Vampire crabs are a rare species of crustacean that, until recently, had scientists completely stumped - because despite noticing them in pet stores and aquariums around the world, biologists had no idea where they came from. Crab dealers had pointed to a number of possible places of origin, from Borneo to New Guinea, but nothing seemed to quite fit the bill - until finally, with a good deal of detective work, a German carcinologist (crab expert) named Christian Lukhaup was able to trace their origins back to the Indonesian island of Java.

(Source)