| 1a |
Body mass
or colony has the appearance of an
amorphous mass. May be hard, spongy, or gelatinous. May be a thin or
thick
crust or may be erect. Often have holes, which may be either single,
paired,
or scattered and may be on the tips of elevations on the mass. |
2 |
| 1b |
Body mass
or colony variable, but does not have
the appearance of an amorphous mass. |
3 |
| 2a |
Mass is
soft or hard and may contain calcium
or glass spicules.
Larger
holes, if present, do not occur in pairs. |
Phylum
Porifera: Sponges |
| 2b |
Mass is
gelatinous or leathery and does not
contain spicules. Holes are in pairs. A basketlike network may or may
not
be visible inside. |
Phylum
Chordata, Subphylum Urochordata, Class Ascidiacea: Tunicates |
| 3a |
Body is
gelatinous and the species is pelagic |
4 |
| 3b |
The body
is not gelatinous or the species is
not pelagic |
11 |
| 4a |
Radially
symmetrical. Have one or more swimming
bells that contract for propulsion, or swim by beating rows of comblike
cilia. |
5 |
| 4b |
Not
radially symmetrical |
8 |
| 5a |
Swim by
beating rows of comblike cilia |
Phylum
Ctenophora |
| 5b |
Swim by
contracting one or more gelatinous bells,
but not by beating rows of comblike cilia. Contain stinging cnidocytes. |
6 |
| 6a |
Solitary medusae
which are often large, often colored (red, yellow, orange, and pink are
common colors). The margin of the bell is often scalloped into lappets.
No velum
is present. Manubrium
is drawn out into 4 or 8 frilly oral
arms. The gut may be in the form of four pouches lined with
colorful
gonads, or may have extensive gastrovascular canals. Note: If attached
by the exumbrella,
or if
a stalk protrudes from the exumbrella, see choice 11a, Order
Stauromedusae) |
Class
Scyphozoa, Order Semaestomae |
| 6b |
Solitary medusae
or a colony of swimming bells. Not often more than 6 cm in diameter.
Usually
not colored (may have white). The margin of the bell is not scalloped
into
lappets but often has a velum.
Mouth is in the form of a tubelike manubrium
but is not drawn out into frilly oral
arms, though its margins may be lobed or frilly. Gut is a
small central
cavity with (usually four) radiating canals and a ring canal near the
margin
of the umbrella. A swollen tentacular bulb occurs at the junction of
each
radial canal with the ring canal. Colonial forms consist of a string of
swimming bells, tentacles, and perhaps a gas-filled float |
7 [Class Hydrozoa] |
| 7a |
Solitary medusae |
Hydrozoan
medusae |
| 7b |
Colonial |
Class
Hydrozoa, Order Siphonophora |
| 8a |
Swim by
beating comblike rows of cilia |
Phylum
Ctenophora |
| 8b |
Do not
swim by beating comblike rows of cilia |
9 |
| 9a |
Body
barrel-like. Take water in through an anterior
buccal or incurrent siphon, filter it through an internal pharyngeal
basket, and pump it out a posterior atrial
or excurrent siphon |
Salp or
Doliolid |
| 9b |
Do not
filter water by pumping it through a
buccal
siphon, pharyngeal
basket, and atrial
siphon |
10 |
| 10a |
Laterally
compressed, the foot is a ventral
fin. Swim upside-down. Have a shell which may be large or small |
Phylum
Mollusca, Class Gastropoda, Subclass
Prosobranchia, Order Mesogastropoda, Superfamily Heteropoda: Heteropods |
| 10b |
Foot has
two fins projecting laterally and perhaps
anteriorly or ventrally, used either for rowing or for sculling in a
figure
eight. May or may not have a shell |
Phylum
Mollusca, Class Gastropoda, Subclass
Opisthobranchia: Shelled or naked pteropods |
| 11a |
Radially
symmetrical, a jellyfish which is attached
to the substrate by a stalk from its exumbrella |
Phylum
Cnidaria, Class Scyphozoa, Order Stauromedusae |
| 11b |
Not a
jellyfish |
12 |
| 12a |
A modified
polyp which floats on the ocean surface.
