Localization of bioluminescence in the siphonophore Nanomia cara

The base of the tentacle of the developing physonect larva (Nanomia cara) has a bioluminescent region. The ability to produce light in the larva is transitory; this ability first appears at about two days of development and is disappearing by eight days, as the larva begins to feed. Subsequently paired bilaterally symmetrical bioluminescent organs are found on the nectophores and the bracts of the adult colony. In both the larva and the adult, bioluminescence is mediated by a calcium specific photoprotein. In all cases the photocytes lack a green fluorescent protein.