A New Species of Sexually Dimorphic Electric Knifefish from the Amazon Basin, Brazil (Gymnotiformes: Apteronotidae)
Apteronotus lindalvae, a new species of sexually dimorphic electric knifefish, is described from the Rio Uatumã, 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.
Holotype of Apteronotus lindalvae, INPA 27688, male, 250 mm TL (top), Brazil, Amazonas, Rio Uatumã, Cachoeira do Mirití; and paratype, INPA 15977, female, 168 mm TL (bottom).
Map showing the geographical distribution of Apteronotus lindalvae (star = type locality).
Plot of the first and second principal components of 68 specimens of Apteronotus lindalvae derived from PCA of 20 morphometric measurements (square = immature; circle = females; triangle = males).
Contributor Notes
Associate Editor: R. E. Reis.