The head of Bathynomus vaderi. (Credit: Nguyen Thanh Son)
HANOI, Vietnam — Deep in the waters off Vietnam’s coast, scientists have discovered a new species of giant isopod — a creature that looks like a massively oversized roly-poly or pill bug. Named Bathynomus vaderi after the iconic Star Wars villain, this deep-sea creature earned its moniker from its distinctive head shape, which bears an uncanny resemblance to Darth Vader’s helmet.
Measuring up to 325 millimeters (nearly 13 inches) long, B. vaderi joins an elite group of marine giants. It represents only the fourth known species of its kind to possess distinctively upward-curved spines along its tail section, making it a unique find in the deep waters of the South China Sea.
This discovery came through an unexpected partnership between science and seafood. Since 2017, these giant isopods have become prized delicacies in Vietnam, where they’re known as “bọ biển” or “sea bugs.” High-end restaurants keep them alive in chilled tanks, treating them as prestigious seafood on par with lobster. At their peak in 2017, these creatures commanded prices of up to 2 million Vietnamese Dong (approximately $80) per kilogram, though prices have since decreased to around $27-40 per kilogram.
Scientists from Vietnam National University spotted something unusual while examining specimens from seafood markets. Among the regularly caught species Bathynomus jamesi, six specimens stood out with distinctive features. These peculiar individuals showed several unique characteristics: a rectangular-shaped head region with parallel sides and a pointed tip, distinctively curved rear legs, and 11 upward-pointing spines along their tail segment. Perhaps most notably, they possessed rows of small bristles between these spines – a feature not typically seen in related species.
About the size of a football, the new species shares its habitat with its cousin B. jamesi in the South China Sea, particularly in the waters near the Spratly Islands. This coexistence of two giant isopod species in the same area mirrors similar situations observed in other parts of the world, such as the Gulf of Mexico, where multiple species live in the same deep-water environments.
In the early 2020s, Taiwanese restaurants featured them as premium ingredients, often incorporating them into noodle dishes. While Taiwan’s interest has since waned, Vietnam’s market continues to thrive, with restaurants across major cities maintaining specialized chilled tanks to keep these isopods alive for customers.
Most B. vaderi specimens were found approximately 50 nautical miles offshore from Quy Nhon City in south-central Vietnam. While the exact depths of their habitat remain unknown, these creatures typically live far below the ocean’s surface. Like their relatives, they serve as scavengers in the deep sea, playing a crucial role in marine ecosystems.
The growing culinary interest in these creatures has inadvertently advanced marine science. Without the flourishing seafood trade, this new species might have remained hidden in the depths of the South China Sea. It’s a remarkable example of how cultural practices and cuisine can contribute to scientific discovery, proving that sometimes the path to understanding our oceans’ biodiversity can run through local markets and restaurant kitchens.
And while Darth Vader came from a galaxy far, far away, at least we can take comfort knowing B. vaderi has been hiding much closer to home.
Paper Summary
Methodology Breakdown
Scientists obtained specimens through purchases from restaurants and local fishermen in various Vietnamese cities. They conducted detailed morphological examinations of six specimens identified as the new species, comparing them with known species using established taxonomic methods. They documented specific physical characteristics including the shape of the head region (clypeal region), leg structures, and tail (pleotelson) features.
Results Summary
The research definitively established B. vaderi as a new species based on several unique morphological characteristics. Key distinguishing features included parallel lateral margins in the head region, a narrowly acute apex, distinctively curved rear legs, and 11 upward-curved tail spines with setae (bristles) between them. The specimens ranged in size from 257 to 325 millimeters in length.
Study Limitations
The exact depth range and precise distribution of B. vaderi remain unknown due to limited collection data from commercial fishing operations. Additionally, no female specimens were collected, leaving aspects of sexual dimorphism and reproductive biology unknown. The reliance on commercially caught specimens may have created sampling bias.
Key Takeaways
This discovery brings the total number of known species with upward-curved pleotelson spines to four. The study highlights how commercial fishing activities can contribute to scientific discovery. The research also documents the growing economic importance of giant isopods in Vietnamese cuisine, with prices ranging from $27-80 per kilogram depending on size and market conditions.
Funding and Disclosures
The authors declared no competing interests and reported no funding for this research. No ethical statements were required for this study.
Publication Information
This research was published in ZooKeys (Volume 1223: 289-310) in January 2025, authored by Peter K. L. Ng, Conni M. Sidabalok, and Thanh Son Nguyen. The paper is available as an open-access article distributed under the terms of the Creative Commons Attribution License.
