One of the rarest sea creatures in the world called Allonautilus scrobiculatus has been spotted for the first time in 30 years off the coast of Papua New Guinea, The Independent reports.

Peter Ward, a biology professor at the University of Washington, first saw Allonautilus scrobiculatus in 1984.

These creatures are thought to have survived two ice ages and dinosaur era. They have been seen by only two people in the world.  

The creatures need a delicate balance to survive: unable to cope in water too hot, they will also perish in case they exceed 2,500m depth.

Currently, the animals are threatened by extinction due to illegal fishing and mining operations.