A new species of electric eel with the most powerful shock of any animal ever discovered has been found in the Amazon.
The creature is one of three species now confirmed to exist. For the last 250 years, since electric eels were first identified, it was thought there was just one species in the genus.
In a study published in Nature Communications, researchers led by C. David de Santana, from the Smithsonian's National Museum of Natural History, analyzed over 100 fish collected across Greater Amazonia over recent years to find out if it is indeed just one species.
The electric eel—which is not a true eel, but rather a South American knifefish—can generate pulses of electricity it pushes through water to shock prey and defend itself. The ability of animals to produce electricity is known as bioelectrogenesis. Other species known to possess this ability include certain catfish, stargazers and rays. The electric eel, however, generates the biggest voltage—around 650 volts.
In the study, Santana and colleagues looked at the morphology of the electric eels collected, performed an analysis of their DNA and examined their geographical and ecological distributions.
Findings revealed not one but three distinct species of eel, which they have named Electrophorus electricus, Electrophorus varii and Electrophorus voltai. The latter was found to produce the biggest shock of all, reaching 850 volts. This is the biggest discharge produced by any bioelectrogenetic animal ever recorded. Each species was found to have individualized skulls, pectoral fins and arrangement of pores across its body.
The three were found to have slightly different ranges—E. electricus is generally found in the Guiana Shield, E. varii and the Amazon basin lowlands, while E. voltai tended to be found in the Brazilian Shield. The three creatures split from a common ancestor during the Miocene and Pliocene (23 to 2.5 million years ago), researchers say. E. varii split off around 7.1 million years ago, while E. voltai and E. electricus diverged about 3.6 million years ago—a time when the Amazon River changed course. The scientists think E. voltai's higher voltage is an adaptation because it lives in highland waters that are less conductive.
In a statement, Santana said the discovery of the new species could provide an insight into a new system for electrogenesis—when it was discovered, the electric eel helped inspire the design of the first-ever battery. "It could really have different enzymes, different compounds that could be used in medicine or could inspire new technology," he said.
"These fish grow to be seven to eight feet long. They're really conspicuous. If you can discover a new eight-foot-long fish after 250 years of scientific exploration, can you imagine what remains to be discovered in that region?"