Physalia physalis
From Palaeos
| CNIDARIA | |
| Taxonomy | Phylogeny |
o Radiata (grade) |?--Ctenophora `--+--Cnidaria | |--Anthozoa | `--+--Hydrozoa | `--+--+--Scyphozoa | | `--Cubozoa | `?-Conulata (polyphyletic?) `--Bilateria | |
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Cnidaria topics: | Life Cycle | Coral reefs | References | Links |
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Contents |
Introduction
Physalia physalis, the Portuguese Man O' War, also known as the bluebubble or bluebottle, is commonly thought of as a jellyfish but is actually a siphonophore—a colony of four sorts of polyps.
A similar group of animals are the chondrophores.
Information
Taxonomy:
Author: Linnaeus, 1758
Srtratigraphic range: Recent
Distribution: Cosmopolitan
Structure
The Man Of War's float is bilaterally symmetrical with the tentacles at one end, while the chondrophores are radially symmetrical with the sail at an angle. Also the Man O' War has a siphon, while the chondrophores do not.
The Portuguese Man O' War has an air bladder; known also as a pneumatophore or sail, that allows it to float on the surface of the ocean. It has no means of propulsion and is pushed by the winds and the current. The sail is filled with air, but may build up a high concentration of carbon dioxide (up to 90%). The bladder must stay wet to ensure survival; every so often it may roll slightly to wet the surface of the float. To escape a surface attack, the pneumatophore can be deflated allowing the Man O' War to briefly submerge.
Below the main body dangle long tentacles, sometimes reaching 165 feet (50 meters) in length below the surface, although 30 feet (10 meters) is more the average. They sting and kill small sea creatures using poison-filled nematocysts and use muscles to draw the prey in to the gastrozooids, which are yet another different type of polyp that surround and digest it. Gonozooids are responsible for reproduction.
Ecology
The man-of-war fish, whose name is derived from the Portuguese Man O' War, often lives within the man o' war's tentacles for protection. Like the man o' war, the nudibranch glaucus atlanticus or blue sea slug, uses a gas filled sac to stay afloat and, being immune to its poison, preys on it and other neustons.
Portuguese Man O' War are a very important source of food to sea turtles, which are immune to the poison. Sea slugs and sea snails floating on the water are also immune to the poison. The Portuguese Man O' War can be found on the coast of Africa, North America, Europe and Australia as well as in other areas of the world.
Poison
The sting from the tentacles is potentially dangerous to most humans; these stings have been responsible for several deaths, but usually only cause excruciating pain.
Origin of the name
The Man O' War is named for its air bladder, which looks similar to a man of war under sail, namely a Portuguese Caravel.
