Recent studies have managed to find the missing link that mediated the evolution of today’s flatfish. The name is quite graphical as it says a lot about the species; such fish (flounder and halibut for instance) live on the bottom of deep waters and their distinctive mark is the fact that their eyes are both placed on one side of the head.

There are currently more than five hundred species of flatfish populating both fresh and salty waters.

After having examined 45-million-year-old fossils, researchers found certain specimens displaying an obvious displacement of one eye, without reaching the other side of the head however.

On Thursday, considering the newly-found information, a report appeared in the journal Science which said flatfish have evolved gradually, and not through one mutation.

As flatfish represent one of the very few unsymmetrical vertebrates, a lot of attention has been given to the species by scientists; they have been trying to understand for quite a long time how their appearance managed to reach the current state.

As if this was not strange enough, it’s been noticed that young flatfish start off their lives with the eyes placed normally, on both parts of the head; as they grow, one of the eyes begins to migrate.

Study author University of Chicago doctoral student, Matt Friedman (28) showed, with the use of imaging technology, that the unusual placement of the eye was not due to alterations of the skull caused by the fossilization process, as initially thought back in the 19th century.