A 30 million-year-old fossil has revealed how suckerfish evolved the sucker that enables them to stick to other fish and hitch a ride.
Previous evidence led scientists to believe it must be a modified fin, but the evolutionary steps that led from fin to sucker were a mystery.
Now Oxford University researchers have studied an early fossil and found it evolved a fully-functioning sucker on its back.
It was only later in the suckerfish’s evolutionary history that the sucker migrated to the top of the head, where it is found today.
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