Apteronotus jurubidae

distribution

Distribution: Jurubidá River basin, Colombia (de Santana, Maldonado-Ocampo, 2004).

Checklist of Gymnotiformes (Osteichthyes: Ostariophysi) and catalogue of primary types

description

Original description (Fowler, 1944: 242): “ Depth 64 / 5; head 62 / 5, width 24 / 5. Snout (in profile) 3 in head; eye 141 / 2, 4 in snout, 2 in interorbital, edges not free from skin of head; mouth extends back opposite front edge of eye, length from snout tip 3 in head; mouth rather narrow, width in front equals eye, closed mandible well included; nostril well separated, anterior in short tube and posterior midway in space to eye; interorbital 53 / 4 in head, convexly elevated; opercle with few striae. Gill opening 51 / 2 in head. Scales 88 in lateral line, continuous, with slender well exposed tubes. Scales on back and upper part of body large, all smaller on lower half of sides and on caudal peduncle extend over greater part of caudal, basally. Head and prepectoral region naked, and scales obsolete, small and embedded on upper hind part of head above opercle. Dorsal reduced to short simple posterior filament, its length 2 in head; very long anal with 167 branched rays, greatest fin height 21 / 4 in head, origin of fin well before gill opening; caudal peduncle slender, depth 83 / 5 in head; caudal 33 / 5, small, rounded behind; pectoral 11 / 2, rays 15. Color in alcohol largely

Redescription of Apteronotus mariae (Eigenmann & Fisher, 1914) and the taxonomic status of Apteronotus jurubidae (Fowler, 1944) (Gymnotiformes: Apteronotidae).

diagnosis

Using the information herein and by de Santana (2002; 2003), it is possible to distinguish A. jurubidae from A. mariae by the following traits: body coloration uniformly brown vs. light brown with small black spots distributed over the integument; dorsal region with uniform coloration vs. clear band from the preorbital region to the beginning of dorsal mid-sagittal electroreceptor organ in A. mariae.

Redescription of Apteronotus mariae (Eigenmann & Fisher, 1914) and the taxonomic status of Apteronotus jurubidae (Fowler, 1944) (Gymnotiformes: Apteronotidae).

discussion

Comments on endemism in the Rio Magdalena basin. A detailed phylogenetic analysis of Apteronotus is beyond the scope of the present paper and we herein confined ourselves to discuss the relationships of the two species with the apteronotids from the Trans-Andean region based on a preliminary hypothesis offered by de Santana (2002). That analysis was based on 97 morphological characters from 32 apteronotids taxa, with two species of Sternopygidae used as outgroups. Apteronotus mariae has an apomorphic character among the Trans-Andean apteronotids, the finely spotted coloration on the body. The presence of one or two clear bands in adults of A. mariae is a polymorphic feature. However, the presence of those bands could have at least two different patterns in the Trans-Andean apteronotids: (1) two clear bands present in juveniles and one clear band present in adults (e. g., Apteronotus cuchillo); and (2) one clear band present throughout development (e. g., Apteronotus rostratus). Some relevant characters used to identify and to infer the relationships in ghost knifefishes (above 100 mm TL) from the Trans-Andean region are summarized in Table 2. However, these character states can rep

Redescription of Apteronotus mariae (Eigenmann & Fisher, 1914) and the taxonomic status of Apteronotus jurubidae (Fowler, 1944) (Gymnotiformes: Apteronotidae).