Sternarchella calhamazon n. sp., the Amazon's most abundant species of apteronotid electric fish, with a note on the taxonomic status of Sternarchus capanemae Steindachner, 1868 (Gymnotiformes, Apteronotidae). Proceedings of the Academy of Natural Sciences of Philadelphia, 162, March 2013: 157-173. 159 [Zoological Record Volume 149]