Phylum Cnidaria: Subtidal Anemones, Corals, and Kin   

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Cnidarians are radially symmetrical predators with relatively simple body structure.  Most are sessile or move only slowly.  Presence of microscopic stinging cells (nematocysts) aids in their effective capture of prey.  10,000 living species.


Subclass Octocorallia (=Alcyonaria)
  Order Gorgonacea                Order Pennatulacea
Leptogorgia
Stylatula elongata
Virgularia
Leptogorgia chilensis Stylatula
elongata
Virgularia
Subclass Zoantharia (=Hexacoralia)
  Order Actiniaria
Anthopleura aremisia
Anthopleura sola Anthopleura xanthogrammica Urticina lofotensis Urticina piscivora Urticina columbiana Urticina crassicornis Urticina coriacea
Anthopleura artemisia Anthopleura
sola
Anthopleura xanthogrammica
Urticina
lofotensis
Urticina
piscivora
Urticina columbiana Urticina crassicornis Urticina
coriacea
Epiactis prolifera
Metridium farcimen Halcampa
Epiactis
prolifera
Metridium
farcimen
Halcampa decemtentaculata
  Order Scleractinia Order Corallimorpharia
Astrangia lajollaensis
Balanophyllia elegans
Paracyathus stearnsi

Corynactis californica
Astrangia lajollaensis Balanophyllia elegans Paracyathus stearnsi

Corynactis californica
  Order Ceriantharia Order Zoanthidea
Pachycerianthus
Epizoanthus scotinus
Pachycerianthus fimbriatus Epizoanthus scotinus

  







Anthopleura artemisia
Anthopleura artemisia  (Pickering in Dana, 1846)
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Actiniaria, Family Actiniidae

Oral disc to 5 cm diameter; tentacles translucent  fluorescent orange or also pale red, white, orange, black or blue.

Moderately common, attached to rocks or shell buried in sand or shell rubble near bases of rock outcrops, usually with only oral disc and tentacles exposed. 

Geogr. Range: Alaska to southern California
Synonyms:
Similar species: distinguished from other anemones by its microhabitat and tentacle color.

Image: Didemnum (middle rt.), Coleopora gigantea (middle far rt.)

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Anthopleura sola
Anthopleura sola  Pearse & Francis, 2000
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Actiniaria, Family Actiniidae

Oral disc to >15 cm diameter with radiating dark stripes; green to dark blue-green; warts (verrucae) on column in longitudinal rows, tentacles sometimes with flecked markings or with pinkish tips. 

Common. Solitary on rocks within kelp forest. Also very abundant in intertidal.  Possess photosynthetic endosymbiotic zooxanthellae (a dinoflagellate) similar to tropical corals.

Geogr. Range: Oregon to Baja
Synonyms: formerly thought to be a solitary form of the cloning intertidal species Anthopleura elegantissima.
Similar species: Anthopleura xanthogrammica lacks distinct radiating markings on oral disc and its tentacles are more uniform in color.

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Anthopleura xanthogrammica
Anthopleura xanthogrammica  (Brandt, 1835)
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Actiniaria, Family Actiniidae

Oral disc to 20 cm diameter, solid green or with very faint radiating markings; tentacles uniform green.  Warts (verrucae) on column not obviously in longitudinal rows. 

Abundant in wave-exposed intertidal sites, less so subtidally in Monterey but occurs to depths of 30 m. elsewhere. Possess photosynthetic endosymbiotic zooxanthellae (a dinoflagellate) similar to tropical corals.

Geogr. Range: Alaska to Baja
Synonyms: Cribrina xanthogrammica
Similar species: Anthopleura sola is nearly as large but darker green in color with distinct radiating lines on oral disc.


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Urticina lofotensis
Urticina lofotensis  (Danielssen, 1890)
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Actiniaria, Family Actiniidae  

Oral disc to >10 cm diameter, column red with distinctive white wart-like verrucae; oral disc red to striped red & tan; tentacles uniform pale red without distinct banding or contrasting markings.  

Common on rocks throughout kelp forest.

Geogr. Range: Alaska to southern California
Synonyms: Tealia lofotensis
Similar species: no other Urticina possess white verrucae on column; U. piscivora has a uniform red column, U. columbiana lives in sand, column of U. crassicornis is mottled green and red, U. coriacea has shorter blunt tentacles banded with red and white.

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Urticina piscivora Urticina piscivora  (Sebens & Laakso, 1978)
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Actiniaria, Family Actiniidae

Oral disc to >15 cm diameter, yellowish with red markings around bases of tentacles; column dark uniform velvet red; tentacles white to pink or red and lack distinct markings.

Abundant; on rocks throughout kelp forest. 

Geogr. Range: Alaska to San Diego
Synonyms: Tealia piscivora
Similar species: U. lofotensis has white verrucae on column, U. columbiana lives in sand, column of U. crassicornis is mottled green and red rather than solid red, U. coriacea has shorter blunt tentacles banded with red and white.

