American scientists first found a shipworm, which does not live in wood, but in the limestone banks of the Philippine river. The intestines of the samples found were filled with calcite, a mineral from which limestone mainly consists. This may mean that the shipworm not only drills passages in the rock, but may even feed on it.
Shipworms are clams of the family Teredinidae, which are very different from the rest of their relatives. Their body looks like a worm’s body, the shell is small, and the whole fits on the front end of the body. With the help of a special intestinal microflora, shipworms digest the wood in which they drill passages with their sinks. These mollusks spoil ships and coastal buildings, causing damage of billions of dollars a year. However, they play an important role in coastal ecosystems by utilizing dead wood.
A new type of shipworm scientists have found and described in the Philippines. The mollusk, named Lithoredo abatanica, lives in the banks of the Abatan River, at a shallow depth – the samples were found about two meters under water. Animals from 5 millimeters to 10 centimeters long bore their shells in limestone with their shells. Unlike the shells of treeworm shipworms, the shells of the representatives of the new species are distinguished by a smooth edge, on which there are no small notches.
The intestines of mollusks were filled with crushed calcite, the elemental composition of which is identical to the composition of limestone (this rock consists of calcite crystals) in which the shipworm lives. Scientists have suggested that the mollusk feeds on minerals using a symbiotic microflora from chemotrophic bacteria. Some microflora in the intestine of a new species lives, but it has not yet been investigated, so it’s impossible to say for sure whether the microbes of the mollusk can digest the stone.
According to scientists, the find, at a minimum, can help paleontologists who, with the help of shipworm moves in petrified wood, understand that there was once a seashore at the excavation site. The existence of a new mollusk means that these passages in the rock are not necessarily tied to the sea, because the animal could have just drilled a stone in an ancient freshwater river.
In addition, scientists suggest that the clam may eventually change the course of the river in which it lives. As the authors write, a large number of highly fragmented calcite is scattered along the shores of Abatan, which, perhaps, indicates the work of the mollusk.