If you think all molluscs have a shell, think again.
Introducing Solenogaster.
This is a small worm-like creature found in the deep sea. It belongs to the order Aplacophora. Specifically, it belongs to the suborder Neoserpenta. Unlike snails, clams and octopuses, solenogaster has no visible shell. Instead, the soft body is covered with a hard outer layer. This stratum corneum contains thousands of tiny calcium carbonate needles that act like miniature armor.
Most of these animals are barely visible to the naked eye. Its length usually does not exceed 2.5 cm. It is about 1 inch. Some grow larger, but even the largest species are about 30 centimeters long. 30 centimeters is the limit for creatures that look like an elongated carpet.
where do they live
they live in the deep sea. The depth varies from 30 meters to 1,800 meters. Located approximately 100 to 5,900 feet below the surface. It is rarely seen in shallow water. So far, researchers have identified about 240 different species.
But there’s a problem.
There is more to the Apracophora group than just spirochidia. There is another group. It is called a Phrozoan genus. This subcategory contains about 120 different species. These creatures are also shellless molluscs. They are often confused with large carp, but they belong to a separate evolutionary line within the same class.
So how do they lose their shell?
Evolution took them away from them. They traded strong protection for flexibility. Because they live in a dark, high-pressure environment, their heavy shells can be a burden. Their spikes provide good protection against deep-sea predators.
We have only scratched the surface of these animals. Many species have yet to be discovered. The deep sea is largely uncharted. New samples may change the classification method. Alternatively, you can simply add it to a known quantity.
What happens when you finally find a snail inside its shell?
Probably nothing. This definition breaks down. The mystery only deepens. This is how science works. One question leads to another. The deep sea hides secrets.