Has a chitinous sail. Normally oceanic but may be blown ashore during
storms |
Phylum
Cnidaria, Class Hydrozoa, Velella velella |
| 12b |
Not a
modified, floating polyp with a sail |
13 |
| 13a |
Growth
form is a cuplike polyp, either solitary
or as a colony |
14 [Phylum Cnidaria] |
| 13b |
Growth
form is not as a polyp |
20 |
| 14a |
Small
polyps (usually less than 1 mm), a few
solitary but mostly colonial due to budding. Colonies may be
arborescent
(bushlike) or pinnate (featherlike). Not usually brightly colored.
Different
polyps in the colony are often polymorphic (specialized for different
functions).
Polyps are usually at least partially surrounded by a proteinaceous
coat
called a perisarc. |
Class
Hydrozoa, Polyps of Order Hydroida |
| 14b |
Polyps
large and solitary, or if small, not
in an arborescent or pinnate colony surrounded by a protein perisarc |
15 |
| 15a |
Polyps
have eight pinnate tentacles (with featherlike
side branches) |
Class
Anthozoa, Subclass Alcyonaria (Octocorallia) |
| 15b |
Tentacles
not eight in number, and not pinnate |
16 |
| 16a |
Polyps
larger than 1 mm in diameter, with no
calcified skeleton. |
17 |
| 16b |
Polyps
with a calcified skeleton, and may be
1 mm or less in diameter |
19 |
| 17a |
Solitary
polyps–not connected by
a stolon |
18 |
| 17b |
Colonial
polyps, connected by a stolon |
Order
Zoanthidea:
Zoanthids
|
| 18a |
Tentacles
taper to a point, no knoblike tips |
Order
Actiniaria: Sea Anemones |
| 18b |
Tentacles
end with knoblike tips |
Order
Corallimorpharia:
Corynactis californica |
| 19a |
Solitary
polyps, diameter greater than 2 mm,
with mesenteries and tentacles in multiples of 6. |
Order
Scleractinia: True corals |
| 19b |
Polyps
colonial, polyp diameter may be less
than 2 mm. Mesoglea is acellular. Usually purple, calcified colonies of
many polyps |
Class
Hydrozoa, Order Stylasterina:
Hydrocorals |
| 20a |
Shaped
like a round or flattened worm or slug;
with a soft exterior (includes animals that may be living in a
cemented,
calcified, or chitinous tube and soft pelagic worms) |
21 |
| 20b |
Does not
have a wormlike or sluglike shape and
a soft exterior |
40 |
| 21a |
Permanently
attached to a substrate; exterior
is a leathery tunic with two openings, the incurrent (buccal) and
excurrent
(atrial) siphon |
Phylum
Chordata, Subphylum Urochordata, Class Ascidiacea: Solitary Ascidians |
| 21b |
Not
permanently attached to a substrate nor
with a buccal and atrial siphon |
22 |
| 22a |
Small,
flattened, predatory pelagic worms with
lateral fins and long setae for jaws. |
Phylum
Chaetognatha |
| 22b |
Not small,
flattened predatory pelagic worms
with lateral fins and long setae for jaws. |
23 |
| 23a |
Bodies are
clearly segmented–with
repeating units |
24Phylum
Annelida |
| 23b |
Bodies are
not segmented with repeating units |
25 |
| 24a |
Have
parapodia on at least some body segments;
parapodia usually have many bristly setae. May be freeliving,
burrowing,
or live in a tube |
Class
Polychaeta |
| 24b |
Have no
parapodia. Rounded worms with multiple
segments and a few setae |
Class
Oligochaeta |
| 25a |
Flat worms
with a blind gut; the only opening
to which is a pharynx which is generally midventral. The gut has many
side
pockets, often visible from the outside |
Phylum
Platyhelminthes, Class Turbellaria, Order Polycladida:
Polyclad
Flatworms |
| 25b |
Not flat
worms with a blind gut |
26 |
| 26a |
Feed by
means of a specialized circle of tentacles
or ciliated ridges (lophophore) near the mouth |
27 |
| 26b |
Do not
have a specialized circle of feeding
tentacles or lophophore near the mouth |
28 |
| 27a |
Deposit or
suspension feeders. Feed with a specialized
circle of feeding tentacles which are held out in the water or scraped
along the sediment, then stuffed into the mouth. Usually have tube
feet,
which may be in five longitudinal rows along the body. |
Phylum
Echinodermata, Class Holothuroidea: Sea Cucumbers |
| 27b |
Suspension
feeders. Worms which live in a chitinous
