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

Abstract

Chrysobrycon yoliae, new species, is described from a drainage flowing into the río Yucamia basin, río Ucayali basin, Peru. Chrysobrycon yoliae is readily distinguished from its congeners by the anterior tip of pelvic bone situated anterior to the fifth rib (vs. situated posterior to the fifth rib), the presence of 20-26 dentary teeth (vs. 11-19), and the possession of a terminal lateral-line tube between caudal-fin rays 10 and 11 (vs. the absence of this tube, except in C. eliasi). The new species differs from C. eliasi and C. myersi by the presence of teeth on third pharyngobranchial (vs. the absence of teeth on this bone) and also differs from C. eliasi by the dorsal-fin origin situated at vertical through anal-fin rays 5 to 7 (vs. located at vertical through anal-fin rays 8 to 10), the posterior extent of the ventral process of quadrate reaching the vertical through posterior margin of symplectic (vs. not reaching the vertical through posterior margin of symplectic), the dorsal-fin to adipose-fin length 26.8-28.8% SL (vs. 23.9-26.8% SL), and the body depth at dorsal-fin origin 34.4-42.2% SL (vs. 24.1-34.5% SL). A key for the identification of Chrysobrycon species is provided.Se describe Chrysobrycon yoliae, una nueva especie de un drenaje que fluye hacia la cuenca del río Yucamia, cuenca del río Ucayali, Perú. Chrysobrycon yoliae es fácilmente distinguible de sus congéneres por la punta anterior del hueso pélvico situada anterior a la quinta costilla (vs. situada posterior a la quinta costilla), la presencia de 20-26 dientes dentarios (vs. 11-19) y la presencia de tubo terminal de la línea lateral entre los radios caudales 10 y 11 (vs. la ausencia de este tubo, excepto en C. eliasi). La nueva especie difiere de C. eliasi y C. myersi por el desarrollo de dientes sobre el tercer faringobranquial (vs. la ausencia de dientes sobre este hueso) y también difiere de C. eliasi por el origen de la aleta dorsal ubicado en la vertical a través de los radios anales 5 a 7 (vs. ubicado en la vertical a través de los radios anales 8 a 10), por la extensión posterior del proceso ventral del cuadrado que alcanza la vertical que pasa por el margen posterior del simpléctico (vs. no alcanza la vertical que pasa por el borde posterior del simpléctico), por la distancia aleta dorsal-aleta adiposa 26,8% LE (vs. 23,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26],8% LE) y la altura del cuerpo en el origen de aleta dorsal 34,4-42,2% LE (vs. 24,1-34,5% LE). Se provee una clave para la identificación de las especies de Chrysobrycon.

A new species of Chrysobrycon (Characiformes, Characidae, Stevardiinae) from the Amazon River basin in Colombia, with a new diagnostic characteristic for the genus

“…mojicai ) and is more widespread in the Amazon Basin than in the Orinoco Basin. The Amazonian species of Chrysobrycon are mainly known from the geographical records of their descriptions (Böhlke, ; Weitzman & Thomerson, ; Vanegas‐Ríos et al ., , ) as well as from additional records provided by Vanegas‐Ríos et al . (2013 b ) for C .…”

“…The genus includes five valid species (including C. mojicai) and is more widespread in the Amazon Basin than in the Orinoco Basin. The Amazonian species of Chrysobrycon are mainly known from the geographical records of their descriptions (Böhlke, 1958;Weitzman & Thomerson, 1970;Vanegas-Ríos et al, 2011, 2014 as well as from additional records provided by Vanegas-Ríos et al (2013b) for C. hesperus and C. myersi. Although C. hesperus seems to be the most widespread species of the genus, occurring widely in the Amazon River basin of Colombia, Ecuador and Peru, the precise extent of its geographical distribution is yet to be determined.…”

“…Chrysobrycon was erected by Weitzman & Menezes () to include two species that had already been placed in Hysteronotus Eigenmann 1911, Chrysobrycon hesperus (Böhlke 1958) and Chrysobrycon myersi (Weitzman & Thomerson 1970) (Böhlke, ; Weitzman & Thomerson, ). Subsequent studies have revealed that Chrysobrycon is more species rich than previously thought and consequently, three more species were described (Vanegas‐Ríos et al ., , , ): Chrysobrycon eliasi Vanegas‐Ríos, Azpelicueta & Ortega 2011; Chrysobrycon guahibo Vanegas‐Ríos, Urbano‐Bonilla & Azpelicueta 2015; Chrysobrycon yoliae Vanegas‐Ríos, Azpelicueta & Ortega 2014.…”

“…myersi and C . yoliae (Weitzman & Menezes, ; Vanegas‐Ríos et al ., , ). During the examination of several characid species from the southern Amazon River basin in Colombia, some populations with a distinctive maxillary dentition were identified as Chrysobrycon .…”

“…The freshwater fish genus Chrysobrycon Weitzman & Menezes 1998 is part of the Stevardiinae, recognised by a group of hypertrophied scales that form a laterally open pocket on the lower caudal‐fin lobe in adult males (Weitzman & Menezes, ; Vanegas‐Ríos et al ., , ). According to Weitzman & Menezes (), the pocket is mainly constituted by a pouch scale, which is relatively small (compared with other related stevardiines), somewhat elongate, curved, confined to the dorsal region of the pouch opening and horizontally folded so that its lateral face is laterally concave.…”