Sea fish have ‘wings’ like birds and ‘legs’ like crabs

Crested fish are very good at finding prey while walking on the seabed using their six leg-like appendages, so much so that several other fish species follow them, waiting for an opportunity to feed. This is the result of two new studies published on September 26 in the journal Current Biology.

David Kingsley, co-author of both studies and a professor at Stanford University School of Medicine, first saw the crested fish in the summer of 2016, after attending a workshop at the Marine Biological Laboratory in Woods Hole. , Massachusetts, USA. Before leaving to catch his flight, Kingsley stopped by a small aquarium and encountered a crested fish.

“The crested fish completely amazed me because they had the body of a fish, the wings of a bird and many legs like a crab. I had never seen a fish that looked like it was made up of parts from many different animals.” like that,” Kingsley said. He and his colleagues decided to study them in the laboratory.

The distinctive legs of the crested fish are actually extensions of the pectoral fins, according to study co-author Amy Herbert, a postdoctoral researcher in Kingsley’s lab at Stanford University. Some other types of fish also have modifications in their pectoral or pelvic fins to help them walk or stand, but crested fish can move each leg separately, making walking and digging more effective.

Experts brought several crested fish back to the lab of study co-author Nick Bellono, a professor at Harvard University, to study and see if they could find buried prey. They found they alternated between short bursts of swimming and walking. They also scratch the sandy surface at the bottom of the tank to feed without any visual cues about the location of their prey.

To continue research, experts brought back more crested fish, but quickly realized they were not the same as the original group of fish. The new group did not dig or find buried prey.

This provides serendipitous discoveries for researchers. The original fish was the northern crested fish (Prionotus carolinus). The fish species that lacks the ability to feel and uses its legs mainly for walking is the striped crested fish (Prionotus evolans).

The crested fish can give scientists the opportunity to study how new body parts appear during evolution, how new characteristics appear, how the brain evolves and adapts to changes so, according to study co-author Corey Allard, an expert at Harvard University. “These strange little fish have a lot to offer that we probably can’t find from more conventional research organisms, such as mice,” he said.