HIERARCHICAL CLASSIFICATION OF THE PHYLUM CNIDARIA
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PHYLUM CNIDARIA LINKS
- CLASS HYDROZOA (5 ORDERS)
- Polyp and medusoid stages; either might be reduced. Mesogloea acellular; nematocysts only in epidermis; gametes develop in epidermis. Polyp radially symmetrical. Coelenteron not separated by septa. Typically colonial with individuals connected; often individual polyps with different functions. Medusoid form small, usually with mouth on hollow stalk. Shelf or velum extending inward from the margin of the bell. >3,000 extant species.
- Bouganvilla, Calycopsis, Eleutheria, Eudendrium, Hydra, Hydractina, Hydrocoryne, Janaria, Lar, Pennaria, Polyorchis, Sarsia, Staurocladia, Stylactis,Tubularia, Abietinaria, Aequoria, Aglaophenia, Bonneviella, Campanularia, Cuvieria, Obelia, Gonionemus, Gonothyrea, Lovenella, Plumularia, Sertularia, Aegina, Botrynema, Craspedacusta, Cunina, Hydroctena, Liriope, Polypodium, Rhopalonema, Solmissus, Agalma, Apolemia, Eudoxoides, Nectocarmen, Physalia, Rhyzophysa, Sphaeronectes, Porpita, Velella, Halammohydra, Otohydra.
- Polyp and medusoid stages; either might be reduced. Mesogloea acellular; nematocysts only in epidermis; gametes develop in epidermis. Polyp radially symmetrical. Coelenteron not separated by septa. Typically colonial with individuals connected; often individual polyps with different functions. Medusoid form small, usually with mouth on hollow stalk. Shelf or velum extending inward from the margin of the bell. >3,000 extant species.
- CLASS SCYPHOZOA (4 ORDERS)
- Medusa dominant; polyp small or absent. Medusa large and free living. Gastrodermal gonads. Mesogloea cellular. No velum. Coelenteron partitioned by four septa. ~200 extant species.
- Aurelia, Cyanea, Haliclystus, Lucernaria, Atolla, Linuche, Naustihoe, Periphylla, Stephanoscyphus, Tetraplatia, Chrysaora, Pelagia, Sanderia, Stygiomedusa, Cassiopeia, Cephea, Eupilema, Mastigias, Rhizostoma, Stomolophus.
- Medusa dominant; polyp small or absent. Medusa large and free living. Gastrodermal gonads. Mesogloea cellular. No velum. Coelenteron partitioned by four septa. ~200 extant species.
- CLASS CUBOZOA (1 ORDER)
- Medusa square with four flat sides. Margin of bell drawn in to form velum-like organ. Tentacle (or cluster) at each corner. Nematocysts very painful. ~15 extant species.
- Tripedalia, Carybdea, Chironex, Tamoya.
- Medusa square with four flat sides. Margin of bell drawn in to form velum-like organ. Tentacle (or cluster) at each corner. Nematocysts very painful. ~15 extant species.
- CLASS STAUROZOA
- Attached medusozoan, but no medusoid stage; rectangular symmetry. Capitate tentacles. About 50 species.
- ‘ANTHOZOA’
- No medusoid stage. Polyp large with thick, cellular mesogloea. Coelenteron partitioned by mesentaries with glands, filaments and nematocysts. Stomodaeum extends from mouth down into enteron. One or two ciliated grooves directing water into coelenteron. Oral disc surrounded by tentacles. Epidermal and gastrodermal nematocysts. No operculum. Often colonial. ~6,000 extant species.
- CLASS HEXACORALLIA (=ZOANTHARIA; 5 ORDERS)
- Solitary or colonial anthozoans, most with secreted supporting material that is calcareous and external to the polyp. Polyps with six (or multiples thereof) simple tentacles. Coelenteron divided into many compartments by paired septa, also in multiples of six and with retractor muscles.
- Adamsia, Aiptasia, Alicia, Anthopleura, Anthothoe, Bartholomea, Bunodactis, Calliactus, Condylanthus, Diadumene, Edwardsia, Epiactus, Halcampa, Haliplanella, Heteractis (Radianthus), Liponema, Metridium, Peachia, Phyllodiscus, Ptychodactis, Stichodactyla, Stomphia, Triactis, Agaricia, Astrangia, Balanophyllia, Dendrogyra, Flabellum, Actinia, Fungia, Goniopora, Letepsammia, Meandrina, Montipora, Oculina, Pachyseris, Porites, Psammocora, Siderastraea, Stylophora, Epizoanthus, Isaurus, Isozoanthus, Palythoa, Parazoanthus, Thoracactus, Zoanthus, Amplexidiscus, Corynactis, Rhodactis, Ricordea.
- ORDER CERIANTHARIA is basal in this class. Unspecialized musculature. Mesentaries (single, not paired and complete) and tentacles simple. Six primary mesenteries.
- Cerianthus, Antipathes, Arachnanthus, Botruanthus, Ceriantheomorphe, Ceriantheopsis, Pachycerianthus.
- CLASS OCTOCORALLIA (=ALCYONARIA; 8 ORDERS)
- Colonial with internal skeleton of calcium carbonate or horny material. Polyps with eight tentacles and coelenteron divided into eight compartments by mesenteries.
- Alcyonium, Anthomastus, Ceratocaulon, Gersemia, Parerythropodium, Pseudogorgia, Acanthogorgia, Biareum, Corallium, Eugorgia, Eunicella, Isis, Leptogorgia, Muricea, Parisis, Psamogorgia, Swiftia, Epiphaxum, Heliopora, Anthoptilum, Balticina, Cavernularia, Funicularia, Ptilosarcus, Stylatula, Umbellula, Virgularia, Haimea, Hartea, Monoxenia, Psuchastes, Taiaroa, Clavularia, Cornularia, Sarcodictyon, Tubipora, Gorgonia, Renilla, Pennatula, Coelogorgia, Paratelesto, Telesto, Telestula.
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| By Jack R. Holt and Carlos A. Iudica. Last revised: 01/27/2013 |
