Poecilostomatoid
Guides
Oncaea
Oncaea is a genus of small marine copepods in the family Oncaeidae, order Poecilostomatoida. The genus includes bioluminescent species that exhibit internal (non-secreted) bioluminescence, a distinctive trait among copepods. Members occur in marine environments from tropical to polar regions, including the Arctic Ocean, Antarctic waters, and the Mediterranean Sea. Some species have been documented feeding on chaetognaths and other crustaceans, though feeding mechanisms appear complex and variable.