Portuguese man-of-war, Physalia physalis
from the Pacific Ocean (Hawaiian Islands)
Photographic portrait by Eric Röttinger
Source: EMBO Winners 2014
The man-of-war is a siphonophore [a class of Cnidarians in the order Hydrozoa where each specimen is actually a colony composed of many individual animals], in this case made up of four types of polyps that form a colony.
- The pneumatophore is a gas-filled filled polyp that floats on the water surface and allows the colony to sail across the oceans.
- The polyps that form the long and venomous tentacles (dactylozoids) are responsible for catching the prey,
- supplying the gastrozoids (polyps in charge of digestion) with food.
- The fourth type of polyps, the gonozoids, are in charge of sexual reproduction.
Eric Röttinger is a developmental biologist and Group-leader at the Institute for Research on Cancer and Aging in Nice (France) and co-founder of the non-profit organization Kahi Kai (‘one ocean’ in native Hawaiian)