Meet the wood-boring clam – and, no, that’s not a euphemism.
In a study published in the Journal of Molluscan Studies, researchers led by Janet Voight from the Field Museum in Chicago, US, introduce three new genera and one entirely new species of this curious subset of clam.
The molluscs typically make their homes, and find their food, inside the decaying trunks of trees that have fallen down and floated out into the ocean.
Just like standard clams, the wood-boring varieties have bivalve shells. However, they also sport long external organs called siphons that allow them to reach back out into the ocean, there to pull water into their gills.
“There’s not just one tree-cleaner-upper in the ocean, they’re really diverse,” says Voight.
“Imagine living at the bottom of the ocean as a tiny swimming clam; you either have to find a sunken piece of wood or die. You wouldn’t think there’d be that many kinds of clams doing this. But we’ve now found that there are six different groups, called genera, and around 60 different species.”