A newly-discovered species of catfish can use its fins for more than swimming. From the top side, Lithogenes wahari looks like any other catfish, except with some extra body armor. But flip it over and you’ll see a giant sucking mouth and a pair of fleshy pelvic fins, which it uses to grasp and shimmy up slippery rocks in fast-flowing rivers.
Scientists first laid eyes on the strange fish 20 years ago in Venezuela. But the only specimen they had was in such bad condition that it “looked like it had been run over by a truck,” recalls researcher Scott Schaefer. It took years before the team was able to locate more of the species, which they found in abundance in a tributary of the Orinoco river. Capturing L. wahari was easy: the researchers easily picked 84 specimens off of rocks.
The unusual morphology of L. wahari means it has similarities with two different families of catfish, say the researchers. For now, it is being classified in a special subfamily, Lithogeninae, which contains only two other members. The only other species of catfish known to use fins for vertical climbing is found in high elevation streams of the Andes mountains.
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Image: Scott Schaefer