| 1a |
Body short, grublike, with a horny plate and a tuft of filamentous
gills at the posterior end (Sternaspis scutata in key) |
Sternaspidae:
Sternaspis affinis |
| 1b |
Body generally not grublike, and with neither a horny plate nor a tuft
of filamentous gills at the posterior end |
2 |
| 2a |
Eyes large, bulbous, occupying about half of the dorsal
surface of the prostomium
(prostomium with 4 or
5 antennae; slender worms that taper gradually to the posterior end; strictly
planktonic) |
Alciopidae |
| 2b |
Eyes, if present, not bulbous, and not occupying as much as half of
the dorsal surface of the
prostomium |
3 |
| 3a |
Body transparent, strictly planktonic |
4 |
| 3b |
Body not transparent; mostly benthic, but includes some species whose
sexual individuals swim |
5 |
| 4a |
|
|
| 4b |
|
|
| 5a |
Prostomium conical,
ringed, tapering to a point and tipped with 4 small antennae (pharynxeversible,
its distal end either with
4 hooklike jaws or with 2 large jaws and 2 arcs of smaller jaws) |
6 |
| 5b |
Prostomium, if distinct,
not as described in choice 5a |
7 |
| 6a |
Distal end of everted
pharynx
with 4 hooklike jaws |
Family Glyceridae |
| 6b |
Distal end of everted
pharynx
with 2 large jaws and 2 arcs of smaller jaws (there may also be spines
or chevronlike denticles on the sides of the pharynx) |
Family Goniadidae |
| 7a |
Most of the segments, even when contracted, longer than wide |
8 |
| 7b |
Few if any of the segments, when contracted, longer than wide |
9 |
| 8a |
|
|
| 8b |
|
|
| 9a |
All or much of the dorsal
surface covered by paleae
(these are flattened notosetae,
arranged in transverse
rows), by scalelike elytra
(photo), or by a felt
that consists of hairlike, interwoven notosetae
(photo) |
10 |
| 9b |
Dorsal surface not covered
by paleae,
elytra,
or felt |
14 |
| 10a |
Much of the dorsal surface
covered by brassy or golden paleae
(length generally less than 1 cm) |
Chrysopetalidae |
| 10b |
All or much of the dorsal
surface covered by scalelike elytra
or by long, hairlike notosetae
that are interwoven to form a tough felt (in Aphroditidae, the felt obscures
the elytra underneath it) |
11 |
| 11a |
Elytra obvious, not
covered by felt |
12 |
| 11b |
Elytra hidden by felt
that consists of long, interwoven notosetae
(photo) |
Aphroditidae |
| 12a |
At least some of the neurosetae
compound (divided into 2 units) (look at the neurosetae
with a compound microscope!) |
13 |
| 12b |
All setae simple |
Polynoidae |
| 13a |
Elytra and dorsal
cirri alternating regularly from setiger
5 to the posterior end |
Polyodontidae:
Peisidice aspera |
| 13b |
Elytra and dorsal
cirri alternating only in the anterior part of the body (in the posterior
part, elytra occur on all
segments, and there are no dorsal
cirri) |
Sigalionidae |
| 14a |
Slender capillary
setae distinctly cross-barred, so that they appear to consist of many
units (prostomium with
a pair of grooved palps; body
surface usually papillated) |
15 |
| 14b |
Capillary setae,
if present, not cross-barred |
16 |
| 15a |
|
|
| 15b |
|
|
| 16a |
Head region (the region consisting of the prostomium
and peristomium) with
at least some of the following structures:
1 or more prostomial
antennae (in the Euphrosinidae, which are rare, the antennae are small
and visible only from the ventral side);
a pair of anteroventral palps
on the prostomium;
a pair of dorsal palps
on the peristomium;
1 or more pairs of peristomial
tentacular
cirri;
several to many featherlike radioles
or unbranched filaments that are closely associated with the mouth and
that are used in feeding
(in certain families, there are also specialized
large setae that are used in digging or that form part of a device for
