Lithoredo abatanica is an organism with an unusual appetite: This creature eats stone. And when it excretes, what comes out is sand, the leftovers of a still-mysterious digestion process.

The mollusk, unearthed from the bottom of a river in the Philippines, was introduced this week by an international group of scientists in Proceedings of the Royal Society B. It is a shipworm, a group of burrowing animals related to clams, but so different from known examples that it is both a new species and genus.

Shipworms are usually known for their habit of eating wood. It’s right there in the name: They use their shells, attached to one end of their bodies, as chewing devices to burrow into and consume ship bottoms, docks and any other submerged wood . The behavior has made them the plague of mariners past and present, and in recent times, they have even sampled the delights of at least one New York City pier.

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Wood-eating shipworms fascinate scientists because they digest pulverized wood with the help of symbiotic bacteria that live in their gills. The bacteria manufacture an array of enzymes and other substances, and studying them and finding new shipworms may prove helpful in the search for new antibiotics, a subject of interest to the scientists behind the new paper.