UCSC KFE Fall 2026

65+ Invertebrates

Phylum Porifera: sponges

• Most primitive multicellular inverts
• Sessile suspension feeders
• Provide habitat for other organisms
• Often identified by spicules
• May have chemical defenses
• Asexual and sexual reproduction

​

Acarnus erithacus

Red volcano sponge

One of many red sponges, but raised oscula unique

Acanthancora cyanocrypta

Cobalt sponge

Only blue sponge, encrusting

Tethya californiana

Orange puffball sponge

Solitary or in clumps, can be partially overgrown; always gold-orange

Phylum Bryozoa: moss animals

• Sessile suspension feeders
• Lophophore feeds & respires
• Provide habitat for other organisms
• Zooid encased in hard structure made of CaCO₃ or chitin
• Most species very brittle
• Encrusting and foliose forms
• Asexual and sexual reproduction

​

Primavalens insculpta

Fluted bryozoan

Foliose, corn flake-like, golden, fragile

Diaperoforma californica

Southern staghorn bryozoan

Short branches, densely packed, corrugated surface, golden

Phidolopora pacifica Lacy bryozoan

Foliose, lattice pattern, fragile, orange

Membranipora villosa

Kelp bryozoan

Encrusting, white, on kelp blades

Phylum Cnidaria: anemones, hydroids, corals, & jellies

• Primitive multicellular inverts
• Sessile/sedentary suspension feeders
• Nematocysts are stinging cells
• Toxin is injected via nematocyst
• Asexual and sexual reproduction
• Benthic polyp, swimming medusae
• Radial symmetry

Paracyathus stearnsii

Brown cup coral

Solitary, brown calyx, diameter of a quarter

Lonhart/SIMoN

MBNMS NOAA

Balanophyllia elegans

Orange cup coral

Solitary, bright orange calyx, diameter of dime or nickel

Lonhart/SIMoN

MBNMS NOAA

SIMILAR SPECIES: Astrangia lajollaensis

Colonial brown cup coral

Colonial, small diameter, gold-brown calyx, numerous & dense

Lonhart/SIMoN

MBNMS NOAA

Corynactis californica Strawberry anemone

Tentacles club-tipped, column red or pink or purple, colonial

Pachycerianthus fimbriatus Tube-dwelling anemone

Sandy habitat, large parchment tube, elongate tentacles that can be white, orange, or deep purple

Lonhart/SIMoN

MBNMS NOAA

Metridium farcimen (used to be Metridium giganteum)

Giant metridium

White or light yellow, white tentacles, often >50 cm

Urticina lofotensis (now Cribrinopsis albopunctata)

White-spotted rose anemone

Column is bright red with vertical white dots, slightly bumpy

Urticina crassicornis (now Urticina grebelnyi)

Painted anemone

Mottled green and red column, smooth

Urticina crassicornis (now Urticina grebelnyi)

Painted anemone

Column is mottled red and green, smooth

Urticina piscivora (now Urticina timuri)

Fish-eating anemone

Column is solid red and smooth

Urticina piscivora

Fish-eating anemone

Solid red column, white or red tentacles

SIMILAR SPECIES: Urticina sp. 1

Stubby rose anemone

If on reef (shallow), then longer tentacles, bumpy pale-pink column

SIMILAR SPECIES: Urticina sp. 1

Stubby rose anemone

Column pink, bumpy column with grey spots, covered with debris

SIMILAR SPECIES: Anthopleura sola

Solitary anemone or Sunburst anemone

Green, radiating lines on the oral disk, often has debris on the column

SIMILAR SPECIES: Anthopleura xanthogrammica

Large green anemone

Green, oral disk lacks dark lines

Stylaster californicus

California hydrocoral

Stony, hard, can be pink or purple

​

Stylaster californicus

California hydrocoral

​

Phylum Chordata,

subphylum Tunicata: tunicates

• Our closest relatives among inverts
• Sessile suspension feeders
• Solitary or colonial
• Zooids embedded in jelly-like tunic when in colonial form
• Asexual & sexual reproduction
• Benthic & free-swimming

Aplidium spp.

