Lurching lungfish suggest underwater start for four-legged locomotion
African lungfish walk and bound along the bottoms of water tanks on their slender, whiplike pelvic fins, a new study finds.
Because lungfish are closely related to some of the earliest four-legged terrestrial vertebrates known as tetrapods, such findings may indicate that transitional creatures learned to scuttle across the floors of ancient seas before they took to land and developed more complex limbs with digits, biologist Heather King and colleagues at the University of Chicago suggest online December 12 in the Proceedings of the National Academy of Sciences.
“The cool thing about the lungfish is that it’s walking underwater,” says King. “And if lots of tetrapods were also doing this it could mean that the first step in the evolution of vertebrate walking took place underwater.”
Around 400 million years ago, certain species of bony fish — called the lobe-finned fishes for their characteristic muscu