sciencetech-blog

comments

While scientists have theories about how fish first crawled onto land and breathed air, it's a mystery as to how vertebrates evolved tongues instead of feeding using suction.

But now, a slow-motion video of mudskippers eating shrimp may help reveal the evolutionary secret.

It shows the creatures, which live in and out of water and forage for food on the ground, taking a mouthful of water to act like a tongue, allowing them to swallow food on land.

Scroll down for video 

A slow-motion video of mudskippers feeding may help reveal an evolutionary secret. It shows the creatures, which live in and out of water and forage for food on the ground (pictured in a stock image) taking a mouthful of water to act like a tongue, allowing them to swallow food on land

Experts believe the finding may shed light on how terrestrial tetrapods - four-legged vertebrates - with tongues evolved from fish between 400 and 250 million years ago.

When underwater, mudskippers suck water containing food particles into their mouths, which are swallowed when they reach the back of their throats, New Scientist reported. 

However, this method doesn't work on land, so terrestrial vertebrates evolved tongues to move the food to the back of the throat. 

A team of researchers led by Krijn Michel at the University of Antwerp, Belgium, captured slow-motion X-ray footage (shown) of Atlantic mudskippers eating pieces of brown shrimp out of water

The video revealed that mudskippers combine the sucking method of fish (stock image left) with the grabbing tongue action of amphibians such as nexts (right), meaning they could reveal a missing evolutionary link

A team of researchers led by Krijn Michel at the University of Antwerp, Belgium, captured slow-motion X-ray footage of Atlantic mudskippers eating pieces of brown shrimp out of water.

They found that it takes the gelatinous creatures less than half a second to pounce and eat.

By watching the video, which was slowed down 50 times, the experts were able to see that the mudskippers carry water in their mouths.

They spit it forward to grab the shrimp and then suck it back into their mouths quickly,to mimic the action of a tongue.

The team also placed food on an absorbent surface and found that the mudskippers could still grab the food using their unusual technique, but had problems swallowing it.

The scientists worked out that mudskippers move the hyoid bone in the floor of their mouth upwards, before they attempt to gulp down food.

Their finding is reported in Proceedings of the Royal Society B: Biological Sciences and is the opposite of what fish do underwater.

However, it closely resembles the feeding habits of newts, which have tongues.

This means that mudskippers combine the sucking method of fish with the grabbing tongue action of amphibians, so they could reveal a missing evolutionary link.

Dr Michel said: 'This could be an in-between, from which a fleshy tongue could have evolved.

'This has never been considered a possibility, until now.