Colonial tunicate

Can be smooth or covered with epibionts, usually white

Aplidium spp.

Colonial tunicate

Can be smooth or covered with epibionts, usually white

Clavelina huntsmani Lightbulb tunicate

Colonial, pink ‘filament’ looks like a lightbulb

Cystodytes lobatus

Lobed tunicate

Compound, numerous lumps, white or purple or pink

Didemnum carnulentum

Colonial tunicate

White or yellow, many small incurrent holes around larger excurrent

Styela montereyensis

Stalked tunicate

Solitary, can be smooth or covered with epibionts

Phylum Annelida: segmented worms

• Polychaete worms most common
• Sessile suspension feeders and
• Active both crawling & swimming
• Bristles (chaetae)
• Asexual and sexual reproduction

Pileolaria spp. Calcareous tube worm

Small, curled white tubes with orange tissue

Diopatra ornata Ornate tube worm

Tube of thin parchment, in sand, dense,

tube curved like a cane, often covered with shell debris and algae

Lonhart/SIMoN

MBNMS NOAA

Dodecaceria concharum. Reef-building tube worm

Two forms: under crustose coralline with small tufts OR

white calcareous size of a straw with dark green tentacles

Dodecaceria concharum. Reef-building tube worm

Two forms: under crustose coralline with small tufts OR

white calcareous size of a straw with dark green tentacles

Dodecaceria concharum

Colonial tubeworm, white tube with green-brown tentacles,

tube openings 2 mm diameter

Dodecaceria concharum

Colonial tubeworm, white tube with green-brown tentacles,

tube openings 2 mm diameter

Dodecaceria concharum

Colonial tubeworm, white tube with green-brown tentacles,

tube openings 2 mm diameter

Dodecaceria fewkesi. Reef-building tube worm

Two forms: under crustose coralline with small tufts OR

white calcareous size of a straw with dark green tentacles

Eudistylia polymorpha Feather duster tube worm

Big plume of tentacles, colored white or gold, retract very quickly,

tube is white or cream parchment; lacks bands on radioles.

Almost always in dense clusters; always on reef, usually crevices

Phylum Arthropoda: krill, crustaceans, barnacles

• Largest phylum
• Jointed exoskeleton of chitin
• Must molt to increase in size
• Examples of all feeding modes
• Sexual reproduction
• Benthic & free-swimming

Cryptolithodes sitchensis Umbrella crab

ID is easy due to the large carapace covering all the appendages

Pugettia foliatus

Foliate kelp crab

Large chelipeds, broad wings on carapace

Pugettia foliatus

Foliate kelp crab

Large chelipeds, broad wings on carapace

Pugettia foliatus

Foliate kelp crab

Large chelipeds, broad wings on carapace

Pugettia richii

Spider crab

Red, bumpy carapace, often decorated with algae, anterior spines

Pugettia richii

Spider crab

Red, bumpy carapace, often decorated with algae, anterior spines

Pugettia richii

Spider crab

Red, bumpy carapace, often decorated with algae, anterior spines

SIMILAR SPECIES: Pugettia producta

Northern kelp crab

Golden brown or red, smooth clean carapace, often on kelp

SIMILAR SPECIES: Pugettia producta

Northern kelp crab

Golden brown or red, smooth clean carapace, often on kelp

Cancer spp. Cancer crabs

This is Cancer antennarius--purple spots on ventral surface

Cancer spp. Cancer crabs

Juvenile Cancer antennarius--very hairy when young

Cancer spp. Cancer crabs

Juvenile Cancer gracilis -- Graceful cancer crab

Cancer spp. Cancer crabs

Juvenile Cancer magister– Dungeness crab

Loxorhynchus crispatus

Adult Moss crab

Very camouflaged when young, large when older, can look like other spider crabs

Loxorhynchus crispatus Juvenile Moss crab

Very camouflaged when young, large when older, can look like other spider crabs

SIMILAR SPECIES: Scyra acutifrons Sharp-nose crab

Heavily decorated, large, spade-like rostrum, can be confused with juvenile Loxorhynchus

