‘Rare’ new fish species — with dangly, long lips — discovered in river in Amazon

A rare new species of fish was recently discovered prowling the bottom of a river in the Amazon rainforest, researchers said.

The creature — a yellow-hued, flat-bodied catfish — is distinguished by its strange lips, according to a study published on April 9 in the Journal of Fish Biology.

During an expedition in the western Brazilian state of Amazonas, a team of international researchers pulled eight specimens of a then-unknown catfish species from the Rio Negro, a tributary of the Amazon River.

The fish was determined to be a member of the genus Rhadinoloricaria, which is made up of catfish exclusively from South America.

Peculiar protrusions on the creature’s lip indicated it was a previously undocumented species.

The protrusions, known as elongated papillae, are fleshy tendrils that dangle from the catfish’s bottom lip, and appear to be unique to the genus. Researchers named the fish Rhadinoloricaria papillosa in a nod to its uncommonly long papillae.

It’s not clear what purpose the papillae serve, but other fish, a species of cavefish in particular, use sensory papillae to navigate, according to the National Park Service.

Unbranched barblets, which are shorter protrusions sprouting from the fish’s lip, also appeared unique, and suggested the fish belonged to a novel species. DNA analysis confirmed the researchers’ suspicions.

Researchers concluded that the new species was rare because over the course of a 10-day expedition, only eight specimens were caught. They recommended that it be categorized as endangered.