Scientists have carried an experiment to shed light on the evolutionary process of a unique African fish that can live both in water and on land.
Dragon fish, also called Polypterus senegalus, is very different from other species of fish as it has two lungs that allow it to survive outside the aquatic environment.
Scientists carried an eight-month experiment to find out what happens to the Dragon fish when they are raised outside of water.
The researchers say the fish changed notably as they started showing key differences in their body parts, like bones and muscles, which help the fish in movement on land. These features were not shown in those fish which were raised in water.
According to the study researchers, the fish moved on to dry land around 400 million years ago to evolve into quadruped vertebrates.
The unique Dragon fish is a living demonstration of a phenomenon called developmental plasticity, which states that physiology of a creature can be changed by environmental factors and with the passing time these changes are incorporated in to the genome of the animal.
The main aim of the experiment was to find out what are the physical changes on Dragon fish when they are raised outside the aquatic environment.
“We wanted to push them in this new environment to see if we could reveal this cryptic variation and if it works, what does it look like,” said Hans Larsson, of McGill University’s Redpath Museum.
The study showed that the Dragon fish which were raised outside water were very similar to those first emerged from the ocean. These fishes were placed in a tank with just 1mm of water. The vegetable misters were used to keep the fish damp.
After the eight-month study period, the researchers found that the fish raised outside the aquatic environment undergone several physical changes like they became more skilful at walking without losing their swimming skills. Moreover, they started positioning their pectoral fins near the center of their body. They also started demonstrating an elongation of their ‘chest’ area to separate it from their skull.
The research paper was published in the journal Nature.