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Urticina columbiana
Urticina columbiana  Verrill, 1922
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Actiniaria, Family Actiniidae  

Oral disc to 20 cm diameter, pale & translucent with radiating markings; column pale red or red-orange with distinctive horizontal rows of ruffled verrucae (warts); tentacles similar to oral disc in color, sometimes with a single dense white longitudinal stripe. 

Infrequent, solitary; partially buried in soft substrate. Typically occurs in deeper water with low wave action in Monterey.

Geogr. Range: British Columbia to Baja
Synonyms: Tealia columbiana
Similar species: U. lofotensis has white circular verrucae on column, U. piscivora has a solid red column, column of U. crassicornis is mottled green and red, U. coriacea has shorter blunt tentacles banded with red and white.

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Urticina crassicornis
Urticina crassicornis  (Muller, 1776)
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Actiniaria, Family Actiniidae  

Oral disc to 15 cm diameter, reddish with radiating markings; column red mottled with green or brownish-green. 

Moderately common, on rocks throughout kelp forest. In Monterey region, more common in Carmel Bay than southern Monterey Bay.

Geogr. Range: Alaska to southern California
Synonyms: Tealia crassicornis
Similar species: U. lofotensis has white verrucae on column, U. columbiana lives in sand, column of U. piscivora is solid red rather than mottled red & green, U. coriacea has shorter blunt tentacles banded with red and white.

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Urticina coriacea Urticina coriacea  (Cuvier, 1798)
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Actiniaria, Family Actiniidae  

Oral disc to 15 cm diameter; tentacles short and blunt with alternating red and white bands; column dark uniform red with densely packed verrucae (warts), sometimes covered with shell debris. 

Infrequent; sometimes attached to rock or shell buried in sand or shell rubble. 

Geogr. Range: Alaska to southern California
Synonyms: Tealia coriacea 
Similar species: U. lofotensis has white verrucae on column, U. piscivora also has a solid red column but its tentacles are longer and tapered, column of  U. crassicornis is mottled green and red, U. columbiana lives in sand. 

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Epiactis prolifera
Epiactis prolifera  Verrill, 1869
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Actiniaria, Family Actiniidae  

Oral disc 2.5 cm in diameter; brown, greenish, or dull red with fine longitudinal lines on lower column & radiating markings on oral disc; usually with brooded young of different sizes attached to base of column. 

Common to abundant but patchy; on rocks & large algae such as Cystoseira. Sequential hermaphrodites (mature first as females & grow into simultaneous hermaphrodites at larger size).

Geogr. Range: Alaska to southern California
Synonyms:
Similar species: no other anemone in Monterey broods young externally; young Anthopleura sola are greener, lack fine lines on column and do not brood young around base.

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Metridium farcimen
Metridium farcimen  (Brandt 1835)
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Actiniaria, Family Metridiidae  

Large to 50 cm tall with lobed oral disc fringed with short fine tentacles; usually white but may be pinkish or tan-brown. 

Abundant in deeper sites that usually lack kelp, especially where water motion is low (e.g. Deep Reef); occasionally found solitarily within kelp forest. 

Geogr. Range: Alaska to southern California
Synonyms: Metridium giganteum
Similar species: Metridium senile is much smaller and grows in clonal clusters in protected sites such as wharf pilings.

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Halcampa decemtentaculata Halcampa decemtentaculata  Hand, 1955
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Actiniaria, Family Halcampidae  

Oral disc 6 mm diameter, column 6 cm tall; 10 white tentacles with dark markings. 

Moderately common but inconspicuous. All but tentacles & oral disc usually buried in shelly gravel or sand.

Geogr. Range: Puget Sound to central California
Synonyms:
Similar species: 

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Corynactis californica
Corynactis californica  Carlgren, 1936
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Corallimorpharia, Family Corallimorphidae

Oral disc 1 cm diameter surrounded by distinctive white club-tipped tentacles.  Column & oral disc uniform in color ranging from red to orange, pink, lavender, or buff.   Form extensive clones that can be distinguished by color.

Very abundant, especially on vertical rock faces throughout kelp forest. 

Geogr. Range: Northern California to Baja
Synonyms:
Similar species: cup corals Balanophyllia elegans and Paracyathus stearnsi have CaCO3 skeletons and their tentacles taper to a point rather than a rounded club.

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Astrangia lajollaensis
Astrangia lajollaensis  Durham, 1946
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Scleractinia, Family Rhizangiidae

Colonial cup coral <5 mm diameter, drab brown-orange with transparent tentacles.  Colonies form by asexual fission but individuals' skeletons do not remain attached to one another.  Swimming planula larvae produced by sexual reproduction (colonies dioecious, either male or female).  

Abundant, especially on vertical rock faces, forming extensive 2-dimensional colonies. 

Geogr. Range: Monterey to Baja
Synonyms:
Similar species: Balanophyllia elegans & Paracyathus stearnsi are solitary & do not form colonies.  Balanophyllia is bright orange rather than brown; Paracyathus is larger, its oral disc tends to be oval rather than round.

