Scientists found a giant shipworm in the Philippines, marking the first time the animal’s habitat has been found. The elusive mollusk was searched for years, as scientists had found nothing but shell fragments and dead specimens.

The dead specimens were preserved in jars but had nearly dissolved. Despite this, scientists were puzzled about the giant shipworm, which takes its name from eating from the side of wooden boats. The tubular shell of the giant shipworm, which is actually a bivalve, measures about three feet long.

The elusive mollusk was searched for years. Image credit: Marvin Altamia / Science Alert
The elusive mollusk was searched for years. Image credit: Marvin Altamia / Science Alert

The findings were published in a study Monday in Proceedings of the National Academy of Science, where researchers describe a live giant shipworm for the first time. The study was led by Daniel Distel, a microbiologist from Northeastern University

Giant shipworm was found living at lagoon in the Philippines

The puzzling shipworm had never been caught, and Distel had been tracking it since 1989. The giant shipworm, or Kuphus polythalamia, had been described as the unicorn of mollusks, as it had been so difficult to find.

Researchers believe that the giant shipworm’s symbiotic relationship with bacteria provides evidence of how the mollusk evolved its strange way of feeding itself. The study also suggests that this evidence may enrich current understanding of infections in humans.

“We were used to shipworms which are very delicate creatures and much smaller,” said Distel, who looked for the animal for over two decades, according to The New York Times. “This thing is really a beefy animal.”

Distel was able to track down the animals after a student found a YouTube video that showed people eating the mollusk. A television news channel in the Philippines had aired a short documentary segment about a weird mollusk that lived in the lagoon. The film also showed mollusk growing in the muck, resembling rows of elephant tusks.

He contacted local researchers and local fishers, and they helped him locate the giant shipworm at the bottom of a lagoon. In that area, shipworms are considered a delicacy named tamilok that allegedly has medicinal properties. The team took a live shipworm out of the lagoon and took it to a laboratory for examination.

Diesel compares the discovery to finding the lost elephant graveyard or finding a dinosaur alive. The team uploaded a video showing the moment when they examined the giant shipworm. The task was difficult, as Distel had to crack the shell open carefully. Once he managed to break a part of it, he took the animal out of his shell and performed a dissection. The researcher said that it was pretty spectacular to lift the tube out of its container for the first time.

The shipworm lives off hydrogen sulfide

Giant shipworms can measure up to three feet long, which means that they become too large for their shell. Researchers said the shell is quite heavy, as it resembles a tree branch or something even heavier. The analyzed the mollusk’s small digestive system and supersized gills were speckled with yellow, most likely for sulfur. This led researchers to believe the animal lived off hydrogen sulfide, rather than off the wood they ate from the boats.

Distel and his team examined the genomes of the giant shipworm along with its bacteria, and the enzymes inside it. The team believes that shipworms first ate wood, but they acquired bacteria in millions of years of evolution. This bacteria allows them to mix an energy cocktail to obtain chemicals from the seawater, primarily hydrogen sulfide from decomposing wood, instead of eating the wood itself.

He noted that a similar symbiotic relationship also exists in a large mussel that lives in the deep sea that is believed to have grown so huge off energy obtained from chemicals instead of organic matter. This can be compared to how plants use sunlight, carbon dioxide and water in photosynthesis. Researchers say that this process is a highly rare example where they were able to find direct evidence about how that particular symbiosis evolved.

Findings could help with breakthroughs in medicine

Distel says that this unusual relationship could also have implications for medicine. The scientist explains that if humans have bacteria living in their cells, they’ll be sick. However, in the giant shipworm, either the bacteria evades the animal’s immune system, or the shipworm recognizes bacteria as safe.

“Understanding how an animal can live with bacteria inside their cells and not get sick and die, could help inform our understanding of infection,” said Distel.

The research team says that many more studies may be unveiled by further studying the giant shipworm and the bacteria inside it. The doctor adds that when someone finds something weird and unusual, more often than not, there’ll be some unexpected discoveries resulting from it.

Source: The New York Times