tube and feed by extending a ciliated ridge or lophophore up into the
water. |
Phylum
Phoronida |
| 28a |
Flattened,
predatory ribbon worms, often brightly
colored, which capture prey using an eversible proboscis which may have
fangs |
Phylum
Nemertea: Ribbon worms |
| 28b |
Not
flattened, predatory worms which hunt with
an eversible proboscis |
29 |
| 29a |
Round
worms which burrow in soft sediments,
or live in crevices in rock or coral. Have a large, extensible
projection
on the head which may or may not be completely retractable into the
trunk. |
30 |
| 29b |
Not round
worms living in sediments and with
a large, retractable projection on the head |
31 [Phylum
Mollusca, Class Gastropoda, (in part)] |
| 30a |
Anterior
structure is a flattened proboscis
whose edges fold ventrally to form a gutter which leads to the mouth.
Proboscis
cannot be completely retracted into the trunk. Trunk has two large,
hooked
setae on the ventral side near the anterior end |
Phylum
Echiura |
| 30b |
Anterior
structure is a rounded introvert, which
is greatly extensible and can be completely retracted into the trunk.
Mouth
is at the anterior end of the introvert. Does not have two hooked setae
on the trunk |
Phylum
Sipuncula: Peanut worms |
| 31a |
Pelagic,
with foot extensions into a ventral
fin or lateral paddles for swimming. May or may not have a shell |
32 |
| 31b |
Most not
pelagic. Have a ventral foot but it
does not extend into a ventral fin or lateral paddles for swimming. |
34 |
| 32a |
Elongated,
twisted cylindrical gastropod mollusk,
with a ventral extension on the foot which serves as a fin for
swimming.
Swims upside down and has a reduced shell |
Subclass
Prosobranchia, Order Mesogastropoda,
Superfamily Heteropoda: Heteropods |
| 32b |
Pelagic
gastropod with a foot with lateral extensions
used for rowing |
33 Subclass Opisthobranchia
(in part):
Pteropods |
| 33a |
Have a
shell |
Order
Thecosomata: Shelled pteropods: Limacina
helicina |
| 33b |
Do not
have a shell. Part of the mantle or foot,
just behind the head, is elaborated into flipperlike structures for
swimming |
Order
Gymnosomata: Naked pteropods |
| 34a |
Rhinophores
absent |
Order
Sacoglossa (in part) |
| 34b |
Rhinophores
present |
35 |
| 35a |
Clavus of
rhinophores perfoliate, or with longitudinal
ridges, or with vertical pinnate plumes beside the clavus |
Order
Nudibranchia (in part) |
| 35b |
Clavus of
rhinophores smooth and not distinct
from the stalk (in cross-section, the rhinophores may be solid or
rolled
into cylinders) |
36 |
| 36a |
Rhinophores
retractile into sheaths |
Order
Nudibranchia (in part) |
| 36b |
Rhinophores
not retractile into sheaths |
37 |
| 37a |
Dorsum
with elongate outgrowths, such as cerata |
38 |
| 37b |
S
Dorsum without elongate outgrowths |
Order
Sacoglossa (in part) |
| 38a |
Rhinophores
rolled into cylinders |
Order
Sacoglossa (in part) |
| 38b |
Rhinophores
solid in cross-section |
39 |
| 39a |
Anus on
the midline, just posterior to the rhinophores |
Order
Sacoglossa (in part) |
| 39b |
Anus on
the right side of the body |
Order
Nudibranchia (in part) |
| 40a |
Less than
1 mm long, meiofauna (between sand
grains or in mud), with a spiny cuticle divided into plates. With an
anterior
protrusible head. |
Phylum
Kinorhyncha |
| 40b |
Not an
animal less than 1 mm long, with a spiny
cuticle divided into plates and an anterior protrusible head. |
41 |
| 41a |
Body
largely or entirely enclosed within two
external “valves� or shells which
hinge together on one side. Neither body nor any appendages are
segmented. |
42 |
| 41b |
Body is
not enclosed within two external valves
which hinge together on one side. Body or appendages may or may not be
segmented |
43 |
| 42a |
Body is
composed of a large gill used for filter
feeding, a foot which can protrude from the shell, a visceral mass, and
a mantle which secretes the shell. Foot is used for digging or for
secreting
proteinaceous byssal threads which are used for attachment to the
substrate.
