Table 1.
Summary of the ecological characteristics of some large forest former hydrozoans (A, Anthomedusae; L Leptomedusae)
| Order | Species | Geographic distribution | Vertical zonation | Substrate | Shape and skeleton | Reproduction | Associated organisms | Threats |
|---|---|---|---|---|---|---|---|---|
| A | Millepora spp. | Circumtropical | From reef crest | Hard | Larger colonies branched; calcified skeleton | Eumedusoids | Zooxanthellae, Wanella elongatum (Hiro, 1931) (barnacle), Hermodice carunculata (Pallas, 1766) (polychaete, predator), several species of crustaceans, echinoderms, mollusks, nemerteans, polychaetes, and sipunculids | Global warming, bomb fishing, pollution |
| A | Solanderia spp. | Tropical and subtropical | Fore reef | Hard | Fan-shaped to bushy; perisarc stiff | Cryptomedusoids or eumedusoids | Medioantenna spp., serpulids (polychaetes), Licnophora spp. (protozoans), Jason mirabilis M.C. Miller, 1974 and Pleurolidia juliae Burn, 1966 (nudibranches, predators), bivalves, gastropods, tunicates, ophiuroids, copepods, barnacles, amphipods, bryozoans | |
| A | Pseudosolanderia spp. | Circumtropical | Fore reef | Hard | Fan-shaped to bushy; chitinous or from partly to quite totally calcified | Eumedusoids | Lagisca zibrowii Hartmann-Schröder, 1992 (polynoid polychaete), Pachyprocerastea hydrozoicola (Hartmann-Schröder, 1992) and Procerastea simpliseta Hartmann-Schröder, 1990 (syllid polychaetes) | |
| A | Stylasterids | Temperate | Deep waters | Hard | Branched colonies; calcified skeleton | Fixed gonophores in ampullae | Algae, other hydrozoans, scleractinians, Epizoanthus sp. (zoanthid), sponges, bryozoans, commensal polychaetes, Pachylasma giganteum (Philippi, 1836) (barnacle), Pedicularia spp. (gastropods) | Destructive fishing techniques |
| L | Amphisbetia operculata (Linnaeus, 1758) | Temperate and subtropical | From shallow waters in cold regions | Hard substrates on soft bottoms | Bushy with pinnate cormoids; perisarc flexible | Cryptomedusoids | Diatoms, macroalgae, ciliates, other hydrozoans, entoprocta, Doto eireana Lemche, 1976 (nudibranch, predator), other mollusks, bryozoans, tunicates | |
| L | Sertularella diaphana (Allman, 1885) | Tropical and subtropical | Fore reef | Hard | Fan-shaped to bushy; perisarc stiff | Cryptomedusoids | Bivalves, amphipods | |
| L | Sertularia argentea Linnaeus, 1758 | Temperate | From shallow waters in cold regions | Hard | Spiralate colonies; pinnate branches; flexible perisarc | Heteromedusoids | Ornamental harvesting | |
| L | Hydrallmania falcata (Linnaeus, 1758) | Temperate | From shallow to mesophotic zone | Hard substrates on soft bottoms | Pinnate cormoids spirally arranged; perisarc flexible | Fixed gonophores | Other hydroids | Ornamental harvesting |
| L | Aglaophenia cupressina Lamouroux, 1816 | Indo-Pacific | Between reef crest and fore reef | Hard | Bushy with pinnate cormoids; perisarc very flexible | Fixed gonophores protected by corbulae | Zooxanthellae, Cuthona diversicolor Baba, 1975 (nudibranch, predator), cyclopoid copepods, Hyastenus bispinosus Buitendijk, 1939 (crab), fish | Global warming |
| L | Lytocarpia myriophyllum (Linnaeus, 1758). | From boreal to subtropical regions | Mesophotic and deep waters | Soft | Bushy with pinnate cormoids; perisarc very flexible | Fixed gonophores |
Forams, other hydroids, Amphianthus dohrnii (Koch, 1878) (actinian), Dondice banyulensis Portmann & Sandmeier, 1960 (nudibranch, predator, egg deposition), bivalves, stalked barnacles, solenogaster, gastropods, caprellids and gammarids, bryozoans |
Destructive fishing techniques |
| L | Macrorhynchia spp. | Tropical and subtropical | Fore reef | Hard | Fan-shaped, pinnate cormoids; moderately flexible | Fixed gonophores or medusoids, protected by phylactocarps | Other hydroids (Hebellidae), decapod palaemonids | |
| L | Streptocaulus dollfusi (Billard, 1924) | Eastern Atlantic, Strait of Gibraltar | Mesophotic and deep waters | Hard | Erect and polysiphonic colonies, pinnate cormoids | Fixed gonophores protected by phylactocarps | ||
| L | Plumularia elongata (Billard, 1913) | Indo-Pacific | Fore reef | Hard | Fan-shaped to bushy; with pinnate cormoids; strongly polysiphonic and stiff | Fixed or swimming gonophores | Hydrozoanthus gracilis (Lwowsky, 1913) and Hydrozoanthus sp.1 (zoanthids), pycnogonids | |
| L | Pseudoplumaria spp. | Temperate and subtropical | From shallow to deep waters | Soft | With pinnate cormoids | Fixed gonophores | ||
| L | Nemertesia spp. | Cosmopolitan | Mesophotic and deep waters | Hard substrates on soft bottoms | Bushy due to very close unbranched cormoids | Fixed gonophores | Sponges, other hydroids, Alcyonium digitatum Linnaeus, 1758 (anthozoan), nemerteans, bivalves, gastropods (prosobranchs and opistobranchs), Ophiothrix fragilis (Abildgaard, in O.F. Müller, 1789) (ophiuroid), Antedon bifida (Pennant, 1777) (comatulid), polychaetes, gammarid and caprellid amphipods, copepods, cirripeds, cumaceans, isopods, decapods, pycnogonids, entoprocts, bryozoans, tunicates | Destructive fishing techniques |
| L | Polyplumaria flabellata G.O. Sars, 1874 | Temperate and subtropical | Deep waters | Hard | Fan-shaped; with pinnate cormoids; stiff perisarc | Fixed gonophores | ||
| L | Halecium spp. | Boreal and temperate | Mesophotic and deep waters | Hard | Fan-shaped to bushy, pinnate cormoids | Fixed gonophores | ||
| L | Hartlaubella gelatinosa (Pallas, 1766) | Temperate | Deep waters | Mixed substrates | Bushy | Fixed gonophores | Amphipods and caprellids |