Parasites are really, really important, but often don't make much impact in the public imagination, or if they do make an impact it's negative. They're important for two reasons. Firstly, it's critical to understand the ecology of parasites - they often control their host numbers, and conversely can cause serious problems when introduced into new areas or new hosts.
Secondly, the evolution of parasites is fascinating. Many parasites do remarkable things to survive and prosper in a difficult environment - a host that usually doesn't want to be parasitised and will fight back. And there's an evolutionarily interesting grey area between parasites, commensals (organisms that live on or with a host without negative consequences) and symbionts (two organisms that live together for mutual benefit).
A paper from Jianmei An from Shanxi Normal University in China and colleagues published in Zootaxa, describing a new isopod crustacean parasitising coral crabs from Australia, the Maldives, Japan and Papua New Guinea, is a welcome addition to our knowledge.