Photophore

A photophore is a specialized anatomical structure found in a variety of organisms that emits light through the process of boluminescence. This light may be produced endogenously by the organism itself (symbiotic) or generated through a mutualistic relationship with bioluminescent bacteria (non-symbiotic), resulting in light production on a glandular organ of animals. Light organs are most commonly found in marine animals, including many species of fish and cephalopods. The organ can be simple, or as complex as the human eye, equipped with lenses, shutters, color filters, and reflectors; unlike an eye, however, it is optimized to produce light, not absorb it.

In the context of developmental biology, light organs form through precise genetic regulation and, in some cases, microbial colonization during specific stages of an organism's life cycle. They play a crucial evolutionary role in enabling species to adapt to low-light or dark environments, particularly in the deep sea.