Valve opening is limited by muscle action. Do not attach to the
substrate
by means of a fleshy stalk which protrudes from the shell. |
Phylum
Mollusca, Class Bivalvia |
| 42b |
Valve
opening is limited by muscle action or
by interlocking parts of the valves (in which case the valves cannot be
opened by more than a few degrees without breaking them). Filter feed
using
a lophophore. Do not have large, separate gills nor a protrusible foot.
Attached to the substrate by a fleshy stalk which protrudes from one of
the valves. |
Phylum
Brachiopoda:
Lampshells
|
| 43a |
Pelagic,
with a tadpole-like body which secretes
a gelatinous "house" used for filter feeding. Currents through the
house
are generated by beating of the tail |
Phylum
Chordata, Subphylum Urochordata, Class
Larvacea:
Larvaceans |
| 43b |
Not
pelagic and tadpole-shaped, living in a
gelatinous house |
44 |
| 44a |
Body
segmented. Covered with an exoskeleton,
and having jointed legs |
45 [Phylum Arthropoda] |
| 44b |
Body
unsegmented |
59 |
| 45a |
Spider-like,
with long-legs extending from a
small cephalothorax and with sucking mouth parts. No antennae but have
a proboscis. Either large and found in deep benthic habitats or less
than
1 cm and usually found on sea anemones |
Class
Pycnogonida |
| 45b |
Have jaws
instead of sucking mouth parts. Have
antennae. Not usually spider-like |
46 |
| 46a |
Small
(< 1 cm long) as adults, pelagic. No
special gills but legs are leaf-like appendages used both for swimming
and for respiration |
Class
Branchiopoda |
| 46b |
Small or
large, but do not breathe with leaf-like
appendages used both for swimming legs and for respiration |
47 |
| 47a |
Small
(most < 1 mm) as adults (except for
some bizarre parasitic forms). Short, cylindrical body. One median
naupliar
eye but no compound eyes. Abdomen has no appendages, except that the
anal
segment is forked into two “caudal rami�.
Long, conspicuous, uniramous first antennae |
Class
Copepoda: Copepods |
| 47b |
Not with a
small, cylindrical body, one median
naupliar eye, and caudal rami |
48 |
| 48a |
Permanently
cemented to substrate as adults.
Either surrounded by six calcareous plates which are cemented to the
substrate
or attached by a fleshy stalk and covered with a set of plates which do
not cement to the substrate. Feed by beating filamentous legs or
holding
them in the current |
49 [Class Cirripedia,
Order Thoracica: Barnacles] |
| 48b |
Not
permanently cemented to the substrate as
adults. |
50 |
| 49a |
Surrounded
by six calcareous plates which are
cemented to the substrate |
Suborder
Balanomorpha: Acorn Barnacles |
| 49b |
Attached
by a fleshy stalk; body is surrounded
by plates which are not cemented to the substrate |
Suborder
Lepadomorpha: Goose Barnacles |
| 50a |
Possess a
cephalothorax; the head and several
or all the thoracic segments are fused to one another at least dorsally
by a carapace. Most or all individual thoracic segments are not visible
from the dorsal side |
51 |
| 50b |
The head
and thoracic segments are not fused
together with a carapace. The individual thoracic segments are visible
from the dorsal side |
57 |
| 51a |
Shrimplike,
lobster-like, or crab-like; commonly
found. If shrimplike, the dorsal carapace is attached to all thoracic
segments.
