Description of a new species of Moenkhausia (Characiformes: Characidae) from the upper Paraguay basin, Central Brazil, with comments on its phylogenetic relationships

Abstract

A new species of Moenkhausia is described from tributaries of the upper rio Sepotuba, Paraguay basin, Brazil. The new species is distinguished from its congeners by a combination of characters, including an inconspicuous oval-shaped vertically elongated humeral blotch, extending horizontally from third through five lateral-line scales, and vertically from third row above lateral line to first row below it, followed by a diffuse field of dark chromatophores in the flank, combined with a well-defined dark line at the base of the anal fin. Furthermore, the phylogenetic position of the new species is presented based on molecular data, showing a close relationship among species of Moenkhausia and Hemigrammus that have a well-defined dark line at the base of the anal fin. Until this moment, this species is only known from in the upper rio Sepotuba basin.

Geographic variation of Moenkhausia bonita (Characiformes: Characidae) in the rio de la Plata basin, with distributional comments on M. intermedia

“…Amazon, Orinoco, La Plata, and San Francisco). This genus reaches its greatest diversity in the rio Amazon basin (~ 73 species), followed by the coastal basins of Guyana, Suriname, and French Guiana (~ 14) (Lima et al, 2003;Britzke et al, 2018;Fricke et al, 2019). The morphological definition of Moenkhausia is based on a combination of non-exclusive characteristics (e.g.…”