- Researchers have described six new species of catfish from the Amazon and Orinoco river basins in South America.
- All six species belong to the genus Ancistrus, and have tentacles sprouting from their faces, spines sticking out from their heads, and armor-like bony plates covering their bodies.
- The newly described fish were once plentiful but are now scarce, the researchers say, largely due to habitat destruction from agricultural expansion, deforestation and gold mining.
From the Amazon and Orinoco river basins in South America, researchers have described six new species of catfish that have tentacles on their faces, spines sticking out from their heads, and bodies covered with armor-like bony plates.
All six species belong to the genus Ancistrus, researchers report in a new study published in Zootaxa. These river-dwelling catfish, commonly known as bristlenose or bushynose catfish, are popular aquarium fish, particularly famed for their skills as champion algae eaters that help keep tanks clean.
All members of this group also have several fleshy tentacles covering their snouts — a feature that distinguishes them from other catfish that tend to have smaller “whiskers.” Males have especially long tentacles on their snouts. And researchers think the larger tentacles come in handy when trying to attract females.
This is because Ancistrus fathers guard the nests of eggs and juveniles against intruders. To females, a male that’s guarding a nest might signal a fitter parent that knows how to take care of its young. Researchers have posited that the long tentacles in males, which resemble larvae or catfish juveniles, might have evolved to trick a female into laying eggs in the nest.
“The idea is that when a female fish sees a male with these tentacles … [t]hat signifies to her that he’s a good father who’s able to produce offspring and protect them,” Lesley de Souza, a fish expert at Chicago’s Field Museum and lead author of the paper, said in a statement. “It’s an evolutionary move that takes ‘catfishing’ to a whole new, kind of sweet level.”
One of the new species, A. patronus, in fact gets its name from the Latin word for “protector,” in reference to the male’s parenting skills.
All of the six newly described species can be found in clear, fast-moving rivers in northeastern South America, in parts of Venezuela, Colombia and Guyana. Where they were once abundant, the fish are now scarce, the researchers say, largely due to habitat destruction from agricultural expansion, deforestation and gold mining.
“Miners dredge up the river bottom causing increased sediment load, this changes the habitat structure of the river system, thus impacting the fishes’ ability to survive,” de Souza said. “Another effect from gold mining is the use of mercury to extract the gold in the river. This impacts all wildlife and principally local people that consume these fishes and other species in the watershed.”
Putting a name on previously undescribed species can kick-start their conservation, de Souza added. For instance, one of the new species, A. kellerae, named after Connie Keller, the former chair of the Field Museum’s board of trustees, is known only from the highlands of Guyana. “There are current threats to its ecosystem by gold mining, but now that it has a name we can try to push for conservation protection of the area with this endemic fish species,” de Souza said. “Everything begins with naming a species and determining how many species you have. Once you have done the taxonomy then you can study the ecology, behavior, and do conservation action.”
De Souza, L. S., Taphorn, D. C. and Armbruster, J. W. (2019) Review of Ancistrus (Siluriformes: Loricariidae) from the northwestern Guiana Shield, Orinoco Andes, and adjacent basins with description of six new species. Zootaxa. 4552(1).