Portuguese Man-of-War (Physalia physalis)         Bermuda
Photo by Tori Lindo
  Expand Photo

Negative photo image to show tentacles below water.

Man of War scientific classification:

Kingdom: Animalia
Phylum: Cnidaria
Class: Hydrozoa
Order: Siphonophorae
Family: Physaliidae
Genus: Physalia
Species: Physalia physalis

What the heck is a siphonophore?

Biologist and scientists like to have a catalogue or a reference database of scientific and common names of animal species of all life known as the Integrated Taxonomic Information System. The outline or rank of this system is stated as: Kingdom, Phylum, Class, Order, Family, Genus and Species. [1] [2]

Is the man-of-war a jellyfish?

All jellyfish are “jellies,” but not all jellies are jellyfish. Jellyfish or “true jellies” belong to the phylum Cnidaria. Jellies are any animals that have gelatinous body forms and live in the water

The different morphologies (structure) that represent jellyfish have several different cnidarian classes including the Scyphozoa (the true jellyfish class wtih 200 species), Staurozoa (stalked jellyfish, 50 species), Cubozoa (box jellyfish, 20 species), and Hydrozoa (man-of-war, 1000-1500 species). [2]

The Man-of-War on first observation is different then a jelly based on the floating crest above the water as shown in the photos on the left. The Man-of-War can also deflate the crest and submerged completely underwater. It also uses a propulsion system to move through the water unlike the jelly which performs contracting and relaxing of muscles in the umbrella. The biological side of the man-of-war is made up of a colony of organisms working together which is not present in the jellyfish.

In summary, we can say the man-of-war is related to the jellyfish, but belongs to a different class.

Amazing Beauty Of Jellies

The pacific sea nettle(s) in the photo on the right shows the incredible beauty of this particular species. What is truly amazing beyond the beauty is jellies are mostly made of water (about 95 percent); they do not have bones, brains, teeth, blood or fins.

This jelly belongs to the same phylum as the man-of-war but a different class and order as described in the scientific classification below the photo on the right.

To view more photos of the pacific sea nettle and other jellyfish, visit my jelly gallery.

Pacific Sea Nettle (Chrysaora fuscescens),   Montery BayAquarium
Dec 2009, Photo by Mark Leavitt                     
Visit the Jelly Gallery

Sea Nettle scientific classification:

Kingdom: Animalia
Phylum: Cnidaria
Class: Scyphozoa
Order: Semaeostomeae
Family: Pelagiidae
Genus: Chrysaora
Species: Chrysaora fuscescens



  • Retrieved 02-12-2010, from the Integrated Taxonomic Information System (ITIS)
  • www.wikipedia.org, Wikipedia, the free encyclopedia
  • www.montereybayaquarium.org, Jellies on exhibit, Montery Bay Aquarium, Montery, California


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