SIMILAR SPECIES: Scyra acutifrons Sharp-nose crab

Heavily decorated, large, spade-like rostrum, can be confused with juvenile Loxorhynchus

SIMILAR SPECIES: Scyra acutifrons Sharp-nose crab

Heavily decorated, large, spade-like rostrum, can be confused with juvenile Loxorhynchus

Loxorhynchus grandis

Adult Sheep crab

Very large, downward-hooked rostral spines; white bumps

Loxorhynchus grandis

Sheep crab

Very large, downward-hooked rostral spines, bumpy carapace

Idotea spp.

Isopod on giant kelp

Phylum Echinodermata: stars, cucumbers, urchins, sand dollars

• Large phylum
• Pentaradial symmetry
• Endoskeleton of CaCO₃ plates
• Water vascular system & tube feet
• Examples of all feeding modes
• Sexual reproduction
• Benthic & free-swimming

Patiria miniata (formerly Asterina miniata)

Bat star, very abundant at many sites, highly variable in color and pattern. Typically has 5 rays, but can be found with more or less.

SIMILAR SPECIES: Mediaster aequalis

Orange star with five rays, large marginal plates, very flattened. Confused with Patiria miniata.

SIMILAR SPECIES: Mediaster aequalis

Orange star with five rays, large marginal plates, very flattened. Can be mistaken for Patiria miniata

Henricia spp. Blood stars

Long, tapered rays, orange or red, patterned aboral surface looks like a series of overlapping ringlets. Usually 5 rays.

Henricia spp. Blood star

Long, tapered rays, orange or red, patterned aboral surface similar to ringlets. Usually 5 rays. (H. sanguinolenta?)

Henricia spp. Blood star

Long, tapered rays, orange or red, patterned aboral surface similar to ringlets. Usually 5 rays.

Henricia pumila Dwarf brooding star

Short, stubby rays; highly variable in color, usually mottled

Orthasterias koehleri

Northern rainbow star

Mottled red, orange and yellow, large, long thick rays

Pisaster giganteus

Giant-spined star

Spines circled with blue ring, thick rays

Pisaster giganteus

Giant-spined star

Spines circled with blue ring, thick rays

Pisaster giganteus Giant-spined star

Spines (white or purple) circled with blue ring

Pisaster giganteus (tan) and Pisaster ochraceus (purple)

Giant-spined and ochre stars

Pisaster ochraceus

Ochre star

Orange, tan or purple color; five rays, white stubby spines

Pisaster brevispinus

Short-spined star

Large, pale pink in color, often on sand, thick rays

Pycnopodia helianthoides

Sunflower star

Very large, >20 rays, very soft and flexible, purple or orange

Pycnopodia helianthoides

Sunflower star juvenile

Most individuals are 10 cm diameter or smaller

Pycnopodia helianthoides

Sunflower star juvenile in WA, 2024

Most individuals are 10 cm diameter or smaller

Juvenile Dermasterias imbricata

Leather star

Very smooth, five rays, mottled aboral surface

Adult Dermasterias imbricata

Leather star

Very smooth, five rays, mottled aboral surface

Mesocentrotus franciscanus (formerly Strongylocentrotus)

Adult Red urchin

Solid red to black underwater, largest in the region

Adult Mesoocentrotus franciscanus

Red urchin

Strongylocentrotus purpuratus

Adult Purple urchin

Green when young, not as large as adult red urchins

Strongylocentrotus purpuratus

Juvenile Purple urchin

Green when young, not as large as adult red urchins

Juveniles: Red urchin on left, Purple urchin on right

Ophioplocus esmarki

Brittle star with round medial disc, elongate rays, short spines

Apostichopus californicus (formerly Parastichopus)

Spiky cucumber

Papillae are fleshy and flexible, light brown

Apostichopus californicus (formerly Parastichopus)

