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 species. Giant isopods of the genus Bathynomus can grow over 11 inches long, with the largest (Bathynomus giganteus) believed to be almost 20 inches long. They are called bọ biển or “sea bugs” in Vietnamese.
In March 2022, a team from Hanoi University purchased four giant isopod individuals from a market in Quy Nhơn City. To identify these large crustaceans, the team in Hanoi collaborated with scientists from the National University of Singapore, the National Research and Innovation Agency Indonesia, and the Vietnam National University. By early 2023, the team realized that these giant isopods belonged to a species that had not been described by scientists.
Bathynomus vaderi is considered a supergiant isopod, reaching about 12.7 inches long and weighing over 2.2 pounds. Like other giant isopods, B. vaderi is a carnivore and is known to eat crab, shrimp, fish, sponges, squid, and munch on whale carcasses. So far, it has only been found near the Spratly Islands in Vietnam by fishers trawling for isopods. The team believes that additional research will confirm its presence in other parts of the South China Sea.
Giant isopods are also considered an expensive delicacy in Vietnam and other parts of Asia. Previously, they had only been sold as a bycatch project at low prices by local fishermen. Since 2017, media attention has put some spotlight on this strange seafood, with some claiming it’s even tastier than lobster. Their popularity has led to them being commercially fished by trawlers operating in various deep-water parts of the East Sea–the Vietnamese part of the South China Sea–and offshore of provinces in southcentral coastal Vietnam. They are often sold alive in markets in major cities and some restaurants will advertise the sale of these so-called “sea bugs.”
[ Related: This giant isopod lives in the crater of a dinosaur-killing asteroid. ]
The discovery of this strange species also highlights just how little we know about the deep-sea. According to the team, a species this large remaining hidden for so long indicates that a lot of work must be done to fully understand what lives in Southeast Asia’s waters. A better understanding can help inform fisheries policies, as the potential for exploration for oil, gas, and minerals in the deep ocean continues to grow.
Win the Holidays with PopSci’s Gift Guides
