North Sea robins use their feet to search for food on the ocean floor
Annick Grierson
This impressive fish from the bottom of the Atlantic Ocean evolved legs, but not just for walking. These appendages are new tongue-like sensory organs that are used to find prey buried on the ocean floor.
North Sea Robin (prionotus carolinus) It has three legs on each side of the body, which protrude from the base of the pectoral fins. The legs are derived from structures within the pectoral fin called fin rays.
During a research trip to Woods Hole, Massachusetts, Nicholas Verono Researchers at Harvard University heard about the robins’ hunting abilities and decided to take some live specimens back to their lab.
The researchers wanted to see if this fish was as good at finding prey as it was known to be. “Surprisingly, they were so good at it that they were even able to discover capsules containing ground and filtered mussel extracts and single amino acids,” Bellono says.
The researchers then collected more fish, and found that the second group was better at walking, but worse at detecting prey buried in the sand.
“This time, the new robin was unable to find anything, even though it quickly ate prey on the surface,” Bellono said. “I thought I might have done something wrong, but it turns out I accidentally got the wrong kind.”
The team accidentally collects striped robins (prionotus evorans), They walk, but specialize in hunting unburied prey.
“When we looked at burrowing and non-burrowing animals, the legs were clearly different, and the sensory papillae on the burrowing legs were clearly visible,” Bellono said.
These papillae are bulges that contain taste receptors and touch-sensitive neurons, similar to the papillae that make up the taste buds on the human tongue.
A variety of other fish have evolved modified pectoral and pelvic fins that allow them to walk and perch, team members say. amy herbert At Stanford University, California. “But a unique feature of robins is that whereas other fish usually use the entire pectoral or pelvic fin for this purpose, the robin’s legs can move independently and very quickly, especially when walking. It’s about being adept at digging holes,” she says.
The research team also investigated the genes that drove the evolution of robins’ unique legs and found that their development was controlled by an ancient regulatory gene called . tbx3a.
“It is typically expressed in specific localized areas in the fins and limb buds of everything from fish to mammals,” the team members say. david kingsleyalso at Stanford University. “This is a great example of modifying an old shared tool to create new body parts.”
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