Tres nuevas especies de <i>Hemibrycon</i> (Characiformes: Characidae) de la cuenca del río Magdalena, Colombia

Abstract

Tres nuevas especies de Hemibrycon (Characiformes: Characidae) de la cuenca del río Magdalena, Colombia. Fish biodiversity of aquatic ecosystems is highly threatened by different economic activities driven by human populations, and its description is increasingly a priority. For the Cauca-Magdalena River system we have described 14 species, and the purpose of this paper was to describe three new species belonging to the same genus Hemibrycon from the Nare and Guatapé River drainages of the middle Magdalena River, Colombia. The description was based on a series of 200 specimens, and the use of morphometric, meristic and osteological characters, as well as fish distribution and morphogeometric analytical methods. We have found that Hemibrycon fasciatus n. sp. (n=54) differs from other species of Hemibrycon (that also have a vertical humeral spot) in having: melanophores outlining the posterior margins of the scales along sides of body; humeral spot extending onto posterior margin of opercle; a dark lateral stripe, formed by deep pigment that is continuous with the peduncular spot; the toothed portion of the maxilla not reaching the dorsal margin of the dentary (vs. toothed portion of maxilla extending beyond dorsal margin of dentary); all maxillary teeth tricuspid (vs. some unicuspid teeth present on maxilla). H. cardalensis n. sp. (n=64) differs in having: a vertically elongate humeral spot that extends one or two scales below the lateral line canal. H. cardalensis n. sp. differs from all congeners in having the pigment of the caudal spot restricted to the ventral half of the caudal peduncle, and in having melanophores around the anterior scales of the lateral line. Hemibrycon antioquiae n. sp. (n=82) differs in having a circular humeral spot. It differs from the other species with a circular humeral spot, like H. mikrostiktos, in having a projection of disperse melanophores extending from the dorsal margin of the humeral spot to below the lateral stripe. Habitat data and environmental impacts caused by the construction of reservoirs for hydroelectric projects and other threats in the area are included, as well as a key to all species Hemibrycon present in the Magdalena River Basin. The synonymy of H. pautensis with H. polyodon is discussed and H. pautensis is revalidated. Rev. Biol. Trop. 61 (3): 1365-1387. Epub 2013 September 01.

A new species of Hemibrycon (Characiformes, Characidae) from the upper San Juan River drainage, Pacific versant, Colombia

“…This characteristic has also been observed in several other species of Hemibrycon (Bertaco et al 2007; Román-Valencia et al 2010) and has been suggested as a synapomorphy for the genus by Arcila-Mesa (2008) and Román-Valencia et al (2013).…”

“…Although species of Hemibrycon have a similar color pattern throughout their geographic distribution, subtle differences in the concentration and distribution of black pigment in the humeral and caudal regions have been used to diagnose new species (Bertaco and Malabarba 2010; Román-Valencia et al 2009a, b, c, 2013; Román-Valencia and Arcila-Mesa 2010). …”

“…But there are exceptions such as Hemibrycon dariensis , which occurs in Pacific drainages, Hemibrycon santamartae and Hemibrycon sp. n. found in northern Colombia, and Hemibrycon metae from the upper Meta River drainage in the Orinoco River Basin (Bertaco and Malabarba 2010; Román-Valencia and Ruiz-C 2007; Román-Valencia et al 2009a; Román-Valencia et al 2013). The discovery of a new species of Hemibrycon from the upper San Juan River Basin, Pacific versant in Colombia, is a result of the authors’ ongoing revision of Hemibrycon (Román-Valencia et al 2010; 2013) and is further proof of undocumented biodiversity in the genus.…”

A new species of Hemibrycon (Characiformes, Characidae, Stevardiinae) from the upper Magdalena River basin in Colombia

“…The first pre‐ural centrum plus first ural centrum (PU1 + U1) were counted as one element along with four vertebrae of the Weberian apparatus. Original descriptions of several Hemibrycon species from the Magdalena–Cauca Basin were utilized to compare morphological characters (Román‐Valencia, ; Bertaco et al, ; Bertaco, ; Román‐Valencia et al, , ; Román‐Valencia & Arcila‐Mesa, ). Finally, some dissected specimens were photographed with a clearing photographic system developed for this study.…”

“…In the past 10 years, 20 species of Hemibrycon have been described (Fricke & Eschmeyer, ). Sixteen species have been described from Colombia, 14 of which are from the Magdalena–Cauca Basin (Román‐Valencia & Ruiz, ; Román‐Valencia & Arcila‐Mesa, , , ; Román‐Valencia et al, , ; García‐Alzate et al, ). However, problems with species delimitation within the genus have been highlighted by Thomaz et al .…”