Cnidaria · cnidarians
By-the-wind sailor
Velella velella
Porpitidae · blue buttons & sailorsIUCN: Not evaluated
A small blue hydrozoan with a stiff sail that catches the wind.
Fun factIts sail is angled either left or right, so populations drift in different directions.
- Waters
- Worldwide
- Depth zone
- Open-ocean surface waters
- Diet
- Plankton
- Size
- Float up to 7 cm
Classification
Cnidaria › Hydrozoa › Anthoathecata › Porpitidae
- 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 Porpitidae blue buttons & sailors
- Floating disc-shaped hydrozoans with a gas-filled float
- Live at the sea surface, carried by wind
- Genus Velella
- Species in the same genus are very close relatives and often look alike.
- Species Velella velella By-the-wind sailor
Closest relatives in the guide
- Immortal jellyfish Turritopsis dohrnii same order
- Giant siphonophore Praya dubia same class
- Portuguese man o' war Physalia physalis same class