A previously unknown species of climbing catfish has been discovered in remote Venezuela, and its strange traits are shaking the evolutionary tree for these fish.
The newfound catfish, Lithogenes wahari, shares traits with two different families of fish — Loricariidae (armored catfishes) and Astroblepidae (climbing catfishes). It has bony armor that protects its head and tail, and a grasping pelvic fin that helps it to climb vertical surfaces such as rocks.
But L. wahari also has a specialized pelvic fin that decouples from its body and moves backward and forward independently. This feature — used in combination with a grasping mouth to move like an inchworm up rocks — is otherwise found only in a family of climbing catfish restricted to the Andes, the Astroblepidae. Climbing could be an advantage to these fishes because of the irregular and sometimes high-flow of streams in these elevations.
Read more about it at MSNBC.com