Media note: A photo of Electrophorus voltai in the Xingu River can be found at https://cornell.box.com/v/neweelspecies
Newswise — ITHACA, N.Y. – Scientists have discovered two new species of electric eel, one of which delivers the highest level of electricity generated by any living creature.
The two new species are named Electrophorus varii and E. voltai. E voltai generates 860 volts, which is quite a bit more than the 650 volts recorded from the third, and longest known, species, E. electricus, which was first described by zoologist Carolus Linnaeus 250 years ago. Since then it was mostly assumed that E. electricus was the only species that existed – and that it was widely distributed across Greater Amazonia.
“Eight hundred and sixty volts is an incredible output of electricity for an animal,” said Casey Dillman, curator of fishes, amphibians and reptiles at the Cornell University Museum of Vertebrates and co-author of a study published Sept. 10 in Nature Communications describing the discoveries. “Our electric plug points are 110 volts.”
Researchers wanted to determine whether only one species of electric eels occurred throughout the vast geographic area of the Amazon basin and the more northerly Guiana shield. To test the idea of a single widespread species, the team collected 107 new specimens from a network of collaborators throughout South America and Europe.
The three species are very similar in appearance, and thanks to technological advances that provided new genetic, morphological and ecological data, the team identified the two new species.
All three species have a Sach’s organ, for low voltage electric discharge, and a Hunter’s organ, which generates high voltage electric discharge. The Sach’s organ is used for communication, and the Hunter’s organ is used for hunting.
Both E. electricus and E. voltai live in fast-moving water with fewer dissolved ions and minerals, and both have stronger electric discharges than E. varii, which lives in lowland waters with more dissolved particles, making the water more conductive.
“I suspect that in order to get the same reaction from the fishes they are going to eat, they have to have this higher voltage because the water is less conductive,” Dillman said.
David de Santana (a researcher in the Department of Vertebrate Zoology at the National Museum of Natural History in Washington, D.C. and lead author of the study) and Dillman received a five-year, $1 million grant from São Paulo Research Foundation/Smithsonian Institution to revise, update and discover the diversity of Gymnotiformes. One goal of the grant is to collect samples from eight areas in the Amazon basin that have not been previously inventoried.
For more information, see this Cornell Chronicle story.
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