Share A purchase at an urban Vietnamese fish market turned out to be a whole new species of giant isopod–with a bit of a dark side. The foot-long crustacean has been named Bathynomus vaderi and sports a head that resembles the iconic helmet of Darth Vader from the Star Wars. It is the first giant sea bug discovered in Vietnamese waters and is described in a study published January 14 in the journal ZooKeys. Isopods are related to pillbugs seen on land and scientists estimate that there are about 10,000…