Newsletter: Antingaw: Bohol's rock-eating shipworm vying for International Mollusc of the Year

[THIS IS A PRESS RELEASE]

FEATURED PHOTO: Antingaw, scientifically known as Lithoredo abatanica, or in English as the "Philippine Chalk-Chomping Clam," is one of five finalists for International Mollusc of the Year. Its serrated, stone-boring shells can clearly be seen on the right-hand side of the photo. 

The Philippines is a finalist for International Mollusc of the Year, and representing our country is one of the strangest and rarest species in the world. 

The antingaw is the first known shipworm that lives within and eats through rock. Closely  related to the tamilok and ugaong, it is unique in the shipworm family because it bores through limestone rather than wood. 

Despite the name, shipworms are a type of clam. Instead of being housed within their shell, shipworm evolution has resulted in a long, fleshy body with two jagged shells on its head—shells usually dedicated for boring into wood.  

What makes the antingaw distinct is that their shell has adapted to cut into stone: where other shipworms have teeth-like denticles that are small and sharp, the antingaw has denticles that are large and blunt. The 2019 paper that detailed the antingaw's discovery also found limestone in its stomach, making it the first known freshwater invertebrate that burrows through rock by ingesting it. 

The UP Marine Science Institute (UP MSI) is continuing this research and is currently leading the campaign for the antingaw to be International Mollusc of the Year. 

This is an annual competition hosted by the German research institute Senckenberg Society for Nature Research, its marine conservation arm Senckenberg Ocean Species Alliance, and the international research society Unitas Malacologica. The antingaw is vying for the prize together with candidate mollusc species nominated by the researchers of Italy, Australia, Seychelles, and the United States for the final stage. The results will be decided by public vote. 

The grand prize is a complete sequencing of the winner's genome. Having detailed genetic information will be a major step in using the antingaw to develop biotechnology products. 

UP MSI is already looking into creating biotechnology products with the antingaw and other shipworms with the support of the Department of Science and Technology - National Research Council of the Philippines.  

Through the "Teredinids and Associated Microbes: A Multi-level Investigation of Lifestyles and Outstanding Compounds as Sources of Novel Therapeutics" or TAMMILOC Project, UP MSI is investigating shipworms and the microbial symbionts that aid in wood digestion. 

A UNIQUE HOME. The burrowing holes in limestone made by the antingaw. The antingaw is exclusively found in the Abatan River, Bohol. 

The mechanism of how this odd animal gets nutrients from rock remains a mystery. Scientists think that the antingaw may harbor symbiotic microorganisms in its gills that help break down its inorganic diet, similar to how the tamilok hosts bacteria that helps break down mangrove wood. 

Exclusively found in the Abatan River of Bohol, the antingaw proudly carries its origins in its scientific name: Lithoredo abatanica Shipway, Distel & Rosenberg, 2019. 

All of the 2026 finalists are posted on the official website.  

The voting period for International Mollusc of the Year ends on April 26. Casting votes for the antingaw can be done through the official voting form.

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