| 1a |
Without prostomial
antennae; prostomialpalps
small, inconspicuous |
Micronereis nanaimoensis |
| 1b |
With prostomial
antennae; prostomialpalps
conspicuous |
2 |
| 2a |
With 3 pairs of tentacular
cirri on the peristomium;
notopodia
without any setae other
than the
aciculae [previously
identified as Namanereis quadraticeps (Blanchard, 1849), which probably
does not occur in the northern hemisphere] |
Lycastopsis sp. |
| 2b |
With 4 pairs of tentacular
cirri on the peristomium;
notopodia
with setae in addition
to the aciculae |
3 |
| 3a |
Ventral cirrus
of parapodia of anterior
part of the body divided near the base into 2 branches |
Ceratocephale loveni |
| 3b |
Ventral cirrus
of all parapodia
simple |
4 |
| 4a |
Tentacular
cirri of peristomium
constricted into several units |
Nicon moniloceras |
| 4b |
Tentacular
cirri of peristomium
not constricted into several units |
5 |
| 5a |
Segment 2 (following peristomium)
enlarged, projecting anteriorly as a collarlike structure around the peristomium
(commensal with large, subtidal hermit crabs) |
Cheilonereis cyclurus |
| 5b |
Segment 2 not enlarged and not forming a collarlike structure around
the peristomium |
6 |
| 6a |
Most of the paragnaths
on the evertedpharynx
conical |
7 |
| 6b |
At least some of the paragnaths
on the evertedpharynx
elongated transversely,
crowded into comblike configurations, or otherwise deviating from a conical
form |
18 |
| 7a |
Notopodia of
posterior portion of the body with homogomphfalcigeroussetae |
8 |
| 7b |
Notopodia of
posterior portion of the body without homogomphfalcigeroussetae |
15 |
| 8a |
Distal ring of evertedpharynx
without paragnaths |
Nereis (Eunereis) wailesi |
| 8b |
Distal ring of evertedpharnx
with paragnaths |
9 |
| 9a |
Upper ligule of notopodia
of posterior region of the body much larger than the lower ligule |
10 |
| 9b |
Upper ligule of notopodia
of the posterior region of the body not obviously larger than the lower
ligule |
12 |
| 10a |
Upper ligule of notopodia
of the posterior region of the body strap-shaped (photo) |
Nereis vexillosa |
| 10b |
Upper ligule of notopodia
of the posterior region of the body not strap-shaped |
11 |
| 11a |
|
|
| 11b |
|
|
| 12a |
|
|
| 12b |
|
|
| 13a |
|
|
| 13b |
|
|
| 14a |
|
|
| 14b |
|
|
| 15a |
Proximal ring of
evertedpharynx
usually without
paragnaths,
or with only a few on area VII |
Nereis (Ceratonereis) paucidentata |
| 15b |
Proximal ring of
evertedpharynx
usually with
paragnaths
in all areas, although they may be absent in area I or V |
16 |
| 16a |
Dorsal ligule of
parapodia
not obviously larger than the ventral ligule
(hermaphroditic
and ovoviparous;
found in estuarine situations and in fresh water) |
Nereis (Neanthes) limnicola |
| 16b |
Dorsal ligule of
parapodia
leaflike and much larger than the ventral ligule |
17 |
| 17a |
Areas VII and VIII of evertedpharynx
with paragnaths arranged
in a band that consists of 4 or more rows [Nereis (Neanthes)
brandti
in key] |
Neanthes brandti |
| 17b |
Areas VII and VIII of evertedpharynx
with paragnaths arranged
in 2 or 3 irregular rows (paragnaths
may be absent in area I) [Nereis (Neanthes)
virens
in key] |
Neanthes virens |
| 18a |
Area VI of evertedpharynx
with a large,
transversely
elongated
paragnath |
Perinereis monterea |
| 18b |
Paragnaths on
area VI of evertedpharynx
neither large nor transversely
elongated, but compactly arranged in such a way that they form a nearly
comblike configuration (common in sediment and among Ulva and other
green algae in bays) |
Platynereis bicanaliculata |