closing the tube when the animal withdraws) |
17 |
| 16b |
Head region without any of the structures listed in choice 15a |
44 |
| 17a |
With a single median
prostomial antenna (no
other head appendages) |
Paraonidae (in part) |
| 17b |
Head appendages not limited to a single median
prostomial antenna |
18 |
| 18a |
Anterior end with a crown of several to many featherlike peristomialradioles,
the complex formed by these resembling a feather-duster (in Manayunkia,
found in fresh and brackish water, there are only a few radioles,
each divided into 2 branches) |
19 |
| 18b |
Anterior end without a crown of featherlike radioles
(there may, however, be simple filaments or other head appendages) |
21 |
| 19a |
Secreting a calcareous tube closed by a funnel-shaped or globular operculum
(this is a modified radiole) |
20 |
| 19b |
Secreting a leathery, parchmentlike, or mucous tube, this not closed
by an operculum |
Sabellidae |
| 20a |
Tube generally sprawling, although its oldest portion may be coiled;
with more than 4 setigers
comprising the thoracic
region |
Serpulidae |
| 20b |
Tube neatly coiled; with only 4 setigers
comprising the thoracic
region |
Spirorbidae |
| 21a |
Notosetae forming
transverse
rows that extend nearly to the midline of the dorsal surface; gills (up
to several pairs on both sides of some segments) situated behind the rows
of notosetae;
prostomial
antennae visible only in ventral view (subtidal; rare) |
Euphrosinidae |
| 21b |
Notosetae not forming
transverse
rows that extend nearly to the midline of the dorsal surface; gills, if
present, usually medial to the notosetae
rather than behind them; prostomial
antennae, if present, visible in dorsal view |
22 |
| 22a |
Prostomium extending
posteriorly on the dorsal surface as an elongated caruncle
(this reaches backward for at least 2 or 3 segments and its texture is
usually different from that of the segments it interrupts (with 3 antennae
and a pair of palps; subtidal;
rare) |
Amphinomidae |
| 22b |
Prostomium not extending
posteriorly on the dorsal surface as an elongated caruncle |
23 |
| 23a |
With several to many more or less equal unbranched tentacles closely
associated with the mouth (in the Apharetidae, the tentacles can be retracted
into the mouth) |
24 |
| 23b |
Without several to many more or less equal tentacles closely associated
with the mouth (there may, however, be 1 or more prostomial
antennae, a pair of prostomialpalps,
a pair of long, grooved dorsal peristomialpalps,
or peristomial tentacular
cirri) |
28 |
| 24a |
Body with a distinct caudal (tail) region that lacks setae
(this may be slender and nearly as long as the rest of the body or it may
be oval and dorsally concave); opening of the tube stopped by an operculum
that consists in part of large, golden setae |
25 |
| 24b |
Body without a distinct caudal region that lacks setae;
opening of the tube not stopped by a definite operculum |
26 |
| 25a |
Caudal region slender and nearly as long as the rest of the body, without
any traces of segmentaton (the caudal region is doubled back on the rest
of the body, so the anus is directed toward the opening of the tube); tube
sprawling, open only at one end (unless eroded), made of sand grains and
bits of shell embedded in a hard, concretelike matrix, permanently affxed
to rocks or shells |
Sabellariidae |
| 25b |
Caudal region short, oval, dorsally concave, consisting of 5 or 6 segments;
tube conical, open at both ends, made of sand grains (photo),
not attached (the worms are mobile and live in sandy or muddy substrata,
using their opercular setae to dig) |
Pectinariidae |
| 26a |
Tentacles around the mouth rather short, smooth or somewhat warty,
capable of being retracted into the mouth; with 2 clusters of simple gills
