Spiky predator with ‘forked’ teeth found lurking in Brazil river. It’s a new species
Equipped with oxygen hoses, divers plunged into the depths of a river in northern Brazil. They swam through the dark water looking for “assacu-preto,” a thorny black fish sold in the aquarium trade and, as scientists later discovered, a new species.
Fishermen along the Xingu River have been familiar with assacu-preto fish for years, but these spiky predators only recently caught the attention of a team of researchers, according to a study published Oct. 17 in the peer-reviewed journal Neotropical Ichthyology.
Researchers set out to survey catfish diversity in the Xingu River and quickly realized that the assacu-preto fish looked unique, the study said. The team worked with local fishermen and scoured museum collections to find dozens of these unfamiliar animals.
After analyzing the fish, researchers realized they’d discovered a new species: Pseudacanthicus nyktos, or the night armored catfish.
Night armored catfish can reach almost 10 inches in length, the study said. They have “completely black” eyes, “forked” teeth and “rounded” snouts. Their bodies are covered with armor-like “plates” and thorn-like spikes.
Photos show the “dark brown to black” coloring of the new species. Blotchy gray stripes crisscross its body and fins.
Night armored catfish live in the center of the river and are commonly found around “submerged logs” at depths of up to 65 feet, researchers said. These fish are carnivorous, feeding on “small aquatic invertebrates.”
The new species has a “territorial nature,” with male catfish becoming aggressive “when they share the same environment,” the study said. The males also “confine females within burrows until egg-laying is complete.”
Researchers said they named the new species after the Greek word “nyktos,” meaning “night,” because of its dark coloring and deep habitat.
Night armored catfish are “primarily found” in the lower Xingu River but occasionally have been spotted elsewhere due to “aquarium trade companies’ release of unsold specimens,” the study said. The river winds through several states in northern Brazil.
The new species was identified by its teeth, skeleton, coloring and other subtle physical features, the study said. Researchers did not provide a DNA analysis of the new species.
The research team included Maria Letícia Batista Galvão Lopes, Leandro Melo de Sousa and Carine Cavalcante Chamon.
This story was originally published October 22, 2024 at 11:42 AM with the headline "Spiky predator with ‘forked’ teeth found lurking in Brazil river. It’s a new species."