Spiky cucumber

Papillae are fleshy and flexible, light brown

Apostichopus californicus (formerly Parastichopus)

Spiky cucumber

Papillae are fleshy and flexible, light brown

Apostichopus parvimensis (formerly Parastichopus)

Warty cucumber

Papillae are small, small black marking

Apostichopus parvimensis (formerly Parastichopus)

Warty cucumber

Papillae are small, small black marking

SIMILAR SPECIES: Cucumaria miniata

Embedded cucumber

Orange body and tentacles

SIMILAR SPECIES: Cucumaria miniata

Embedded cucumber

Orange body and tentacles

SIMILAR SPECIES: Cucumaria miniata

Embedded cucumber

Orange body and tentacles

Phylum Mollusca: snails, abalone, slugs, & cephalopods

• Second largest phylum
• Many have a CaCO₃ shell
• Examples of all feeding modes
• Radula is a file-like feeding structure
• Sexual reproduction
• Benthic and free-swimming
• Some produce toxins

Crassadoma gigantea

Giant Pacific rock scallop

One valve attached, highly ribbed, many marginal eyes, up to 12 cm in diameter

Crassadoma gigantea

Giant Pacific rock scallop

One valve attached, highly ribbed, many eyes, up to 12 cm in diameter

Cryptochiton stelleri

Gumboot chiton

Deep red color, to 40 cm

Cryptochiton stelleri

Juvenile Gumboot chiton

Mottled-banded, red/pink color

Tonicella spp.

Lined chiton

Multiple species with lines on plates

Calliostoma annulatum

Jeweled top snail, Purple-ringed top snail

Most colorful snail in kelp forest

Calliostoma ligatum

Blue top snail, Blue-lined top snail

Omnivore, consumes compound tunicates and algae

Calliostoma canaliculatum

Channeled top snail

Pale cream shell, deep grooves, thin shell

Tegula brunnea

Brown turban snail

Black foot with orange highlights; tooth and closed umbilicus

Tegula montereyi

Monterey turban snail

Very conical shell; tooth and open umbilicus

Tegula pulligo

Dusky turban snail

Purple and cream pattern on shell; no tooth and open umbilicus

T. brunnea

T. montereyi

T. pulligo

If present,

red arrow points to the ‘tooth’

and

blue encircles

the umbilicus (a central “hole”).

Tegula brunnea

(Chlorostoma brunnea)

Brown turban snail

+ tooth

- umbilicus

Tegula montereyi

(C. montereyi)

Monterey turban snail

+ tooth

+ umbilicus

Tegula pulligo

(Promartynia pulligo)

Dusky turban snail

- tooth

+ umbilicus

Aperture, the opening

of the shell, usually blocked

by the operculum

Spiral rib along base

of shell, ends in a point

we call a “tooth”

Small opening at the center

axis of shell = umbilicus

2 characters differentiate 3 species

Kelletia kelletii

Adult Kellet’s whelk

Natural shell color white with brown lines, usually covered with green and pink algae, yellow foot with black lines and white spots, large

Kelletia kelletii Juvenile Kellet’s whelk

Natural shell color white with brown lines, usually covered with green and pink algae, yellow foot with black lines and white spots, large

Kelletia kelletii Adult Female Kellet’s whelk

Natural shell color white with brown lines, usually covered with green and pink algae, yellow foot with black lines and white spots, large

Pomaulax gibberosus

Red turban snail

Reddish shell but often overgrown, operculum is smooth and calcareous

Pomaulax gibberosus

Red turban snail

Reddish shell but often overgrown, operculum is smooth and calcareous

Pomaulax gibberosus

Red turban snail

Reddish shell but often overgrown, operculum is smooth and calcareous

Pomaulax gibberosus (on right)

Red turban snail

Reddish shell but often overgrown, operculum is smooth and calcareous

Mitra idae Ida’s Miter

Dark black shell, bullet-shaped, and very white foot and tentacles

Neverita lewisii Lewis’s moon snail

In sandy areas, huge foot that can fit into shell, make egg collars that look like gaskets for a flange pipe

