Porpita
Porpita is a genus of colonial hydrozoans in the family Porpitidae, commonly known as the blue button or the blue bottle. These organisms are often mistaken for jellyfish but are in fact colonies of polyps, each specialized for a different function.
Common Names
Porpita species are commonly referred to as:
- Blue button
- Blue bottle
- By-the-wind sailor
- Sea blubber
Characteristics
The most recognizable feature of Porpita is its flattened, disk-shaped colony, which can range in size from a few centimeters to several inches in diameter. The colony is made up of numerous polyps, each specialized for a different function, including feeding, reproduction, and defense. The central polyp, known as the gastrozooid, is responsible for digestion and is surrounded by a ring of dactylozooids, which are specialized for capturing prey.
The upper surface of the colony is covered with a gas-filled sac, called the pneumatophore, which allows Porpita to float on the surface of the water. The pneumatophore is typically blue in color, hence the common name "blue button." The underside of the colony is covered with tentacles that contain stinging nematocysts used to paralyze prey. The tentacles are typically much longer than the diameter of the colony and can extend up to several feet in length.
Environment
Porpita species are found in tropical and subtropical waters worldwide. They are often observed in large numbers, particularly during the summer months when water temperatures are warmer. They are typically found in open ocean waters but can occasionally be washed ashore by strong currents or winds.
References
For further information on Porpita, please refer to the following resources: