The Lithoredo abatanica It is a curious freshwater mollusk with a very special diet. Unique in the world, it has been reported that this animal consume limestone and excrete sandstone. However, how does your intestinal mechanism work? How can you get nutrients from the stone itself?
Lithoredo abatanica is considered as a member of the shipworm group. Until now, species known as “shipworms” have been described as wood eaters.
Interestingly, these worms complete all or part of their life cycle in tunnels that dig into the wood. Thus, experts have determined that most species use wood as the main source of nutrition.
Shipworms are described in the literature since the fourth century B.C., being considered as the “nightmare” of sailors. Even now, due to their habit of drilling wood, they can cause significant damage to boats and docks.
Lithoredo abatanicaDo not eat wood but limestone
Unlike shipworms, their close relatives, the Lithoredo abatanica inhabit fresh waters. Its presence in the Abatan riverbed in the Philippines has been reported very recently.
They also distinguish themselves from their relatives in the fact that they do not dig in wood but in limestone rocks. After ingesting the stone, which accumulates in the entrails of the animal, it is pulverized and subsequently excreted as fine grained sand. Source: FayerWayer
The characteristics of this “rock worm” are so exceptional that the researchers had to recognize it not only as a new species, but as a new genus within the family of the Teredinids.
The strategy of Lithoredo abatanica Digging in the rock by ingestion represents a surprising mechanism, unique so far in the animal kingdom.
Ship worms, a misleading name
Despite its name, shipworms are not really worms. They are mollusks, a type of bivalve of the family Teredinidae, a group that includes various clams. These creatures have a very small shell at one end of their long and worm-shaped body.
The shell in this mollusk does not provide any protection for the elongated body of the animal. Rather, the pair of tiny leaflets has evolved to become a tool with which the animal scrapes the substrate it eats.
The animal’s digging tool has been adapted to do the work of cutting limestone, taking the form of dozens of small teeth. Thus begins the process of crushing the pieces of stone that these worms ingest.
Family eating in good company
- L. abatanica is related to another Teredinid, the Kuphus polythalamia a large creature -155 centimeters- that lives in the mud. This animal was found three meters deep in the sea in the Philippines.
- K. polythalamia A rather stinky place lives. Mud rich in organic matter emits significant amounts of hydrogen sulfide, a sulfur-derived gas.
So the feeding strategy of K. polythalamia it consists of resorting to beneficial bacteria – endobimotholes – that live in their gills, to obtain their nutrition. These bacteria oxidize sulfur and produce compounds that feed the worm.
What is the point of eating limestone?
Researchers do not believe that worms get nutrition from the rock. Instead, experts speculate that these mollusks can obtain nutrition from a symbiotic relationship with some bacteria.
It may be that unique bacteria that live in their gills or in the siphons for which the sandstone excretes, and provide them with products of their metabolism that the worm takes advantage of.
Experts also point out that the rocky particles in their bowels can help grind things like krill, similar to the way a bird’s gizzard works.
Lithoredo abatanica, masons of the river ecosystem
The habit of digging burrows of L. abatanica can play an important role in the configuration of the river ecosystem, by creating new habitats. In the case of shipworms, it is recognized that the labyrinth of tunnels dug by these creatures, provides shelter for fish and numerous marine invertebrates.
In this sense, the ecological impact of L. abatanica It is consistent with that of other Teredinids, as evidenced by two factors:
- The significant colonization of the bedrock: several invertebrate taxa were found that resided within the intricate network of built burrows
- The high fragmentation of this calcitic material that has spread across the Abatan river bank.
Thus, the presence of L. abatanica increases habitat complexity for a variety of species. In addition, it probably alters the course of the Abatan River.
Secrets of nature to unveil
There are still many mysteries to solve when it comes to the physiology of this new group of Teredinids. In the first place, studying their ecological habits could tell us a lot about how other organisms in their environment depend on the small crypts that this worm provides.
Because rock burrows can remain preserved for millions of years, their importance could be enormous. Understanding these modern masons can shed light on the evolution of the river ecosystem.
Finally, know if there is a microbiota, which colonizes L. abatanica, specialized in digesting rock can have huge biotechnological applications. This knowledge could constitute a new source of application products that foster economic development.