A rare knifefish has been brought back out of synonymy over 140 years after it was discovered.
Sternopygus obtusirostris, a species known as the Longtail knifefish, is a member of the South American knifefish family Sternopygidae. It was originally collected in 1865 by Louis Agassiz and described by Steindachner in 1881. However, a number of subsequent studies suggested that the species had been confused with another, so it was considered a synonym of S. macrurus.
A recent study by Crampton, Hulen and Albert, published in the latest issue of the journal Ichthyological Exploration of Freshwater says that S. obtusirostris is, in fact, a valid species in its own right.
The fish, which uses electricity for navigation is found in blackwater regions of South America including the Rio Negro, Tefe, Amazonas and Para.
For more details see: Crampton, W., Hulen, K. and J. Albert (2004) - Redescription of Sternopygus obtusirostris (Gymnotiformes: Sternopygidae) from the Amazon basin, with description of osteology, ecology and electric organ discharges. Ichthyological Exploration of Freshwaters. Vol. 15. No.2 121-134.