BBC: Research suggests that bizarre, tentacled worms which live attached to crayfish in the rivers of Australia are at risk of extinction - because the crayfish themselves are endangered.
It would be an example of coextinction, where one organism dies out because it depends on another doomed species.
Just a few millimetres long, the worms eat even tinier critters in the water or inside the crayfish gill chamber.
Their symbiotic relationship stretches back at least 80 million years.
The new...