral expansions that completely conceal the legs when the
animal
is viewed from above (picture) |
7 |
| 6b |
Carapace
without lateral expansions that completely conceal the legs when the
animal
is viewed from above |
8 |
| 7a |
Propodus
of chelipeds
smooth; rostrum
broader distally than proximally (picture);
abdominal
plates without raised margins (picture) |
Cryptolithodes
sitchensis |
| 7b |
Propodus
of chelipeds
with coarse tubercles;
rostrum
generally broader proximally than distally (picture);
abdominal
plates with raised margins |
Cryptolithodes
typicus |
| 8a |
Outline of carapace,
in dorsal view, similar to that of an equilateral triangle (there are
blunt
or sharp-tipped spines along the lateral margins, however); posterior
half
of dorsal surface of carapace
with a pronounced concavity or semicircular depression (picture) |
9 |
| 8b |
Outline of carapace,
in dorsal view, rounded posterolaterally, not at all similar to that of
an equilateral triangle; posterior half of dorsal surface of carapace
with neither a pronounced concavity nor a semicircular depression |
10 |
| 9a |
Rostrum
divided into 2 blunt lobes; most spines on legs blunt, papillate;
legs with few if any conspicuous setae;
posterior half of carapace
with an extensive concavity, this consisting essentially of 2
depressions,
1 on each side of the midline, the concavity as a whole bordered by
large
tubercles;
lateral margins of carapace
with stout, blunt spines |
Phyllolithodes
papillosus
Brandt, 1849 |
| 9b |
Rostrum
not divided into 2 blunt lobes; spines on legs sharp-tipped; legs with
many long, curved setae
(most of these are longer than the spines); posterior half of carapace
with a semicircular depression, this not bordered by prominent tubercles;
lateral margins of carapace
with sharp-tipped spines |
Rhinolithodes
wosnessenskii
Brandt, 1849 |
| 10a |
Carapace
bumpy, due to the presence of large, granular tubercles;
legs 2-4 stout, not appreciably longer than the width of the carapace |
11 |
| 10b |
Carapace
spiny, but without large tubercles;
legs 2-4 decidedly longer than the width of the carapace |
12 |
| 11a |
Tubercles
on chelipeds
and other legs spinelike; posterior edge of carpus of chelipeds
excavated into a deep sinus
(when this is in apposition to a shallow sinus on the anterior edge of
the carpus of leg 2, a circular hole is formed) |
Lopholithodes
foraminatus
Stimpson, 1862 |
| 11b |
Tubercles
on chelipeds
and other legs mostly rounded and blunt; posterior edge of carpus of chelipeds
not excavated into a sinus |
Lopholithodes
mandtii
Brandt, 1849 |
| 12a |
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| 12b |
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| 13a |
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| 13b |
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| 14a |
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| 14b |
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| 15a |
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| 15b |
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