Solvin Zankl / Hatchetfish (Maurolicus walvisensis) close up of photophores beneath its body, emitting bioluminescent light. This glow, directed downward through light-guides, likely serves as counterillumination vi...

Solvin Zankl / Hatchetfish (Maurolicus walvisensis) ventral view portrait, showing photophores beneath its body, emitting bioluminescent light. This glow, directed downward through light-guides, likely serves as cou...

Solvin Zankl / Deep-sea hatchetfish (Maurolicus walvisensis) portrait, showing bioluminescent organs along the underside of its body. These fish inhabit the mesopelagic zone of the open sea, typically at depths of 1...