A new species of sexually dimorphic electric knifefish from the Amazon basin, Brazil (Gymnotiformes: Apteronotidae)

Abstract

Apteronotus lindalvae, a new species of sexually dimorphic electric knifefish, is described from the Rio Uatum, Amazon basin, Brazil. This is the first species of Apteronotus, outside the Apteronotus albifrons complex, known to inhabit rapids and waterfalls of Amazonian Rivers, being reophilic. The new species is distinguished from all congeners by a unique feature, the presence of an unpigmented dorsal stripe extending from the tip of the chin to beyond the posterior border of the eye, but never extending as far back as the branchial opening. It is also distinguished by the total number of anal-fin rays and the length of the caudal fin. The description of A. lindalvae increases to 19 the number of species in Apteronotus. © 2012 by the American Society of Ichthyologists and Herpetologists.