Chrysobrycon eliasi, new species of stevardiine fish (Characiformes: Characidae) from the río Madre de Dios and upper río Manuripe basins, Peru

Abstract

Chrysobrycon eliasi is described from several drainages of río Madre de Dios and upper río Manuripe basins, río Madeira basin, Peru. The new species is distinguished from its congeners by the maxillary teeth, which are tricuspidate, bicuspidate and conical, and the terminal lateral-line tube developed between caudal-fin rays 10-11. Other characters that help to recognize C. eliasi are the possession of maxilla with 6-15 (usually 11) teeth occupying more than 70% of the length of the maxilla in adults, predorsal scales 18-22, dorsal-fin to hypural complex length 36.32-41.17% of standard length (SL), gill-gland length in males 3.57-5.05% SL, maxillary length 33.76-38.75% of head length, and branched anal-fin rays 24-30. The discovery of C. eliasi allows us to extend the geographic distribution of the genus to the southeast, into the río Madeira basin.Chrysobrycon eliasi se describe para varios drenajes en las cuencas de los ríos Madre de Díos y Alto Manuripe, cuenca del río Madeira, Peru. La nueva especie puede diferenciarse de sus congéneres por la presencia de dientes maxilares, que son tricuspidados, bicuspidados y cónicos, y el tubo terminal de la línea lateral desarrollado entre los radios caudales 10-11. Otros caracteres que ayudan a reconocer C. eliasi son la presencia de 6-15 (usualmente11) dientes maxilares ocupando más del 70% de la longitud de la maxila en adultos, escamas predorsales 18-22, longitud origen aleta dorsal-hipurales 36,32-41,17% de longitud estandard (LE), longitud de la glándula branquial en machos 3,57-5,05% LE, longitud de la maxila 33,76-38,75% de longitud de la cabeza, y radios ramificados en la aleta anal 24-30. El hallazgo de C. eliasi nos permite ampliar la distribución geográfica del género hacia el sureste en la cuenca del río Madeira.

Annotated list of freshwater fishes of the Limoncocha Lagoon, Napo river basin, northern Amazon region of Ecuador

“…Species identifications were performed consulting the taxonomic literature and identification keys (Géry 1977, Kullander 1986, Whitehead et al 1988, Vari 1984, 1991, 1992a, 1992b, Vari and Harold 2001, Malabarba 2004, Armbruster and Page 2006, Vanegas-Ríos et al 2011, Loeb 2012. A non-parametric jack-knife estimator was used to determine the number of possible species at the study site.…”

“…present 3-16 teeth in the maxilla, except for Chrysobrycon guahibo. In contrast, Gephyrocharax has fewer than 6 teeth in the maxilla (Géry 1977, Vanegas-Ríos et al 2011, Vanegas-Ríos and UrbanoBonilla 2017.…”

Chrysobrycon yoliae, a new species of stevardiin (Characiformes: Characidae) from the Ucayali basin, Peru

“…Chrysobrycon has three valid species: C. eliasi VanegasRíos, Azpelicueta & Ortega, C. hesperus (Böhlke), and C. myersi Weitzman & Menezes (Böhlke, 1958;Weitzman & Thomerson, 1970;Vanegas-Ríos et al, 2011). Chrysobrycon hesperus is the type species of the genus and was originally described for the río Napo basin in Ecuador (Böhlke, 1958).…”

“…Chrysobrycon myersi, a species distributed more southward than C. hesperus, is known from the río Pachitea basin in Peru (Weitzman & Thomerson, 1970). Chrysobrycon eliasi occurs along several localities flowing into the río Madre de Dios and upper río Manuripe basins in Peru (Vanegas-Ríos et al, 2011).…”

“…in the upper Amazon basin in Colombia, Ecuador, and Peru (Böhlke, 1958;Weitzman & Thomerson, 1970;VanegasRíos et al, 2011;Vanegas-Ríos et al, 2013b). According to Weitzman & Thomerson (1970), Vanegas-Ríos et al (2011), and Vanegas-Ríos et al (2013b), C. myersi is the only species that occurs in the río Ucayali basin. Chrysobrycon myersi is easily distinguished within the genus not only by its secondary sexually dimorphic characters in males (e.g., spinelets on pelvic-, anal-, and caudal-fin rays), but also by meristic and morphometric differences (Weitzman & Thomerson, 1970;Vanegas-Ríos et al, 2011).…”