behind the head region (these gills are stout and may resemble tentacular
cirri of Nereidae and some other polychaetes; they are also likely
to break off) |
Ampharetidae |
| 26b |
Tentacles around the mouth long, threadlike, very extensile, not capable
of being retracted into the mouth; with 1 or more pairs of simple or branched
gills arising on successive segments behind the head region |
27 |
| 27a |
All or most thoracic
segments with soft, light-colored pads on the ventral surface; neuropodialuncini
of the thoracic region,
like those of the abdominal region, with short handles |
Terebellidae |
| 27b |
Thoracic segments without
soft pads on the ventral surface; neuropodialuncini
of the thoracic region with
long handles |
Trichobranchidae |
| 28a |
Without prostomial
antennae or peristomial tentacular
cirri; with a pair of long palps
(these are usually grooved) arising from the prostomium
or dorsal side of the peristomium
(photo) |
29 |
| 28b |
With 1 or more (usually at least 2) prostomial
antennae and sometimes with a pair of prostomialpalps
(photo) and/or 1 or
more pairs of peristomialtentacular
cirri |
34 |
| 29a |
Peristomial palps
warty for all or most of their length, even when extended; head region
flattened, resembling a spatula; gills absent |
Magelonidae |
| 29b |
Peristomial palps
not warty, at least when extended; head region not flattened; gills sometimes
present |
30 |
| 30a |
Body consisting of 2 or 3 regions, each with distinctive parapodia |
31 |
| 30b |
Body not consisting of 2 or 3 regions (even if the anterior portion
is slightly different from the posterior portion, the parapodia
of both portions are similar) |
32 |
| 31a |
|
|
| 31b |
|
|
| 32a |
Notopodia without
setae
other than aciculae |
Apistobranchidae |
| 32b |
Notopodia with setae
as well as aciculae |
33 |
| 33a |
Several to many segments with long, filamentous gills |
Cirratulidae (in part)
(Photo) |
| 33b |
Gills usually present (absent, however, in Spiophanes), arising
from notopodia of most
segments, but not filamentous (they are usually not more than several times
as long as wide, and in some species they are pinnate) |
Spionidae |
| 34a |
Prostomium with
a pair of palps (these usually
originate anteroventrally; and are often divided into 2 units; when they
originate more or less anterolaterally [as in Protodorvillea, Dorvilleidae],
they are reduced to small papillae;
do not confuse any of the 4 prostomial
antennae of Nephtyidae with palps |
35 |
| 34b |
Prostomium without
palps |
43 |
| 35a |
Prostomialpalps
differentiated into 2 units (the distal
unit may be small and nipplelike, however) |
36 |
| 35b |
Prostomialpalps
not differentiated into 2 units |
39 |
| 36a |
All setae simple (make
sure by looking at them with a compound microscope); distal
unit of palps usually small
and nipplelike |
Pilargiidae |
| 36b |
Compound setae present;
distal
unit of palps usually substantial,
even if smaller than the proximal unit |
37 |
| 37a |
With 2 prostomialantennae
(antennae are absent, however,
in Micronereis); pharynx,
when everted, clearly consisting
of 2 portions, with a pair of stout jaws on the distal
portion and usually with conical teeth on one or more areas of both portions
(to induce eversion of the
pharynx,
apply firm pressure just behind the head region) (proximal
unit of the prostomialpalps
much larger than the
distal
unit) |
Nereidae |
| 37b |
With 2 or 3 prostomialantennae;
pharynx
not divided into 2 portions, and not with the arrangement of jaws and teeth
described in choice 37a (there may, however, be a pair of ventral mandibles
and rows of toothed dorsal plates that form maxillae) |
38 |
| 38a |
With 2 or 3 prostomial
