There are 302 species of cnidarians (phylum Cnidaria) recorded in Ireland.
The cnidarians' distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey. Their bodies consist of mesoglea, a non-living jelly-like substance, sandwiched between two layers of epithelium that are mostly one cell thick. They have two basic body forms: swimming medusae and sessile polyps, both of which are radially symmetrical with mouths surrounded by tentacles that bear cnidocytes. Both forms have a single orifice and body cavity that are used for digestion and respiration. Many cnidarian species produce colonies that are single organisms composed of medusa-like or polyp-like zooids, or both (hence they are trimorphic).
Cnidarians found in Ireland and Irish waters include sea pens, sea anemones, hydroids, sea jellies ("jellyfish") and corals.
Class Anthozoa
Order Actiniaria (sea anemones)
Family Actiniidae
Actinia equina (beadlet anemone) Actinia fragacea (strawberry anemone) Anemonia viridis (snakelocks anemone) Anthopleura ballii (red speckled anemone) Aulactinia verrucosa (gem anemone) Urticina eques Urticina felina (northern red anemones, dahlia anemone)
Family Actinostolidae
Stomphia coccinea
Family Aiptasiidae
Aiptasia mutabilis
Family Capneidae
Capnea sanguinea
Family Edwardsiidae
Edwardsia claparedii Edwardsia delapiae Edwardsia timida (timid burrowing anemone) Edwardsiella carnea Scolanthus callimorphus
Family Gonactiniidae
Gonactinia prolifera
Family Halcampidae
Halcampa chrysanthellum
Family Halcampoididae
Halcampoides elongatus
Family Haloclavidae
Mesacmaea mitchellii Peachia cylindrica
Family Hormathiidae
Adamsia carciniopados Adamsia palliata (cloak anemone) Calliactis parasitica Cataphellia brodricii Hormathia coronata
Family Metridiidae
Metridium senile (plumose anemone, frilled anemone)
Family Sagartiidae
Actinothoe sphyrodeta Cereus pedunculatus (daisy anemone) Phellia gausapata Sagartia elegans Sagartia ornata Sagartia troglodytes (mud sagartia, cave-dwelling anemone) Sagartiogeton laceratus Sagartiogeton undatus
Order Alcyonacea (soft corals)
Family Alcyoniidae
Alcyonium digitatum (dead man's fingers) Alcyonium glomeratum (red sea fingers) Alcyonium hibernicum (pink sea fingers) Parerythropodium coralloides
Family Gorgoniidae
Eunicella verrucosa (broad sea fan, pink sea fan, warty gorgonian)
Family Plexauridae
Swiftia pallida (northern sea fan)
Order Ceriantharia (tube-dwelling anemone)
Family Arachnactidae
Arachnanthus sarsi
Family Cerianthidae
Cerianthus lloydii (lesser cylinder anemone) Pachycerianthus multiplicatus (firework anemone)
Order Corallimorpharia
Family Corallimorphidae
Corynactis viridis
Order Pennatulacea (sea pens)
Family Virgulariidae
Virgularia mirabilis
Order Zoantharia
Family Epizoanthidae
Epizoanthus couchii
Family Parazoanthidae
Isozoanthus sulcatus Parazoanthus anguicomus Parazoanthus axinellae (yellow cluster anemone)
Class Hydrozoa
Order Anthoathecata (athecate hydroids)
Family Bougainvilliidae
Bougainvillia muscus Garveia nutans
Family Candelabridae
Candelabrum phrygium
Family Corymorphidae
Corymorpha nutans
Family Corynidae
Coryne eximia Coryne muscoides Sarsia densa
Family Eudendriidae
Eudendrium annulatum Eudendrium arbuscula Eudendrium ramosum
Family Hydractiniidae
Clava multicornis Hydractinia echinata (snail fur)
Family Hydridae (hydras)
Hydra viridissima (green hydra) Hydra vulgaris (common hydra)
Family Pandeiidae
Leuckartiara octona Neoturris pileata
Family Porpitidae (chondrophores)
Velella velella (sea raft, by-the-wind sailor, purple sail, little sail)
Family Tubulariidae
Ectopleura larynx Tubularia indivisa (oaten pipes hydroid)
Order Leptomedusae (thecate hydroids)
Family Aequoreidae
Aequorea forskalea Aequorea vitrina
Family Aglaopheniidae
Aglaophenia acacia Aglaophenia kirchenpaueri Aglaophenia pluma (toothed feather hydroid, podded hydroid) Aglaophenia tubiformis Aglaophenia tubulifera Gymnangium montagui Lytocarpia myriophyllum
Family Campanulariidae
Campanularia hincksii Clytia hemisphaerica Laomedea angulata Laomedea flexuosa Obelia dichotoma Obelia geniculata Obelia longissima Obelia plicata Rhizocaulus verticillatus
Family Haleciidae
Halecium beanii Halecium halecinum Halecium muricatum Halecium plumosum
Family Halopterididae
Antennella secundaria Halopteris catharina Schizotricha frutescens
Family Kirchenpaueriidae
Kirchenpaueria pinnata
Family Lafoeidae
Lafoea dumosa
Family Plumulariidae
Nemertesia antennina Nemertesia ramosa Plumularia argentea Plumularia cupressina Plumularia distans Plumularia setacea (plumed hydroid, little sea bristle) Polyplumaria flabellata
Family Sertulariidae
Abietinaria abietina Abietinaria filicula Amphisbetia operculata Diphasia alata Diphasia attenuata Diphasia fallax Diphasia nigra Diphasia pinaster Diphasia rosacea Dynamena pumila Hydrallmania falcata Sertularella fusiformis Sertularella gayi Sertularella mediterranea Sertularella polyzonias Sertularella rugosa Tamarisca tamarisca Thuiaria articulata (jointed hydroid) Thuiaria thuja
Order Limnomedusae
Family Olindiidae
Craspedacusta sowerbii
Order Siphonophorae (siphonophores)
Family Apolemiidae
Apolemia uvaria (string jellyfish, barbed wire jellyfish, long stringy stingy thingy)
Family Physaliidae
Physalia physalis (Portuguese man-o'-war, blue bottle, floating terror)
Class Scyphozoa (true sea jellies)
Order Rhizostomeae
Family Rhizostomatidae
Rhizostoma pulmo (barrel jelly, dustbin-lid jelly, frilly-mouthed jelly)
Order Semaeostomeae (flag-mouth sea jellies)
Family Cyaneidae
Cyanea capillata (lion's mane jelly) Cyanea lamarckii (blue jelly, bluefire)
Family Pelagiidae
Chrysaora hysoscella (compass jelly) Pelagia noctiluca (mauve stinger)
Family Ulmaridae
Aurelia aurita (moon jelly, common jelly, saucer jelly)
Order Scleractinia (stony corals, hard corals)
Family Caryophylliidae
Caryophyllia inornata Caryophyllia smithii (Devonshire cup coral) Lophelia pertusa
Family Oculinidae
Madrepora oculata (zigzag coral)
Class Staurozoa
Order Stauromedusae (stalked jellies)
Family Craterolophidae
Craterolophus convolvulus
Family Kishinouyeidae
Lucernariopsis campanulata
Family Lucernariidae
Haliclystus auricula (kaleidoscope jelly)
References
World Register of Marine Species
External links Marine species identification portal