Abstract
Chrysobrycon yoliae, new species, is described from a drainage flowing into the río Yucamia basin, río Ucayali basin, Peru. Chrysobrycon yoliaeis 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. eliasiand C. myersiby the presence of teeth on third pharyngobranchial (vs. the absence of teeth on this bone) and also differs from C. eliasiby 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 Chrysobryconspecies is provided.
Highlights
Chrysobrycon Weitzman & Menezes is diagnosed by a characteristic pouch scale on the ventral lobe of the caudal fin in mature males (Weitzman & Menezes, 1998)
Chrysobrycon species are strictly cis-Andean occurring in freshwater ecosystems between 153 and 585 m above sea level (a.s.l.) in the upper Amazon basin in Colombia, Ecuador, and Peru (Böhlke, 1958; Weitzman & Thomerson, 1970; VanegasRíos et al, 2011; Vanegas-Ríos et al, 2013b)
Chrysobrycon is a basal member of the tribe Xenurobryconini, phylogenetically diagnosed by the presence of a single large pouch scale with or without hypertrophied radii (Weitzman & Menezes, 1998)
Summary
Chrysobrycon Weitzman & Menezes is diagnosed by a characteristic pouch scale on the ventral lobe of the caudal fin in mature males (Weitzman & Menezes, 1998) This pouch scale is relatively small, somewhat elongated, curved, and horizontally folded so that its lateral face forms a laterally concave, broadly open pocket (Weitzman & Menezes, 1998). Chrysobrycon species are strictly cis-Andean occurring in freshwater ecosystems between 153 and 585 m above sea level (a.s.l.) in the upper Amazon basin in Colombia, Ecuador, and Peru (Böhlke, 1958; Weitzman & Thomerson, 1970; VanegasRíos et al, 2011; Vanegas-Ríos et al, 2013b). We describe these specimens as a new species of Chrysobrycon and provide a key to identify the species of the genus
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