Siphonophore

A siphonophore is a colonial marine animal in the order Siphonophorae, within the cnidarian class Hydrozoa.

A siphonophore is a colonial marine animal in the order Siphonophorae, within the cnidarian class Hydrozoa. What appears to be one organism is actually a colony of genetically identical zooids that perform different functions such as feeding, swimming, defence, and reproduction. Many species live in the open ocean, and some are bioluminescent.

Biology

Siphonophores are colonial hydrozoans whose zooids are genetically identical but highly specialized. The colony functions as a single organism even though its parts cannot usually survive independently.

Diversity and classification

The group is placed in the phylum Cnidaria and the class Hydrozoa. Sources give different counts for described species, but generally place the number at roughly 175 to 200.

Habitat and ecology

Most siphonophores are marine and many are pelagic, living in the open ocean. They are carnivorous and use tentacles to capture small prey; some deep-sea species are bioluminescent.

Examples

The Portuguese man-of-war is the best-known example and is often mistaken for a jellyfish. Other siphonophores include long, rope-like deep-sea species that are difficult to collect intact.