# A bioluminescent deep-sea polychaete within the genus Aricidea (Paraonidae) from Minamidaito Island, Japan

## TL;DR

Scientists discovered a new bioluminescent worm in the deep sea near Japan, which is the first of its kind in this family.

## Contribution

This is the first report of bioluminescence in the Paraonidae family of annelids.

## Key findings

- A new bioluminescent species was identified in the genus Aricidea.
- The worm emits green light when stimulated.
- Molecular analysis suggests it belongs to the Aricidea/Paraonis clade but is not a known species.

## Abstract

The phylum Annelida encompasses a diverse group of animals, with bioluminescent species documented in 14 families. Despite this diversity and the scattered distribution of bioluminescent lineages, little is known about the molecular biology, chemistry, morphology, ecology, and evolution of bioluminescence in annelids. During a deep-sea exploration off Minamidaito Island in the western Pacific Ocean, we discovered that Aricidea sp. emits green light when stimulated. The specimens were identified with the limited key morphology as a species in the genus Aricidea. A molecular phylogenetic analysis suggests that the specimen belongs to the Aricidea/Paraonis clade but was not nested in the described species, of which sequences were publicly available. This study is the first to report bioluminescence within the family Paraonidae.