Delphirondes

Delphirondes are a fictional genus of deep-sea marine invertebrates described in speculative biology. The name combines delphos, Greek for dolphin, and rhônos, round, a reference to their round, glow-ringed bodies.

Individuals are disc-shaped, 3–7 cm in diameter, with four concentric photophore rings that emit blue-green light. The central core is gelatinous; the rings are composed of light-emitting cells and symbiotic bacteria that contribute to luminescence. When threatened, they can adjust ring brightness and pattern; in motion they appear as rotating halos.

They inhabit mid- to deep-ocean habitats around seamounts and hydrothermal plumes, in the fictional western Pacific and neighboring basins. They are detritivores and filter feeders, feeding on plankton and organic particles carried by currents. They harbor bacterial symbionts within photophore tissues.

Socially, delphirondes form loose aggregations called ronde clusters that drift with currents. Communication is thought to rely on patterned light pulses and faint acoustic signals; reproduction is sexual, with external fertilization in a planktonic larval stage.

In scholarly fiction, Delphirondes have been used as a model for studying bioluminescence, host-symbiont relationships, and the evolution of light-based signaling in marine life. They are frequently cited in world-building guides and speculative biology discussions as an example of light-driven ecological interaction in the deep sea.