Females carry eggs on the thoracic or abdominal legs, but do not carry
them within a special thoracic pouch (marsupium) formed by inner
branches
from the legs. |
52 |
| 51b |
Shrimp-like,
usually small (intertidal species
are usually < 3 cm long), and not commonly found. Dorsal
carapace not
attached to all the thoracic segments, though it may overlap them.
Females
carry eggs within a special thoracic marsupium formed by the inner
branches
of the legs |
56 |
| 52a |
Crablike:
The thorax is covered with a wide
carapace, the first pereopod is chelate (a pincer), the abdomen is held
tucked tightly under the thorax and has no uropods. All ten legs are
easily
visible and functional for locomotion. The eyes are usually lateral to
the large second antennae. |
Infraorder
Brachyura: True crabs |
| 52b |
Crablike
or shrimplike, but if crablike the
fifth pair of legs are reduced or turned upward and eyes are medial to
the large second antennae. |
53 |
| 53a |
Clearly
shrimplike or lobster-like: Thorax is
laterally compressed and usually longer than wide; abdomen is extended
behind the thorax. |
54 |
| 53b |
Crablike,
with a wide, depressed thorax or somewhat
shrimplike, with a globular or slightly elongated thorax. Fifth
pereopod
(walking leg) reduced or turned upward, not useful for walking. Abdomen
may be held under the thorax, but more loosely than in the true crabs;
may be extended to the rear somewhat like a shrimp, or may be soft and
twisted (in hermit crabs). Abdomen usually has uropods. |
Infraorder
Anomura: Porcelain crabs, Hermit crabs, Lithodid crabs, Squat lobsters |
| 54a |
Shrimplike.
Gills are dendrobranchiate (tree-shaped,
with two main branches from the main stalk and many compact side
branches).
First three pairs of legs are chelate but not with enlarged chelipeds.
Pleuron of second abdominal segment does not overlap that of the first
and third segment. Females do not brood their eggs. |
Suborder
Dendrobranchiata: Penaeid prawns |
| 54b |
Shrimplike
or lobster-like. Gills are phyllobranchiate
(a series of stacked hollow plates) or trichobranchiate (a series of
hollow
tubes attached to a common stalk). Females usually brood their eggs. |
55 |
| 55a |
Shrimplike:
Abdomen is as high or higher than
it is wide. Pleuron of second abdominal segment overlaps that of the
first
and third segment. First three pairs of pereopods (walking legs) are
either
chelate or subchelate and the first or second pair usually has enlarged
chela (though often much smaller than those seen on crabs).
Phyllobranchiate
gills. |
Infraorder
Caridea: True shrimp |
| 55b |
Lobster-like:
Abdomen is wider than it is high.
Trichobranchiate gills. First two pereopods chelate, first usually much
enlarged. Usually live in mud burrows or in rubble. |
Infraorder
Thalassinidea: Ghost and mud shrimp |
| 56a |
Possess a
distinctive, bulbous, enlarged head
and thorax with two anterior extensions that swing together to form a
false
rostrum. Abdomen narrow and has slender, elongated uropods at the end
(no
tail fan). May or may not have eyes. Burrowing filter feeders |
Order
Cumacea |
| 56b |
Shrimplike,
with a laterally compressed thorax,
and usually have a true rostrum. Most intertidal species have no gills.
