The Darth Vader Isopod Was Discovered in a Seafood Market

In January 2025, scientists described a new giant isopod from the South China Sea and named it Bathynomus vaderi, after Darth Vader. The surprise was where it turned up: not on a deep-sea expedition, but among sea creatures sold alive in Vietnamese seafood shops and restaurants. The holotype, a male bought near Quy Nhơn in March 2022, measures 266 millimetres, more than 10 inches.

Giant isopods are crustaceans, distant cousins of the woodlice and pill bugs that hide under garden stones. The genus Bathynomus lives on the dark sea floor and includes the largest isopods on Earth. According to the ZooKeys paper by Peter Ng, Conni Sidabalok and Nguyen Thanh Son, it already counted 11 supergiant and nine giant living species before this one was added.

Over the previous seven years, the authors write, Bathynomus had become a fashionable delicacy in Vietnam, its meat compared to lobster. Locals call the animals sea bugs. Fishermen began bringing them in from deep water, and shops keep them alive in chilled boxes or cold-water tanks until a diner picks one.

That trade gave the team a large series of animals to study, bought from fishermen and restaurants in Quy Nhơn, Đà Nẵng and Hanoi. Most turned out to be Bathynomus jamesi, a species described in 2017. Six did not fit. Their clypeal region, a plate on the front of the head, was wider and rectangular, and the tail shield carried 11 upturned spines with a distinct row of bristles between them. Those six became the type series of the new species, from 257 to 325 millimetres long.

The name comes straight from the face. The paper says the species honours the most famous Sith Lord in Star Wars because Darth Vader's helmet resembles its head. Seen from the front, the broad, flat shield over the mouthparts really does recall the mask, which is why New Scientist and CNN both led with the Vader link when the species was announced.

Nobody knows exactly where the animal lives. Dealers would only say the catch came from deep water off Vietnam near the Spratly Islands, and the holotype was taken about 50 nautical miles offshore at a depth that was never recorded. A new species reached science through the food chain, before anyone had seen it alive on the sea floor.

Popularity changed the market too. The paper cites Vietnamese press reports of prices up to 2 million dong, about 80 US dollars, per kilogram in 2017, falling to about 1 million dong, around 40 dollars, by early 2024 as more fishermen joined in. The relative B. jamesi can top 2.5 kilograms, and the two biggest males the team examined measured 415 and 410 millimetres. The Straits Times reported the scientists' worry that such demand could lead to overfishing.

The story had a sequel. In 2025 another team described Bathynomus paracelensis from four females caught near the Paracel Islands. A follow-up study in ZooKeys in March 2026 compared the type specimens of both, found no valid differences and nearly identical COI and 16S mitochondrial DNA, and ruled that they are one species. Under the rules of zoological naming the older name wins, so the sea bug keeps its Sith Lord title.

Sources: ZooKeys (2025); ZooKeys (2026); New Scientist; CNN; The Straits Times. Cover: Giant isopod Bathynomus giganteus photographed by NOAA, public domain.