‘Banjo’-shaped creature found ‘buried’ in Argentina riverbed. It’s a new species
In a river of northwestern Argentina, a “banjo”-shaped creature with “small” eyes tucked itself into the sandy riverbed or tried to, at least. Something nearby caused a “vigorous disturbance” and dislodged it.
Visiting scientists caught the aquatic animal — and discovered a new species.
A team of researchers visited several sites in the Bermejo River basin, an emerging biodiversity “hotspot,” between 2014 and 2024 as part of a project to survey aquatic life, according to a study published Sept. 3 in the peer-reviewed journal Ichthyology and Herpetology.
During the visits, the team used “electrofishing” to temporarily stun any nearby fish then collected some specimens with a net, the study said. Among the catch were a few brown patterned fish which didn’t match any known species.
Researchers realized they’d discovered a new species: Ernstichthys casalinuovoi, or Casalinuovo’s banjo catfish.
Casalinuovo’s banjo catfish have “depressed,” or flattened, bodies measuring about 2 inches in length, the study said. The overall shape is “similar to the shape of a banjo,” a type of musical instrument. Their eyes are “small,” and their mouths are “toothless.”
Photos show the brown coloring of the new species, which varies from darker brown to brownish orange. Most catfish have several thick black bars on their backs and tails. A few catfish also have scattered brown spots, the study said.
Casalinuovo’s banjo catfish were found in shallow “fast flowing waters, with sandy to gravel bottom,” “near woody debris along the muddy riverbanks” and in pools with “gravel bottoms,” researchers said. The fish /ere /caught individually indicating that they do not form schools” and “often found buried and captured after vigorous disturbance of substrate.”
Researchers said they named the new species after the late Miguel Angel Casalinuovo, an Argentinian ichthyologist and “dear friend and colleague,” who helped them collect “some specimens of the species.”
So far, Casalinuovo’s banjo catfish have been found at four sites in the Bermejo River basin of northwestern Argentina, near the borders with Bolivia and Chile.
The research team included Gastón Aguilera, Guillermo Terán, Alejandro Méndez-López, Martín Miguel Montes and Tiago Carvalho.
This story was originally published September 12, 2025 at 8:34 AM with the headline "‘Banjo’-shaped creature found ‘buried’ in Argentina riverbed. It’s a new species."