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Balanophyllia elegans
Balanophyllia elegans  Verrill, 1864
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Scleractinia, Family Dendrophylliidae

Solitary cup corals <1 cm diameter; bright orange with transparent tapered tentacles.  Produces large (1 mm) non-swimming planula larvae same color as adult.

Ubiquitous; on rocks nearly everywhere in Monterey region, from low intertidal throughout kelp forest & deeper. 

Geogr. Range: Oregon to southern California
Synonyms:
Similar species: Paracyathus stearnsi is brown not orange, larger, taller, tapers from oral disc to base of column & is more oval rather than round. Corynactis californica lacks CaCO3 skeleton, forms clonal colonies and has distinctive club-tipped tentacles.

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Paracyathus stearnsi
Paracyathus stearnsi  Verrill, 1869
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Scleractinia, Family Caryophyliidae

Solitary cup coral 1-2 cm diameter; brown with transparent tentacles.  Corallite expands in diameter upward from base giving it a pedestal shape.  Oral disc often oval rather than round.  Releases planktonic planula larvae.

Abundant, especially on sloped or vertical rock faces; one of the dominant sessile invertebrates at deeper sites with low water motion. 

Geogr. Range: British Columbia to Baja
Synonyms:
Similar species: Balanophyllia elegans is bright orange rather than brown, smaller & round in outline rather than oval. Corynactis californica lacks CaCO3 skeleton, forms clonal colonies and has distinctive club-tipped tentacles.

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Pachycerianthus fimbriatus
Pachycerianthus fimbriatus  McMurrich, 1910
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Ceriantharia, Family Cerianthidae

Tube anemone, tentacles white (infrequently fluorescent orange or dark purple); mucous tube made from specialized nematocysts. 

Abundant, in sandy areas adjacent to rock outcrops; often surrounded by tube worm Diopatra ornata. Nudibranch Dendronotus iris preys on tentacles and lays egg masses on tubes of Pachycerianthus

Geogr. Range: Alaska to Baja
Synonyms:
Similar species: no other tube anemones occur in this microhabitat.

Image: Praxillura (lower rt. of cntr.)

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Epizoanthus scotinus
Epizoanthus scotinus  Wood, 1958
Phylum Cnidaria, Class Anthozoa, Subcl. Zoantharia, Order Zoanthidea, Family Epizoanthidae

Colonial anemone <1 cm diameter; tentacles in single ring around margin of oral disc.  Tan to yellowish-brown. 

Patchy, on vertical rock faces and overhangs. 

Geogr. Range: SE Alaska to southern California
Synonyms:
Similar species: Corynactis californica also forms clones but has white club-tipped tentacles (and is much more common).

Image: Antho lithophoenix (cntr), Clathria pseudonapya? (across top)

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Leptogorgia chilensis
Leptogorgia chilensis  (Verrill, 1868)
Phylum Cnidaria, Class Anthozoa, Subcl. Octocorallia, Order Alcyonacea, Suborder Holaxonia, Family Gorgoniidae

Red gorgonian with white polyps to 90 cm tall; unlike many other sea fans, branches of colony are not in one plane. 

Infrequent in Monterey, on rocks in deep water (usually >30 m in Monterey). 

Geogr. Range: Monterey Bay to Baja
Synonyms:
Similar species: only gorgonian to occur in diving depths in Monterey.



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Stylatula elongata
Stylatula elongata  (Gabb, 1862)
Phylum Cnidaria, Class Anthozoa, Subcl. Octocorallia, Order Pennatulacea, Family Virgulariidae

Sea pen to 40 cm tall (60 cm total length) with bulbous base buried in sand or mud; pale, flesh-colored; tiny polyps with 8 pinnate tentacles arrayed in lateral leaf-like fans supported by spindle-like spines; texture of colony rough, brittle. 

Abundant in sandy areas. Usually at deeper depths in Monterey. Colony can withdraw quickly and completely down into the sand.

Geogr. Range: Marin County to San Diego
Synonyms:
Similar species: Virgularia spp. lacks fans of spindle-like spines supporting lateral branches (difficult to see in the field).



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Virgularia
Virgularia spp.
Phylum Cnidaria, Class Anthozoa, Subcl. Octocorallia, Order Pennatulacea, Family Virgulariidae

Sea pen to 30 cm tall (40-50 cm total length); pale flesh-colored; tiny polyps with 8 pinnate tentacles; lateral leaf-like branches lack supporting fans of spindle-shaped spines; texture of colony smooth, delicate. 

Abundant in sandy areas, usually at deeper depths in Monterey.  Entire colony can withdraw quickly and completely into sand. 

Geogr. Range: Monterey to southern California
Synonyms:
Similar species: Stylatula elongata possesses fan-shaped clusters of spines supporting lateral leaf-like branches (cannot be seen with the naked eye).

Image: Amphiura arcystata (in sand)

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Page created by J.M. Watanabe
All images copyright James Watanabe unless otherwise indicated
Contact:  watanabe_at_stanford_dot_edu                                                                                                                                   Last  update: 21 September 2010