Pictures: New Armored, Wood-Eating Catfish Found in Amazon

Fresh Catch

Photograph courtesy Paulo Petry

Nature Conservancy scientist Paulo Petry holds up a rare whole specimen of a newly identified species of wood-eating catfish, netted by Peruvian biologist Roberto Quispe at the confluence of the Alto Purús and Curanja Rivers in summer 2010.

According to the University of California's German, who wasn't involved in the new study, previous specimens "were dried by the people who caught them, so all that was available were these large dried specimens or smaller individuals."

While the unnamed species is new to science, the fish is a familiar food to indigenous people of the Amazon, especially in Peru (Amazon interactive map).

"They put it in soup or barbecue it whole," German said. "The fish have an armor shell that acts like a built-in bowl. So they take out the gut and cook the fish whole and just eat the meat out of the shell."

Most wood-eating catfish belong to the genus Panaque, as does the new species, which can grow at least 2.5 feet (80 centimeters) long.

(See pictures of the world's largest catfish.)

Published September 21, 2010

Log's-Eye View

Photograph courtesy Paulo Petry

A member of the new species of armored, wood-eating catfish—netted in the Peruvian Amazon in summer 2010—shows off the spoon-like teeth and suctioning lips that help the fish gouge out log shavings.

Wood-eating catfishes' unique diet likely evolved due to competition with other catfish species for food in the Amazon Basin rivers, researchers say.

"There're not a lot of rocks in the Amazonian Basin, where these fishes live," German said. "There's mud and water, and the one consistent substrate at the bottom is wood. It's the one place where fish can go to get food off a surface."

There are about 700 species of catfish that survive by scraping organic material from surfaces, including wood, in the Amazon Basin. But by actually ingesting the wood, wood-eating catfish take advantage of the organic matter, microbes, and microbial byproducts that reside in the spaces between wood fibers.

"The ability to dig and gouge then becomes advantageous," German said, "because now you can get to all these other goodies that surface eaters can't get."

(Also see "Twelve Hundred-Plus Venomous Catfish Species Uncovered.")

Published September 21, 2010

Jaws 4

Diagram courtesy Nathan K. Lujan and Julian Humphries

The four stout jaws of the new wood-eating catfish species are clearly visible in this 3-D image of its head, which was made by sticking the fish into a specialized CT scanner.

"Once they latch on with their lips, they can move those teeth around in all sorts of different directions to grind up the wood," German explained.

"They're not ingesting giant splinters. It's mainly small shavings and particles of wood, along with microbes and whatever byproducts the microbes are making available as they degrade the submerged wood."

(Related: "New Catfish Species Found in Mexico.")

Published September 21, 2010

Prickly Character

Diagram courtesy Max Hidalgo and Nathan K. Lujan

Adult male members of many wood-eating catfish species—such as this specimen of the new species, caught in Peru in 2006—have bristly appendages on their fins and on their heads.

"The brushlike features are specialized teeth called odontodes," said Texas A&M University biologist Nathan Lujan, lead author of the study describing the new species. "They are used in sexual and territorial threat displays."

(Also see "Fish Lives in Logs, Breathing Air, for Months at a Time.")

Published September 21, 2010