04-03-2025
Toothless ‘electric' creature found in shallow river in Brazil. It's a new species
In a shallow stream of northern Brazil, a toothless 'electric' creature weaved its way through the tangled roots and dead leaves of the riverbed. Its 'large' eyes scanned its surroundings, but it wasn't the only one searching.
Passing scientists noticed the lurking animal — and discovered a new species.
A team of researchers spent over 20 years visiting dozens of rivers, streams and flooded plains of northern Brazil. Their goal? Document the region's fish diversity, according to a study published Feb. 28 in the peer-reviewed journal Acta Amzonica.
During their surveys, researchers found some 'weakly electric' fish with 'small' snouts, the study said. At first glance, the fish looked like another known species, but when researchers looked closer, they noticed some subtle but consistent differences.
The team had discovered a new species: Microsternarchus javieri, or Javier's electric knifefish.
Javier's electric knifefish are considered 'small,' reaching just over 4 inches in length, the study said. They have scaly, 'elongated' bodies ending in a thin, string-like tail. Their jaws 'lack teeth,' and their eyes are 'large.'
Photos show the yellow-brown hue and unusual body shape of the new species. Some fish had 'lighter and more translucent' bellies, revealing their internal organs, researchers said.
As their name suggests, Javier's electric knifefish have an 'electric organ' that emits 'electric discharges,' the study said. These charges vary between male and female fish and, during breeding season, can be clearly differentiated from the discharges of another common electric fish species.
'Such differences in (electric organ discharges) can be important in species recognition and in signaling sexual identity, sexual maturity, and motivational state,' the study said. Researchers could only identify these differences 'after laboratory analyses' and don't know how — or even if — electric fish themselves can identify different signals 'in the wild.'
Javier's electric knifefish live in shallow rivers and streams 'with slow currents' and 'a great abundance of dead leaves, abundant roots, leaf litter, vegetation cover, and tangled roots,' the study said.
Researchers said they named the new species after the late scientist Javier Maldonado Ocampo because his 'research on gymnotiforms (the fish group which includes the new species), systematics, and conservation greatly contributed to our understanding of the Neotropical ichthyofauna.'
So far, Javier's electric knifefish have been found at dozens of sites in the neighboring states of Roraima and Amazonas in northern Brazil, the study said. These states border Colombia, Guyana, Peru and Venezuela.
The new species was identified by its size, skeleton, fin shape, eyes and other subtle physical features, the study said. DNA analysis found the new species had at least 12% genetic divergence from other related fish species.
The research team included Carolina Escamilla Pinilla, Cristina Cox Fernandes and José Antônio Alves-Gomes.
