|de Santana , Wosiacki , Crampton , Sabaj , Dillman , Mendes-Júnior & Castro e Castro , 2019|
Electrophorus varii is a species of electric eel ( Electrophorus ) that occurs in the Amazon lowlands from the Ecuadorian and Peruvian Andes in the west to the mouth of the Amazon in the east. The first description of the species appeared in September 2019 after it was discovered that under the name Electrophorus electricus ,introducedby Carl von Linné in 1766, there were three cryptic species that are very similar in appearance, but clearly different genetically. Electrophorus varii was named in honor of the American ichthyologist Richard Peter Vari (1949-2016). Terra typica is the Rio Goiapi on the island of Marajó in the mouth of the Amazon.
Electrophorus varii reaches an average length of one meter; the longest specimen examined for the first description was 148 cm long. The body height is 4.1 to 10.8% of the total length, the width of the body is 4 to 8.1% of the total length. The head length is 8.1 to 14.2% of the total length. The head is narrow compared to that of Electrophorus voltai when viewed from above or below, but higher when viewed from the side. The cleithrum , a pair of cover bones in the fish's shoulder girdle, is located between the first and second vertebrae; in the other two electric eel species, it is located between the fifth and sixth vertebrae. The long anal fin is supported by 320 to 395 fin rays (325 to 386 in Electrophorus electricus and 320 to 420 in Electrophorus voltai ), the pectoral fins have 20 to 28 fin rays (32 to 38 in Electrophorus electricus and 23 to 31 in Electrophorus voltai ). The sideline is accompanied by 124 to 186 scales (88 to 101 in Electrophorus electricus and 112 to 146 in Electrophorus voltai ). A light band along the sides of the body, which occurs now and then in the other two electric eel species, is always missing in Electrophorus varii . The highest voltage measured when the electrical organs were discharged was 572 volts . The specimen on which this tension was measured was 60.9 cm in length.
In the habitat of Electrophorus varii in the Amazon lowlands , the water is usually poor in oxygen, the rivers flow sluggishly, the soil is sandy or muddy, and there are no rapids and waterfalls. In white water rivers the electrical conductivity is high (60–350 µScm), in black water rivers it is low (<30 µScm).
- C. David de Santana, William GR Crampton, Casey B. Dillman, Renata G. Frederico, Mark H. Sabaj, Raphaël Covain, Jonathan Ready, Jansen Zuanon, Renildo R. de Oliveira, Raimundo N. Mendes-Júnior , Douglas A. Bastos, Tulio F. Teixeira, Jan Mol, Willian Ohara, Natália Castro e Castro, Luiz A. Peixoto, Cleusa Nagamachi, Leandro Sousa, Luciano FA Montag, Frank Ribeiro, Joseph C. Waddell, Nivaldo M. Piorsky, Richard P. Vari & Wolmar B. Wosiacki: Unexpected species diversity in electric eels with a description of the strongest living bioelectricity generator. Nature Communications, Volume 10, Article number: 4000 (2019), doi: 10.1038 / s41467-019-11690-z