Females may have reduced pleopods. Fourth pleopod may be enlarged in
the
male. Possess stalked compound eyes. Freeswimming or benthic. |
Order
Mysida: Opossum shrimps |
| 57a |
Small
(mostly 1-2 mm long), small carapace covers
only first and second thoracic segments. First thoracic appendages are
maxillipeds and second pair are large, subchelate gnathopods. No eyes,
or if eyes are present they are on the ends of immovable stalks. |
Order
Tanaidacea: Tanaidaceans |
| 57b |
Large or
small. With no carapace, though the
head may be fused to one or more thoracic segments. One pair of
maxillipeds
and seven pairs of uniramous pereopods. The coxae of the pereopods
usually
expanded into coxal plates which make the thoracic segments appear to
be
wider or higher than they actually are. Compound eyes sessile, absent,
or on the ends of immovable stalks in one group. |
58 |
| 58a |
The
terga of thoracic segments usually
extend laterally, and the coxal plates of the pereopods often extend
even
farther laterally so that thorax appears wider than it is high
(dorsoventrally
flattened). First pereopod may or may not be subchelate. Well-developed
pleopods, used for gas exchange. Telson is fused with one or more of
the
6 abdominal segments, forming a pleonite. |
Order
Isopoda: Isopods |
| 58b |
The first
one, two, or three pereopods frequently
chelate or subchelate gnathopods. Coxal plates of pereopods usually
extend
ventrally so that thorax appears higher than it is wide (laterally
compressed).
Gills are thoracic. First three abdominal segments have pleopods, last
three have uropods. Telson is free or fused with the last abdominal
segment. |
Order
Amphipoda: Amphipods |
| 59a |
Highly
motile animals, bodies soft and covered
with a mantle; have well-developed eyes and 8-10 arms or tentacles |
Phylum
Mollusca Class Cephalopoda: Octopus, squid |
| 59b |
Do not
have a soft body covered with a mantle,
with both well-developed eyes and 8-10 arms or tentacles |
60 |
| 60a |
Body
composed of a central disk with (usually
5 or more) large projecting rays. Body surface may be hard, membranous,
leathery, or spiny |
61 |
| 60b |
Body not
composed of a central disk with large
projecting rays. |
62 |
| 61a |
Body
surface leathery or spiny, rays thickest
at base and taper gradually into central disk. Underside of rays has a
well-developed ambulacral groove with tube feet. May have up to 25 or
more
rays. Move by attaching and reattaching tube feet. |
Phylum
Echinodermata, Class Asteroidea: Sea Stars |
| 61b |
Body
surface hard or membranous, rays composed
of interlocking ossicles and usually adjoin abruptly to central disk
without
tapering. Usually no more than 5 rays, though they may branch
repeatedly
in basket stars. No ambulacral groove on underside of rays. Move by
lifting
themselves along by the rays. |
Phylum
Echinodermata, Class Ophiuroidea: Brittle Stars |
| 62a |
Body round
or oval, and surrounded by rigid
interlocking plates which form a globular or platelike
“test�.
Covered with large or small movable spines and tube feet. |
Phylum
Echinodermata, Class Echinoidea: Urchins and Sand Dollars |
| 62b |
Body not
composed of a rigid test of interlocking
plates covered with movable spines and tube feet |
63 |
| 63a |
Attached,
colonial, composed of many tiny individuals
(nearly microscopic) each of which is encased in a surrounding calyx,
feeds
with a lophophore, and has a U-shaped gut. Colony may be erect and
bushlike,
leaflike, or a flat crust |
64 |
| 63b |
Not a
colony of nearly microscopic individuals
feeding with a lophophore and with a U-shaped gut |
65 |
| 64a |
Anus is on
an elevated anal cone which is surrounded
by the tentacles of the lophophore (only a few species) |
Phylum
Entoprocta |
| 64b |
Anus open
outside the tentacle ring of the lophophore.
Colonies may be erect, branching, leaflike, or encrusting, and may be
calcified.
Individuals may be boxlike, oval, vaselike, or tubular in shape. Very
common
and abundant fouling organisms |
Phylum Bryozoa
(Ectoprocta): Bryozoans |
| 65a |
Sediment
dwellers. Having an elongated, tapering,
tusk-like shell, open at both ends, one end of which protrudes from the
sediment. |
Phylum
Mollusca, Class Scaphopoda: Tusk Shells |
| 65b |
Having a
single coiled, cap-shaped, earlike,
or irregularly tubelike shell of calcium carbonate |
Phylum
Mollusca, Class Gastropoda: Shelled Snails |