| 1a |
Pereopod
3 chelate;
epimera
of abdominal
segment 2 overlapped by those of segment 1; abdomen
without a sharp bend; primarily oceanic and not likely found except in
deep water |
2Suborder
Dendrobranchiata:
Prawns |
| 1b |
Pereopod
3 not chelate;
epimera
of abdominal
segment 1 overlapped by those of segment 2; abdomen
with a sharp bend in some families but not in others; includes many
littoral
and shallow-water species as well as some that are mostly restricted to
deep water |
5Suborder Pleocyemata,
Infraorder
Caridea:
True shrimp |
| 2a |
Pereopods
1-3 obviously chelate.
Usually have a long rostrum
which is much longer than the antennal
scales |
3 Family
Penaeidae |
| 2b |
Pereopod
1 not chelate,
and pereopods
2 and 3 with small, inconspicuous
chelae.
Usually have only a short, stubby rostrum |
4 Family
Sergestidae |
| 3a |
Curved transverse
grooves on the carapace
are interrupted by the median
ridge; telson
with 2 pairs of stout, movable spines |
Bentheogennema borealis
(Rathbun, 1902) |
| 3b |
Curved transverse
grooves on the carapace
not interrupted by the median
ridge; telson
with only 1 pair of stout, movable spines |
Bentheogennema
burkenroadi
Krygier & Wasmer, 1975 |
| 4a |
With a prominent spine on the dorsal part of the carapace
just behind each eye, and with a similar spine on both sides of the carapace
at a slightly more posterior level |
Eusergestes
similis
(Hansen, 1903) |
| 4b |
Without the spines described above |
Sergia tenuiremis
(Kroyer, 1855) |
| 5a |
Pereopods
1-5 with exopodites
(mostly midwater and deep benthic species) (photo) |
6 |
| 5b |
None of the pereopods
with exopodites |
7 |
| 6a |
Pereopods
1 and 2 longer and obviously more stout than the others |
Family
Pasiphaeidae |
| 6b |
Pereopods
1 and 2 shorter than the others and not obviously more stout (mostly
midwater
and deep benthic species) |
Family
Oplophoridae |
| 7a |
Pereopod
1 subchelate
(picture);
carpus
of pereopod
2 not subdivided into several units (picture) |
Family
Crangonidae |
| 7b |
Pereopod
1 not subchelate; carpus of pereopod
2 subdivided into several units |
8 |
| 8a |
Carpus of pereopod
2 subdivided into more than 7 units; rostrum
prominent and with movable dorsal spines |
Family
Pandalidae |
| 8b |
Carpus of pereopod
2 divided into 3-7 units; rostrum,
if present, without movable dorsal spines |
9 |
| 9a |
Rostrum
absent (picture);
eyes at least partly covered dorsally by the carapace
(picture) |
Family
Alpheidae |
| 9b |
Rostrum
present; eyes not covered dorsally by the carapace |
Family
Hippolytidae
("broken-back
shrimp") |