Fish
Roughskin Dogfish
Centroscymnus owstonii · also called Owston's dogfish
Coated in unusually coarse, sandpaper-like skin and carrying its own built-in lighting system, a roughskin dogfish drifts along the seafloor far below the sun, quietly countering its own shadow to stay hidden from predators patrolling above.
Overview
The roughskin dogfish, Centroscymnus owstonii, is a small deep-sea shark native to deep ocean habitat recorded across scattered locations in the Pacific, Atlantic, and Indian Oceans. Its unusually coarse skin texture, belly-mounted light-producing organs, and life spent entirely beyond the reach of sunlight make it one of many quietly specialised predators patrolling the deep continental slopes.
Hiding in plain sight, several hundred fathoms down
Even in near-total darkness, a stray silhouette against faint surface light can give a predator away, and the roughskin dogfish’s belly full of tiny light-producing organs exists specifically to erase that risk, a strategy shared by many deep-sea sharks that never see true sunlight.
Status
Near Threatened, with populations facing pressure from deep-sea fisheries bycatch and limited by the species’ naturally slow reproduction.
Roughskin Dogfish: common questions
Why is the roughskin dogfish's skin so rough?
This species is covered in unusually coarse, enlarged dermal denticles, giving its skin a distinctly rough, sandpaper-like texture even compared with most other shark species, whose skin is already textured by similar structures.
How does the roughskin dogfish use light in complete darkness?
This species has light-producing photophores concentrated along its belly, used to counter-illuminate its silhouette from below, helping it blend into the faint light filtering down from the surface and avoid being spotted by predators looking upward.
How deep does the roughskin dogfish live?
This species is typically found at great depths on continental slopes, far below where sunlight penetrates, an environment shared by many other deep-sea shark species.
Does the roughskin dogfish lay eggs?
No, this species is ovoviviparous, with young developing inside the mother and being born live rather than hatching from eggs laid externally.