Abstract
A new species of Neotropical electric fish, Gymnotus ardilai, is described from the R o de Oro near Bucaramanga in the Rio Magdalena Basin. Gymnotus ardilai is distinguishable from all congeners by the following combination of characters: 1, a clear patch at the caudal end of the anal fin; 2, two laterosensory canal pores (from the preopercular-mandibular series) in the dorso-posterior portion of the preopercle; 3, progressive loss of alternating dark and light pigment bands with the size; 4, a long head (10.2 11.2 % total length); 5, many (9 10) scales over anal fin pterygiophores; 6, few (47 48) pored lateral-line scales to first ramus; 7, low (84 n = 1) total number of pored lateral-line scales ; and, 8, relatively large eye (orbital diameter 8.5 9.0 % HL). Gymnotus ardilai is the first record of the genus from the Magdalena Basin and represents a unique record of Gymnotiformes from over 800 meters above sea level.References
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