Description
Siphonophorae (from Greek siphōn 'tube' + pherein 'to bear') is an order within Hydrozoa, which is a class of marine organisms within the phylum Cnidaria. According to the World Register of Marine Species, the order contains 175 species thus far.
Siphonophores are highly polymorphic and complex organisms. Although they may appear to be individual organisms, each specimen is in fact a colonial organism composed of medusoid and polypoid zooids that are morphologically and functionally specialized. Zooids are multicellular units that develop from a single fertilized egg and combine to create functional colonies able to reproduce, digest, float, maintain body positioning, and use jet propulsion to move. Most colonies are long, thin, transparent floaters living in the pelagic zone.
Like other hydrozoans, some siphonophores emit light to attract and attack prey. While many sea animals produce blue and green bioluminescence, a siphonophore in the genus Erenna was only the second life form found to produce a red light (the first one being the scaleless dragonfish Chirostomias pliopterus ).