Neverita lewisii Lewis’s moon snail

Egg collars wrap around the foot of the female as she extrudes the case, impregnating it with sand to deter predators

Megathura crenulata

Giant keyhole limpet

Solid black or cream with dark lines

Megathura crenulata

Giant keyhole limpet

Solid black or cream with dark lines

Megathura crenulata

Giant keyhole limpet

Solid black or cream with dark lines

Thylacodes squamigerus (formerly Serpulorbis) Scaled worm snail

A vermetid gastropod with an uncoiled shell, orange-lipped mantle, black body; secretes a mucus net to filter feed

Thylacodes squamigerus (formerly Serpulorbis) Scaled worm snail

Here you can see the “scales” along the CaCO₃ tube it builds, cemented to the reef

Haliotis rufescens Red abalone

Most common abalone in subtidal; the foot, epipodial tentacles and mantle are all black in adults

Haliotis rufescens

Red abalone

In younger individuals epipodial tentacles are grey-black and the mantle is alternating black and grey-white

SIMILAR SPECIES: Haliotis kamtschatkana Pinto abalone

Excurrent opening tentacles (tremata) are bright yellow or

bright lime-green

SIMILAR SPECIES: Haliotis kamtschatkana Pinto abalone

Epipodium “mottled pale yellow to dark brown”, epipodial tentacles yellow-brown, sometimes greenish

SIMILAR SPECIES: Haliotis kamtschatkana Pinto abalone

Margin and mantle are highly stippled, with numerous small bumps

SIMILAR SPECIES: Haliotis walallensis Flat abalone

Epipodial tentacles more typically dark brown to black

SIMILAR SPECIES: Haliotis walallensis Flat abalone

Margin and mantle highly stippled

Neobernaya spadicea

Chestnut cowry

Golden-brown top, very smooth, uncommon in central CA

Neobernaya spadicea

Chestnut cowry

Usually in deeper waters, more common near Point Lobos

California sea hare

Burgundy red with black mottling, up to size of football, called a “hare” due to large “ears”

Lonhart/SIMoN

MBNMS NOAA

Aplysia californica

Lonhart/SIMoN

MBNMS NOAA

SIMILAR SPECIES: Aplysia vaccaria Black sea hare

Lonhart/SIMoN

MBNMS NOAA

Eernisse 2010

Aplysia californica versus Aplysia vaccaria

Noble sea lemon Peltodoris nobilis (formerly Montereina, Anisodoris)

Dorsal papillae rounded, black in between, white plume

Noble sea lemon vs. Monterey dorid

Monterey dorid Doris montereyensis

Yellow plume, dorsal papillae black tipped, pointed

Doriopsilla albopunctata

Numerous small white dots, white plume

Ceratostoma foliatum Leafy hornmouth

Three varices (wings), tooth at aperture, white shell with brown banding if not encrusted with epibionts

Ceratostoma foliatum Juvenile Leafy hornmouth

Three varices (wings), tooth at aperture, white shell with brown banding, old tooth evident between lower brown bands

Ceratostoma foliatum Leafy hornmouth

Red arrow is pointing at the newest tooth

SIMILAR SPECIES: Pteropurpura macroptera

Much smaller as an adult and no tooth. Often in an aggregation.

SIMILAR SPECIES: Pteropurpura macroptera

Eight feeding on barnacles. Brown shell with faint lines.

SIMILAR SPECIES: Pteropurpura macroptera

Similar to Ceratostoma, but much smaller and no tooth. New varex

(i.e. a new “wing”) with no epibiotic overgrowth on it yet.

Ceratostoma foliatum (left) and Pteropurpura macroptera (right)

Tooth on left and no tooth on right.

Lonhart/SIMoN

MBNMS NOAA

Ceratostoma foliatum (left) and Pteropurpura macroptera (right)

Tooth on left and no tooth on right.

Lonhart/SIMoN

MBNMS NOAA