Philippines’ rock-eating ‘antingaw’ vies for International Mollusc of the Year

The Philippines has been named a finalist for International Mollusc of the Year, represented by one of the strangest and rarest species known to science: the Antingaw.

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

Despite the name, shipworms are a type of clam. Instead of living inside a typical shell, shipworms evolved long, fleshy bodies with two jagged shells at the head, usually used for boring into wood.

What makes the antingaw distinct is that its shell has adapted to cut through stone. While other shipworms have small, sharp tooth-like denticles, the antingaw has larger, blunt denticles. A 2019 study detailing its discovery also found limestone in its stomach, making it the first known freshwater invertebrate that burrows through rock by ingesting it.

The University of the Philippines Marine Science Institute is continuing research on the species and is leading the campaign for the antingaw to win International Mollusc of the Year.

The annual competition is hosted by the Senckenberg Society for Nature Research, its marine conservation arm Senckenberg Ocean Species Alliance, and Unitas Malacologica. The antingaw is competing against species nominated by researchers from Italy, Australia, Seychelles and the United States. Winners will be decided through public voting.

The grand prize is complete genome sequencing of the winning species. Researchers said detailed genetic information could help advance biotechnology products using the antingaw and other shipworms.

Through the TAMMILOC Project, UP MSI is studying shipworms and the microbial symbionts that aid in wood digestion and may unlock novel therapeutic compounds. Scientists also believe the antingaw may host microorganisms in its gills that help process nutrients from rock.

The species is found exclusively in the Abatan River and carries that origin in its scientific name, Lithoredo abatanica.

Voting for International Mollusc of the Year ends on 26 April through the contest’s official website.