Cnidaria · cnidarians
Immortal jellyfish
Turritopsis dohrnii
Oceaniidae · oceaniid hydroidsIUCN: Not evaluated
A tiny hydrozoan jelly that can revert to its juvenile polyp stage.
Fun factWhen stressed, it turns back into a polyp and starts its life over.
- Waters
- Worldwide, Mediterranean & Black Sea
- Depth zone
- Coastal shallows & estuaries
- Diet
- Plankton
- Size
- About 4.5 mm across
Classification
Cnidaria › Hydrozoa › Anthoathecata › Oceaniidae
- Kingdom Animalia animals
- Many-celled organisms that eat other living things for energy (heterotrophs)
- Cells have no cell walls
- Most can move at some stage of life
- Phylum Cnidaria cnidarians
- Radially symmetric bodies with one opening that is both mouth and anus
- Stinging cells (cnidocytes) fire tiny harpoons (nematocysts)
- Two body forms: an attached polyp and a swimming bell (medusa)
- Class Hydrozoa hydrozoans
- Mostly small, often colonial animals with both polyp and medusa stages
- Medusae have a shelf of tissue (velum) under the bell
- Includes hydroids, fire corals, and siphonophores
- Order Anthoathecata athecate hydroids
- Hydroids whose polyps lack a protective cup (theca)
- Includes by-the-wind sailors and fire corals
- Family Oceaniidae oceaniid hydroids
- Small hydrozoan jellies with a tall bell
- Includes the 'immortal' jellyfish that can turn back into a polyp
- Genus Turritopsis
- Species in the same genus are very close relatives and often look alike.
- Species Turritopsis dohrnii Immortal jellyfish
Closest relatives in the guide
- By-the-wind sailor Velella velella same order
- Giant siphonophore Praya dubia same class
- Portuguese man o' war Physalia physalis same class