antennae; peristomium
with 2-8 pairs of tentacular
cirri; distal unit of prostomial
palps usually longer than the proximal unit; pharynx
(in our species) without jaws |
Hesionidae (in
part) |
| 38b |
With 2 prostomial
antennae; peristomium
without tentacular
cirri; distal unit of prostomial
palps much shorter than the proximal unit; pharynx
with a pair of ventral mandibles and rows of toothed dorsal plates that
form maxillae. |
Dorvilleidae (in part) |
| 39a |
Peristomium without
tentacular
cirri; with 2 prostomial
antennae (pharynx with
a pair of ventral mandibles
and rows of toothed dorsal plates that form maxillae;
prostomialpalps
sometimes very small [Ophryotrocha, which has only a few setigers],
sometimes prominent [Protodorvillea] |
Dorvilleidae (in part) |
| 39b |
Peristomium with
at least 1 pair of tentacular
cirri (photo); with
2 or more prostomial
antennae |
40 |
| 40a |
Pharynx (in our species)
without jaws or teeth (with 2 or 3 prostomial
antennae; with 2-8 pairs of peristomialtentacular
cirri) |
Hesionidae (in
part) |
| 40b |
Pharynx with jaws or
teeth |
41 |
| 41a |
Prostomium with
3 antennae; usually with 4 eyes (sometimes 2 or 6); pharynx
with a single large tooth or a crown of small teeth, or both |
Syllidae |
| 41b |
Prostomium with
2, 5, or 7 antennae; if eyes are present, there are usually 2; pharynx
with a pair of ventral mandibles
and 2 or more rows of toothed dorsal pieces that form maxillae |
42 |
| 42a |
Prostomium with
7 antennae (the 5 arising near the posterior margin of the prostomium
are usually much larger than the 2 arising near the anterior margin) |
Onuphidae |
| 42b |
Prostomium with
5 antennae (photo) (prostomialpalps
stout, globular, often indistinctly demarcated from the prostomium) |
Eunicidae |
| 43a |
Prostomium with
4 small antennae (prostomialpalps
stout, globular, often indistinctly demarcated from the prostomium;
usually without eyes (but eyes present in some species) |
Nephtyidae |
| 43b |
Prostomium with
4 or 5 antennae; these not arranged as described in choice 43a; usually
with eyes; with 2-4 pairs of tentacular
cirri on the peristomium |
Phyllodocidae |
| 44a |
With not more than 15 segments when mature; most segments indistinct;
length
less than 1 cm |
45 |
| 44b |
With more than 15 segments; most segments distinct; length generally
greater than 1 cm |
46 |
| 45a |
|
|
| 45b |
|
|
| 46a |
Prostomium indistinct;
surface of body with prominent papillae,
many of which are almost globular |
Sphaerodoridae |
| 46b |
Prostomium distinct;
even if small; if papillae are present on the body, they are not almost
globular |
47 |
| 47a |
Notopodial gills
long and threadlike; with several long, grooved filaments arising from
the dorsal surface of one
of the first few setigers |
Cirratuladae (in part) |
| 47b |
Notopodial gills,
if present, not long and threadlike; without any grooved filaments arising
from the dorsal surface
of one of the first few setigers
(there may, however, be a single filament growing out of setiger
2 or 3) |
48 |
| 48a |
With a single threadlike filament growing out of the dorsal surface
of setiger 2 or 3 |
Cossuridae |
| 48b |
Without a single threadlike filament growing out of the dorsal surface
of setiger 2 or 3 |
49 |
| 49a |
With several pairs of large, bushy gills in the middle third of the
body |
Arenicolidae |
| 49b |
Wthout several pairs of large, bushy gills in the middle third of the
body (but small, usually simple gills may be present in that region, or
there may be conspicuous bushy gills near the anterior end) |
50 |
| 50a |
|
|
| 50b |
|
|
| 51a |
|
|
| 51b |
|
|
| 52a |
|
|
| 52b |
|
|
| 53a |
|
|
| 53b |
|
|
| 54a |
|
|
| 54b |
|
|
| 55a |
|
|
| 55b |
|
|
| 56a |
|
|
| 56b |
|
|
