| 1a |
Pleon
with 4 or 5 visible free pleonites,
plus the pleotelson |
2 |
| 1b |
Pleon
with not more than 3 visible or partly free pleonites,
plus the pleotelson
(pleonite
1 is hidden beneath
pereonite 7) |
15 |
| 2a |
Uropod
with both rami
well developed, these usually lamellar
in form (photo);
not capable of rolling up into a ball; not boring in wood or kelps |
5 |
| 2b |
Uropod
with a rudimentary
and more or less clawlike exopodite;
capable of rolling up into a ball; boring in wood or kelps |
3 |
| 3a |
Boring in holdfasts of kelps; incisor process of mandibles
with neither a rasplike nor a filelike specialization |
Limnoria (Phycolimnoria)
algarum |
| 3b |
Boring in wood; incisor process of right mandible
with filelike ridges, that of the left mandible
with scales that form a rasp |
4 |
| 4a |
Dorsal
surface of pleotelson
without tubercles,
but with a slight median ridge that bifurcates
posteriorly |
Limnoria
(Limnoria)
lignorum |
| 4b |
Dorsal
surface of pleotelson
with 3 small tubercles |
Limnoria (Limnoria)
tripunctata |
| 5a |
None of the pereopods
with large, hooklike dactyls
for attachment to fishes (but there may be small hooks) (photo) |
6 |
| 5b |
Pereopods
1-3, or all pereopods,
with large, hooklike dactyls
for attachment to fishes |
9 |
| 6a |
Posterior border of telson
fringed by about 26 short, simple setae;
anterior edge of cephalon
with an inconspicuous rostrum;
on rocky shores, among mussels, etc. |
Cirolana harfordi |
| 6b |
Posterior border of telson
fringed by long, plumose setae;
anterior edge of cephalon
with an obvious spatulate
rostrum;
on sandy shores |
7 |
| 7a |
Telson
broadly rounded or almost truncate
posteriorly |
Excirolana linguifrons |
| 7b |
Telson
somewhat angular posteriorly |
8 |
| 8a |
Tip of angular portion of telson
rather sharply pointed |
Excirolana
kincaidi |
| 8b |
Tip of angular portion of telson
rounded |
Excirolana vancouverensis |
| 9a |
Pereopods
1-3 prehensile,
with hooklike dactyls
for attachment to fishes (but some species are free-living part of the
time) |
10 |
| 9b |
All pereopods
prehensile,
with hooklike dactyls
for attachment to fishes (photo) |
14 |
| 10a |
Flagellum
of antenna 1 with numerous articles;
propodus
of prehensile
pereopods
not expanded |
Aega symmetrica |
| 10b |
Flagellum
of antenna 1 with only 4 to 6 articles;
propodus
of prehensile
pereopods
expanded along the inner margin |
11 |
| 11a |
Cephalon
drawn out into a spatulate
rostrum,
this flanked on both sides by a small projection |
Rocinela tridens |
| 11b |
Cephalon
drawn out into a more or less triangular rostrum,
but the tip of this may be truncated |
12 |
| 12a |
Tip of rostrum
pointed |
Rocinela belliceps |
| 12b |
Tip of rostrum
truncated |
Rocinela
propodialis |
| 13a |
|
|
| 13b |
|
|
| 14a |
|
|
| 14b |
|
|
| 15a |
Not capable of rolling up into a ball; pereopod
1 subchelate in both sexes, pereopod
2 subchelate
in the male |
Lironeca californica |
| 15b |
Capable of rolling up into a ball; none of the pereopods
subchelate
in either sex |
16 |
| 16a |
Pleotelson
either trilobed or deeply notched at the apex |
17 |
| 16b |
Pleotelson
neither trilobed nor deeply notched at the apex |
20 |
| 17a |
|
|
| 17b |
|
|
| 18a |
|
|
| 18b |
|
|
| 19a |
|
|
| 19b |
|
|
| 20a |
Two or 3 of the visible pleonites
(these are free laterally, but not along the midline) reaching the
lateral
margins; pleopods
without respiratory folds |
21 |
| 20b |
Only 1 pleonite
reaching the lateral margins; pleopods
4 and 5 with respiratory folds |
23 |
| 21a |
Three pleonites
reaching the lateral margins |
22 |
| 21b |
Two pleonites
reaching the lateral margins (the third visible pleonite
is "crowded out")(in decidedly brackish or nearly fresh water) |
Gnorimosphaeroma insulare |
| 22a |
Basal articles
of antennae 1 touching each other in the midline |
Gnorimosphaeroma noblei |
| 22b |
Basal article
of antennae 1 distinctly separated from one another by a short rostrum
(common intertidal species, usually under rocks, but also found on
floats
and pilings and in various other situations) |
Gnorimosphaeroma
oregonensis |
| 23a |
|
|
| 23b |
|
|
| 24a |
|
|
| 24b |
|
|
| 25a |
|
|
| 25b |
|
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